JP2015167892A - Catalyst structure having laminar double hydroxide and manufacturing method therefor - Google Patents
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- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 title claims abstract description 115
- 239000003054 catalyst Substances 0.000 title claims abstract description 96
- 238000004519 manufacturing process Methods 0.000 title claims description 23
- 150000001450 anions Chemical class 0.000 claims abstract description 31
- 150000001768 cations Chemical class 0.000 claims abstract description 26
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 22
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 16
- 229910052802 copper Inorganic materials 0.000 claims abstract description 14
- 229910052709 silver Inorganic materials 0.000 claims abstract description 13
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 12
- 229910052718 tin Inorganic materials 0.000 claims abstract description 11
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 11
- 239000000843 powder Substances 0.000 claims description 63
- 238000000034 method Methods 0.000 claims description 42
- 239000002994 raw material Substances 0.000 claims description 41
- 239000012018 catalyst precursor Substances 0.000 claims description 36
- 238000010304 firing Methods 0.000 claims description 34
- 238000001354 calcination Methods 0.000 claims description 28
- 239000007864 aqueous solution Substances 0.000 claims description 27
- 238000000465 moulding Methods 0.000 claims description 25
- 229910052751 metal Inorganic materials 0.000 claims description 23
- 239000002184 metal Substances 0.000 claims description 23
- 239000000243 solution Substances 0.000 claims description 23
- 238000005470 impregnation Methods 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 18
- 239000011230 binding agent Substances 0.000 claims description 16
- 238000010335 hydrothermal treatment Methods 0.000 claims description 15
- 239000011148 porous material Substances 0.000 claims description 13
- 150000001875 compounds Chemical class 0.000 claims description 11
- 230000008929 regeneration Effects 0.000 claims description 8
- 238000011069 regeneration method Methods 0.000 claims description 8
- 239000000835 fiber Substances 0.000 claims description 5
- 239000008188 pellet Substances 0.000 claims description 5
- 230000000717 retained effect Effects 0.000 claims description 4
- 238000004455 differential thermal analysis Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical group O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 26
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 18
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 17
- 239000011777 magnesium Substances 0.000 description 15
- 238000006722 reduction reaction Methods 0.000 description 13
- 229960001545 hydrotalcite Drugs 0.000 description 12
- 229910001701 hydrotalcite Inorganic materials 0.000 description 12
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 description 11
- 239000012298 atmosphere Substances 0.000 description 10
- 239000010949 copper Substances 0.000 description 10
- 239000001569 carbon dioxide Substances 0.000 description 9
- 229910002092 carbon dioxide Inorganic materials 0.000 description 9
- 238000005336 cracking Methods 0.000 description 9
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 239000012071 phase Substances 0.000 description 7
- 239000011135 tin Substances 0.000 description 7
- 239000011701 zinc Substances 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- 235000011114 ammonium hydroxide Nutrition 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 239000004809 Teflon Substances 0.000 description 5
- 229920006362 Teflon® Polymers 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000018044 dehydration Effects 0.000 description 5
- 238000006297 dehydration reaction Methods 0.000 description 5
- -1 hydrotalcite compound Chemical class 0.000 description 5
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 5
- 239000004926 polymethyl methacrylate Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 4
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 238000009694 cold isostatic pressing Methods 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000006356 dehydrogenation reaction Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229920000609 methyl cellulose Polymers 0.000 description 3
- 239000001923 methylcellulose Substances 0.000 description 3
- 235000010981 methylcellulose Nutrition 0.000 description 3
- 230000001172 regenerating effect Effects 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- QANIADJLTJYOFI-UHFFFAOYSA-K aluminum;magnesium;carbonate;hydroxide;hydrate Chemical compound O.[OH-].[Mg+2].[Al+3].[O-]C([O-])=O QANIADJLTJYOFI-UHFFFAOYSA-K 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 239000011229 interlayer Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 238000007569 slipcasting Methods 0.000 description 2
- 239000012279 sodium borohydride Substances 0.000 description 2
- 229910000033 sodium borohydride Inorganic materials 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 241000135309 Processus Species 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000007771 core particle Substances 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 235000013312 flour Nutrition 0.000 description 1
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- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
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- 238000007254 oxidation reaction Methods 0.000 description 1
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- 229920003023 plastic Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
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- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
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Abstract
Description
本発明は、層状複水酸化物を備えた触媒構造体及びその製造方法に関する。 The present invention relates to a catalyst structure including a layered double hydroxide and a method for producing the same.
ハイドロタルサイトに代表される層状複水酸化物（Layered Double Hydroxide）は、水酸化物の層と層の間に交換可能な陰イオンを有する物質群であり、その特徴を活かして、触媒や吸着剤、あるいは耐熱性向上のための高分子中の分散剤等として利用されている。 Layered Double Hydroxide, represented by hydrotalcite, is a group of substances that have anions that can be exchanged between hydroxide layers. It is used as an agent or a dispersant in a polymer for improving heat resistance.
例えば、引用文献１（特開２００５−０８９２７７号公報）には、Ｔｉ、Ｚｒ、Ｃｅ及びＷから選ばれる一種又は二種以上の元素を含有するハイドロタルサイト類化合物粒子粉末が開示されており、顔料、触媒、触媒前駆体等の用途が記載されている。引用文献２（特開２００１−０７９４１５号公報）には、ニッケル及び／又は銅を含有し、ハイドロタルサイト構造を有する化合物からなる酢酸メチル及び／又は酢酸合成用触媒が開示されている。引用文献３（特許第５２６５１２３号公報）には、ハイドロタルサイト表面に、Ｃｕ、Ａｇ、Ａｕから選択された少なくとも１種の金属を粒子として固定化してなるアルコール脱水素用触媒が開示されている。引用文献１〜３はいずれも層状複水酸化物の圧粉体（未焼結体）を触媒担体として用いるものである。 For example, Cited Document 1 (Japanese Patent Laid-Open No. 2005-089277) discloses a hydrotalcite compound particle powder containing one or more elements selected from Ti, Zr, Ce and W, Applications such as pigments, catalysts, catalyst precursors, etc. are described. Cited Document 2 (Japanese Patent Application Laid-Open No. 2001-079415) discloses a catalyst for synthesizing methyl acetate and / or acetic acid comprising a compound containing nickel and / or copper and having a hydrotalcite structure. Cited Document 3 (Patent No. 5265123) discloses an alcohol dehydrogenation catalyst in which at least one metal selected from Cu, Ag, and Au is immobilized as particles on the hydrotalcite surface. . In each of the cited documents 1 to 3, a layered double hydroxide green compact (unsintered body) is used as a catalyst carrier.
一方、前駆体としての層状複水酸化物を焼成して複酸化物とし、この複酸化物を触媒担体として用いる技術も提案されている。例えば、引用文献４（特開２００３−２２５５６６号公報）には、マグネシウムとアルミニウムとを含む多孔性複合酸化物成形体の周縁部分にニッケル金属微粒子が担持された炭化水素分解用触媒が開示されている。引用文献５（特開２００４−２５５２４５号公報）には、マグネシウム及びアルミニウムからなる層状複水酸化物芯粒子の表面にマグネシウム、ニッケル及びアルミニウムからなる層状複水酸化物層を形成した粉末を加熱焼成して酸化物粒子粉末を得、次いで、該酸化物粒子粉末を加熱還元して酸化物粒子粉末中のニッケルを金属ニッケル微粒子にして得られる炭化水素分解用触媒が開示されている。引用文献６（特開平１１−３５０９４５号公報）には、Ｍｇ／Ａｌ−ハイドロタルサイトを４００〜６００℃で１〜１０時間か焼して硫黄酸化物吸蔵成分として排ガス浄化装置において使用することが開示されている。このように、引用文献４〜６に開示される触媒担体は焼成を経て得られた複酸化物であって、層状複水酸化物ではない。 On the other hand, a technique has also been proposed in which a layered double hydroxide as a precursor is calcined to form a double oxide, and this double oxide is used as a catalyst carrier. For example, cited reference 4 (Japanese Patent Laid-Open No. 2003-225565) discloses a hydrocarbon cracking catalyst in which nickel metal fine particles are supported on the peripheral portion of a porous composite oxide molded body containing magnesium and aluminum. Yes. In Cited Document 5 (Japanese Patent Laid-Open No. 2004-255245), a powder in which a layered double hydroxide layer composed of magnesium, nickel and aluminum is formed on the surface of a layered double hydroxide core particle composed of magnesium and aluminum is heated and fired. Thus, a catalyst for cracking hydrocarbons obtained by obtaining oxide particle powder and then heating and reducing the oxide particle powder to make nickel in the oxide particle powder into metal nickel fine particles is disclosed. In Cited Document 6 (Japanese Patent Laid-Open No. 11-350945), Mg / Al-hydrotalcite is calcined at 400 to 600 ° C. for 1 to 10 hours and used as a sulfur oxide storage component in an exhaust gas purification apparatus. It is disclosed. Thus, the catalyst carriers disclosed in the cited documents 4 to 6 are double oxides obtained through calcination and not layered double hydroxides.
しかしながら、引用文献１〜３に開示される触媒担体は層状複水酸化物の圧粉体で形成されているため、焼結体と比べて機械的強度が低い。また、層状複水酸化物を触媒担体として有機化学反応に用いる場合、劣化や反応への関与が懸念される有機バインダーは使用することができず、層状複水酸化物を粉末形態で使用せざるを得ないことになるが、使用後の触媒を回収するためには触媒／触媒担体を遠心分離させて濾過するといった煩雑な工程が必要となる。一方、引用文献４〜６に開示される触媒担体は前駆体としての層状複水酸化物を焼成した結果、複酸化物の形態を有しているため、層状複水酸化物（特に水酸基）に起因する有利な特性を触媒担体において得ることはできない。 However, since the catalyst supports disclosed in the cited documents 1 to 3 are formed of a layered double hydroxide compact, the mechanical strength is lower than that of the sintered body. In addition, when a layered double hydroxide is used as a catalyst carrier in an organic chemical reaction, an organic binder that is concerned about deterioration or participation in the reaction cannot be used, and the layered double hydroxide must be used in a powder form. However, in order to recover the used catalyst, a complicated process of centrifuging and filtering the catalyst / catalyst support is required. On the other hand, the catalyst carriers disclosed in the cited documents 4 to 6 have the form of a double oxide as a result of calcining the layered double hydroxide as a precursor. The resulting advantageous properties cannot be obtained in the catalyst support.
本発明者らは、今般、圧粉体に比べて機械的強度が高く、かつ、使用後に回収し易い、層状複水酸化物ベースの触媒構造体を提供できるとの知見を得た。 The present inventors have now found that a layered double hydroxide-based catalyst structure can be provided that has higher mechanical strength than a green compact and is easy to recover after use.
したがって、本発明の目的は、圧粉体に比べて機械的強度が高く、かつ、使用後に回収し易い、層状複水酸化物ベースの触媒構造体を提供することにある。 Accordingly, an object of the present invention is to provide a layered double hydroxide-based catalyst structure that has higher mechanical strength than a green compact and is easy to recover after use.
本発明の一態様によれば、一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で示される層状複水酸化物を主相とする層状複水酸化物焼結体と、
前記層状複水酸化物焼結体上に担持され、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種を含んでなる触媒と、
を備えた、触媒構造体が提供される。
According to one embodiment of the present invention, the general formula: M 2+ 1−x M 3+ x (OH) 2 A n− x / n · mH 2 O (wherein M 2+ is a divalent cation and M 3+ is a trivalent cation, a n-n-valent anion, n represents an integer of 1 or more, x is a main phase of the layered double hydroxide represented by a is) 0.1 to 0.4 A layered double hydroxide sintered body;
At least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag supported on the layered double hydroxide sintered body. A catalyst comprising
A catalyst structure is provided.
本発明の別の一態様によれば、触媒構造体の製造方法であって、
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる原料粉末を用意する工程と、
前記原料粉末を成形して、成形体を得る工程と、
前記成形体を水熱処理及び／又は仮焼し、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された触媒前駆体溶液に含浸させた後、焼成する、あるいは前記成形体を焼成した後、前記触媒前駆体溶液に含浸させ、それにより触媒前駆体を担持した酸化物焼成体を得る工程と、
前記触媒前駆体を担持した酸化物焼成体に還元処理を施して前記金属を触媒として生成させる工程と、
前記触媒が生成された酸化物焼成体を、ｎ価の陰イオンを含む水溶液中又はその直上に保持して層状複水酸化物へ再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る工程と、
を含む、方法が提供される。
According to another aspect of the present invention, a method for producing a catalyst structure comprising:
General formula: M 2+ 1-x M 3+ x (OH) in 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, A a step of preparing a raw material powder composed of a layered double hydroxide represented by: n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4.
Molding the raw material powder to obtain a molded body;
The molded body is hydrothermally treated and / or calcined, and at least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. After impregnating the catalyst precursor solution in which the compound containing the metal is dissolved, firing, or firing the molded body, and then impregnating the catalyst precursor solution, thereby firing the oxide supporting the catalyst precursor. Obtaining a body;
A step of reducing the oxide calcined body carrying the catalyst precursor to produce the metal as a catalyst;
The oxide fired body in which the catalyst is generated is retained in or immediately above an aqueous solution containing an n-valent anion to be regenerated into a layered double hydroxide, whereby a layered double hydroxide sintered body and a catalyst are obtained. Obtaining a catalyst structure comprising:
A method is provided comprising:
本発明の更に別の一態様によれば、触媒構造体の製造方法であって、
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる粉末と、バインダー及び／又は造孔材とを混合して、原料粉末を用意する工程と、
前記原料粉末を成形して、成形体を得る工程と、
前記成形体を仮焼し、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された触媒前駆体溶液に含浸させた後、焼成する、あるいは前記成形体を焼成した後、前記触媒前駆体溶液に含浸させ、それにより触媒前駆体を担持した酸化物焼成体を得る工程と、
前記触媒前駆体を担持した酸化物焼成体に還元処理を施して前記金属を触媒として生成させる工程と、
前記触媒が生成された酸化物焼成体を、ｎ価の陰イオンを含む水溶液中又はその直上に保持して層状複水酸化物へ再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る工程と、
を含む、方法が提供される。
According to yet another aspect of the present invention, a method for producing a catalyst structure comprising:
General formula: M 2+ 1-x M 3+ x (OH) in 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, A n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4) and a binder and / or pore former, And preparing a raw material powder,
Molding the raw material powder to obtain a molded body;
The molded body is calcined, and a compound containing at least one metal selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. Impregnating the dissolved catalyst precursor solution and then calcining, or calcining the molded body and then impregnating the catalyst precursor solution, thereby obtaining an oxide calcined body carrying the catalyst precursor; ,
A step of reducing the oxide calcined body carrying the catalyst precursor to produce the metal as a catalyst;
The oxide fired body in which the catalyst is generated is retained in or immediately above an aqueous solution containing an n-valent anion to be regenerated into a layered double hydroxide, whereby a layered double hydroxide sintered body and a catalyst are obtained. Obtaining a catalyst structure comprising:
A method is provided comprising:
触媒構造体
本発明の触媒構造体は、層状複水酸化物焼結体と、この層状複水酸化物焼結体上に担持される触媒とを備えてなる。触媒は、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種を含んでなる。一方、層状複水酸化物焼結体は、一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で示される層状複水酸化物を主相とするものである。ここで、「層状複水酸化物焼結体」は、層状複水酸化物の複数の粒子が焼成により互いに結合（ネッキング）してなるものを意味する。もっとも、層状複水酸化物は焼成により水酸基を失い複酸化物に変化してしまうが、この複酸化物に水熱処理等による再生処理を施して複水酸化物に再生することができ、こうして再生されたものを「層状複水酸化物焼結体」と本明細書では称するものとする。すなわち、層状複水酸化物焼結体は、典型的には、焼成後水熱処理を経て作製されたものである。したがって、層状複水酸化物焼結体は、引用文献１〜３に開示されるような圧粉体よりも高い機械的強度を有することができる。そうでありながら、引用文献４〜６に開示される触媒担体のように複酸化物の形態ではなく、層状複水酸化物（特に水酸基）に起因する特性を触媒担体において発揮させることができる。例えば、触媒担体の表面に水酸基が存在することで、その上に担持される触媒の活性を高められる、等の利点がもたらされる。その上、層状複水酸化物焼結体は、粉末形態ではなく焼結体であるが故に、所定の形状を付与することができ、それ故、使用後の触媒の回収もし易い。すなわち、本発明によれば、圧粉体に比べて機械的強度が高く、かつ、使用後に回収し易い、層状複水酸化物ベースの触媒構造体を提供することができる。
Catalyst structure The catalyst structure of the present invention comprises a layered double hydroxide sintered body and a catalyst supported on the layered double hydroxide sintered body. The catalyst comprises at least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. On the other hand, the layered double hydroxide sintered body, the general formula: M 2+ 1-x M 3+ x (OH) 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, a n-n-valent anion, n represents an integer of 1 or more, x is primarily a layered double hydroxide represented by a is) 0.1 to 0.4 It is something to be phased. Here, the “layered double hydroxide sintered body” means a structure in which a plurality of particles of a layered double hydroxide are bonded (necked) to each other by firing. However, the layered double hydroxide loses the hydroxyl group by firing and changes to a double oxide. However, this double oxide can be regenerated to double hydroxide by subjecting it to regeneration treatment such as hydrothermal treatment. This is referred to as a “layered double hydroxide sintered body” in this specification. That is, the layered double hydroxide sintered body is typically produced through a hydrothermal treatment after firing. Therefore, the layered double hydroxide sintered body can have higher mechanical strength than the green compact as disclosed in References 1 to 3. In spite of this, the characteristics resulting from the layered double hydroxide (particularly hydroxyl group) can be exhibited in the catalyst support, not the form of the double oxide as in the catalyst supports disclosed in the cited documents 4 to 6. For example, the presence of a hydroxyl group on the surface of the catalyst carrier brings advantages such as enhancing the activity of the catalyst supported thereon. In addition, since the layered double hydroxide sintered body is not a powder form but a sintered body, the layered double hydroxide sintered body can be given a predetermined shape, and therefore, the used catalyst can be easily recovered. That is, according to the present invention, it is possible to provide a layered double hydroxide-based catalyst structure that has higher mechanical strength than a green compact and is easy to recover after use.
本発明の層状複水酸化物焼結体は、触媒構造体の使用態様に応じて所望の形状を有することができる。いかなる形状であろうと、層状複水酸化物焼結体は、粉末形態ではなく焼結体であるが故に、粉末形態の触媒よりも使用後の触媒の回収が格段にし易い。好ましい形状の例としては、球状、円柱状、中空円柱状、ペレット状、ハニカム状、繊維状、メッシュ状、球に突起を設けた形状、球に窪みを設けた形状、及びそれらの組み合わせが挙げられる。特に、ハニカム状であると、流路が形成されているため低圧損であり、一体形成されているため交換が容易という利点がある。また、中空円柱状、あるいは球に突起を設けた形状であると、表面積を上げて反応サイトを増やす利点がある。球に窪みを設けた形状であると、球表面の流れの剥離が抑制され、流れの抵抗を抑制する利点がある。 The layered double hydroxide sintered body of the present invention can have a desired shape depending on the use mode of the catalyst structure. Whatever the shape, the layered double hydroxide sintered body is not a powder form but a sintered body, and therefore, recovery of the catalyst after use is much easier than a powder form catalyst. Examples of preferable shapes include spherical shapes, cylindrical shapes, hollow cylindrical shapes, pellet shapes, honeycomb shapes, fiber shapes, mesh shapes, shapes in which spheres are provided with protrusions, shapes in which spheres are provided with depressions, and combinations thereof. It is done. In particular, the honeycomb shape has an advantage that the flow path is formed, resulting in low-pressure loss, and the replacement is easy because it is integrally formed. Moreover, when it is a hollow cylinder shape or the shape which provided the processus | protrusion on the bulb | ball, there exists an advantage which increases a surface area and increases a reaction site. When the sphere has a shape with a depression, separation of the flow on the sphere surface is suppressed, and there is an advantage of suppressing flow resistance.
本発明の層状複水酸化物焼結体は、一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で示される層状複水酸化物を主相とするものであり、好ましくは上記層状複水酸化物のみから実質的になる（又はのみからなる）。上記一般式において、Ｍ２＋は任意の２価の陽イオンでありうるが、好ましい例としてはＭｇ２＋、Ｃａ２＋及びＺｎ２＋が挙げられ、より好ましくはＭｇ２＋である。Ｍ３＋は任意の３価の陽イオンでありうるが、好ましい例としてはＡｌ３＋又はＣｒ３＋が挙げられ、より好ましくはＡｌ３＋である。Ａｎ−は任意の陰イオンでありうるが、好ましい例としてはＯＨ−及びＣＯ３ ２−が挙げられる。したがって、上記一般式は、少なくともＭ２＋がＭｇ２＋を、Ｍ３＋がＡｌ３＋を含み、Ａｎ−がＯＨ−及び／又はＣＯ３ ２−を含むのが好ましい。ｎは１以上の整数であるが、好ましくは１又は２である。ｘは０．１〜０．４であるが、好ましくは０．２〜０．３５である。 Layered double hydroxides sintered body of the present invention have the general formula: M 2+ 1-x M 3+ x (OH) 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation , M 3+ is a trivalent cation, a n-n-valent anion, n represents an integer of 1 or more, x is a layered double hydroxide represented by a is) 0.1 to 0.4 It is a main phase, and preferably consists essentially of (or consists only of) the above layered double hydroxide. In the above general formula, M 2+ may be any divalent cation, and preferred examples include Mg 2+ , Ca 2+ and Zn 2+ , and more preferably Mg 2+ . M 3+ may be any trivalent cation, but preferred examples include Al 3+ or Cr 3+ , and more preferred is Al 3+ . A n- may be any anion, preferred examples OH - and CO 3 2- and the like. Accordingly, the general formula is at least M 2+ is Mg 2+, include M 3+ is Al 3+, A n-is OH - and / or CO preferably contains 3 2-. n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35.
本発明の層状複水酸化物焼結体は４０％以上の相対密度を有するのが好ましい。この範囲であると触媒構造体の形状を保持するのに適した強度を確保しやすくなる。特に、緻密性を確保する観点からすれば、相対密度は好ましくは９０％以上、より好ましくは９４％以上である。このように高い相対密度であると層状複水酸化物焼結体の緻密性が向上するため、更なる高強度を得ることができる。一方、多孔性を確保する観点からすれば、相対密度は４０％以上かつ９０％未満であるのが好ましく、より好ましくは４５〜８５％である。このような範囲内の相対密度であると層状複水酸化物焼結体の多孔性が向上するため、表面積が大きく処理能力の高い触媒構造体を得ることができる。なお、相対密度は、試料の寸法及び重量から密度を算出し、この密度を理論密度で除することにより決定することができる。 The layered double hydroxide sintered body of the present invention preferably has a relative density of 40% or more. Within this range, it becomes easy to ensure a strength suitable for maintaining the shape of the catalyst structure. In particular, from the viewpoint of ensuring denseness, the relative density is preferably 90% or more, more preferably 94% or more. Since the denseness of the layered double hydroxide sintered body is improved at such a high relative density, a further high strength can be obtained. On the other hand, from the viewpoint of ensuring porosity, the relative density is preferably 40% or more and less than 90%, more preferably 45 to 85%. Since the porosity of the layered double hydroxide sintered body is improved when the relative density is within such a range, a catalyst structure having a large surface area and a high treatment capacity can be obtained. The relative density can be determined by calculating the density from the size and weight of the sample and dividing this density by the theoretical density.
本発明の層状複水酸化物焼結体は、層状複水酸化物主相が、示差熱分析において３００℃以下に明確な吸熱ピークが観察されない層状複水酸化物粒子から構成されるのが好ましい。すなわち、示差熱分析において主に２００℃近辺に観測される明確な吸熱ピークは層間水の脱離によるものと言われており、それに伴って急激に層間距離が変化するなどの大きな構造変化があるとされ、安定な温度領域が狭い可能性が推測されるからである。 In the layered double hydroxide sintered body of the present invention, the layered double hydroxide main phase is preferably composed of layered double hydroxide particles in which no clear endothermic peak is observed at 300 ° C. or lower in differential thermal analysis. . That is, a clear endothermic peak observed mainly in the vicinity of 200 ° C. in differential thermal analysis is said to be due to desorption of interlayer water, and there is a large structural change such as a sudden change in interlayer distance. This is because the possibility that the stable temperature region is narrow is estimated.
触媒は、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種を含んでなる。これらの金属触媒はいずれも層状複水酸化物にとって許容可能な温度範囲（典型的には約１００℃〜約２００℃）で公知の触媒活性を呈することができるものである。したがって、触媒構造体の使用される用途に応じて最適な触媒を上記群から適宜選択すればよい。例えばアルコール脱水素反応の用途においては、Ｃｕ、Ａｇ及び／又はＡｕが好ましい。アルコール酸化反応の用途においてはＡｕが好ましい。芳香族ニトロ化合物の還元反応の用途においてはＡｇが好ましい。 The catalyst comprises at least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. Any of these metal catalysts can exhibit a known catalytic activity in a temperature range acceptable for the layered double hydroxide (typically about 100 ° C. to about 200 ° C.). Therefore, an optimal catalyst may be appropriately selected from the above group according to the use for which the catalyst structure is used. For example, in the application of alcohol dehydrogenation, Cu, Ag and / or Au are preferable. Au is preferred for use in alcohol oxidation reactions. Ag is preferred for use in the reduction reaction of aromatic nitro compounds.
製造方法
本発明の層状複水酸化物構造体は、あらゆる方法によって作製されたものであってもよい。以下に好ましい製造方法として、緻密化に適した第一の態様による製造方法と、多孔化に適した第二の態様による製造方法を説明する。
Production Method The layered double hydroxide structure of the present invention may be produced by any method. Hereinafter, as a preferable manufacturing method, a manufacturing method according to the first aspect suitable for densification and a manufacturing method according to the second aspect suitable for porosity will be described.
（Ｉ）第一の態様による製造方法
本発明の第一の態様によれば、触媒構造体の製造は、（１）層状複水酸化物からなる原料粉末を用意し、（２）原料粉末を成形し、（３）触媒前駆体溶液への含浸及び焼成を施し、（４）得られた酸化物焼成体に還元処理を施し、（５）酸化物焼成体を層状複水酸化物へ再生することにより行うことができる。この第一の態様による製造方法は、例えば相対密度が９０％以上といった、緻密性の高い層状複水酸化物焼結体を得るのに適している。
(I) Production method according to the first aspect According to the first aspect of the present invention, the catalyst structure is produced by preparing (1) a raw material powder comprising a layered double hydroxide, and (2) a raw material powder. (3) impregnation and firing in the catalyst precursor solution, (4) subjecting the obtained oxide fired body to reduction treatment, and (5) regenerating the oxide fired body into a layered double hydroxide. Can be done. The manufacturing method according to the first aspect is suitable for obtaining a highly dense layered double hydroxide sintered body having a relative density of 90% or more, for example.
（１）原料粉末の用意
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる原料粉末を用意する。上記一般式において、Ｍ２＋は任意の２価の陽イオンでありうるが、好ましい例としてはＭｇ２＋、Ｃａ２＋及びＺｎ２＋が挙げられ、より好ましくはＭｇ２＋である。Ｍ３＋は任意の３価の陽イオンでありうるが、好ましい例としてはＡｌ３＋又はＣｒ３＋が挙げられ、より好ましくはＡｌ３＋である。Ａｎ−は任意の陰イオンでありうるが、好ましい例としてはＯＨ−及びＣＯ３ ２−が挙げられる。したがって、上記一般式は、少なくともＭ２＋がＭｇ２＋を、Ｍ３＋がＡｌ３＋を含み、Ａｎ−がＯＨ−及び／又はＣＯ３ ２−を含むのが好ましい。ｎは１以上の整数であるが、好ましくは１又は２である。ｘは０．１〜０．４であるが、好ましくは０．２〜０．３５である。このような原料粉末は市販の層状複水酸化物製品であってもよいし、硝酸塩や塩化物を用いた液相合成法等の公知の方法にて作製した原料であってもよい。原料粉末の粒径は、所望の層状複水酸化物焼結体が得られる限り限定されないが、体積基準Ｄ５０平均粒径が０．１〜１.０μｍであるのが好ましく、より好ましくは０．３〜０．８μｍである。原料粉末の粒径が細かすぎると粉末が凝集しやすく、大きすぎると成形性が悪くなるためである。なお、後述する成形前に、層状複水酸化物の粉末を仮焼して酸化物粉末としてもよい。この際の仮焼温度は、構成するＭ２＋及びＭ３＋によって多少の差があるが、５００℃以下が好ましく、より好ましくは３８０〜４６０℃とし、原料粒径が大きく変化しない領域で行う。なお、この第一の態様による製造方法においては、緻密性の高い層状複水酸化物焼結体を得る観点から、原料粉末はバインダー及び造孔材を含まないのが好ましい。
(1) Raw material powders prepared general formula: M 2+ 1-x M 3+ x (OH) 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent A raw material powder comprising a layered double hydroxide represented by: An n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4. To do. In the above general formula, M 2+ may be any divalent cation, and preferred examples include Mg 2+ , Ca 2+ and Zn 2+ , and more preferably Mg 2+ . M 3+ may be any trivalent cation, but preferred examples include Al 3+ or Cr 3+ , and more preferred is Al 3+ . A n- may be any anion, preferred examples OH - and CO 3 2- and the like. Accordingly, the general formula is at least M 2+ is Mg 2+, include M 3+ is Al 3+, A n-is OH - and / or CO preferably contains 3 2-. n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35. Such a raw material powder may be a commercially available layered double hydroxide product, or may be a raw material produced by a known method such as a liquid phase synthesis method using nitrate or chloride. The particle size of the raw material powder is not limited as long as a desired layered double hydroxide sintered body is obtained, but the volume-based D50 average particle size is preferably 0.1 to 1.0 μm, more preferably 0.00. 3 to 0.8 μm. This is because if the particle size of the raw material powder is too fine, the powder tends to aggregate, and if it is too large, the moldability becomes poor. In addition, before forming which will be described later, the layered double hydroxide powder may be calcined to obtain an oxide powder. The calcining temperature at this time is somewhat different depending on the constituent M 2+ and M 3+ , but is preferably 500 ° C. or lower, more preferably 380 to 460 ° C., in a region where the raw material particle size does not change significantly. In the production method according to the first aspect, the raw material powder preferably does not contain a binder and a pore former from the viewpoint of obtaining a highly dense layered double hydroxide sintered body.
（２）成形体の作製
原料粉末を成形して所望の形状を有する成形体を得る。好ましい形状の例としては、球状、円柱状、中空円柱状、ペレット状、ハニカム状、繊維状、メッシュ状、球に突起を設けた形状、球に窪みを設けた形状、及びそれらの組み合わせが挙げられる。成形は、所望の形状及び所望の相対密度を付与可能な成形手法を適宜選択して行えばよい。好ましい成形手法の一つとして加圧成形が挙げられる。加圧成形は、金型一軸プレスにより行ってもよいし、冷間等方圧加圧（ＣＩＰ）により行ってもよい。冷間等方圧加圧（ＣＩＰ）を用いる場合は原料粉末をゴム製容器中に入れて真空封じするか、あるいは予備成形したものを用いるのが好ましい。その他、スリップキャストや押出成形など、公知の方法で成形してもよく、成形方法については特に限定されない。ただし、原料粉末を仮焼して酸化物粉末とした場合は、乾式成形法に限られる。いずれにしても、成形は１００ｋｇｆ／ｃｍ２以上で、かつ、１０００ｋｇｆ／ｃｍ２未満の圧力で行われるのが好ましい。
(2) Production of molded body A raw material powder is molded to obtain a molded body having a desired shape. Examples of preferable shapes include spherical shapes, cylindrical shapes, hollow cylindrical shapes, pellet shapes, honeycomb shapes, fiber shapes, mesh shapes, shapes in which spheres are provided with protrusions, shapes in which spheres are provided with depressions, and combinations thereof. It is done. The molding may be performed by appropriately selecting a molding technique that can provide a desired shape and a desired relative density. One preferred molding technique is pressure molding. The pressure molding may be performed by a die uniaxial press or by cold isostatic pressing (CIP). In the case of using cold isostatic pressing (CIP), it is preferable to put the raw material powder in a rubber container and vacuum-seal it or use a preformed one. In addition, you may shape | mold by well-known methods, such as slip casting and extrusion molding, and it does not specifically limit about a shaping | molding method. However, when the raw material powder is calcined to obtain an oxide powder, it is limited to the dry molding method. In any case, the molding is 100 kgf / cm 2 or more, and is preferably carried out at a pressure of less than 1000 kgf / cm 2.
（３）含浸／焼成工程
成形体に対し、触媒前駆体溶液への含浸と焼成を行う。含浸及び焼成の順序は特に限定されないが、含浸を先に行う場合には含浸に先立ち成形体の水熱処理及び／又は仮焼を行う。すなわち（３ａ）成形体を水熱処理及び／又は仮焼し、触媒前駆体溶液に含浸させた後、焼成してもよいし、あるいは（３ｂ）成形体を焼成した後、触媒前駆体溶液に含浸させてもよい。また、上記（３ｂ）の場合であっても、成形体の焼成前に、成形体を水熱処理及び／又は仮焼してもよい。いずれにしても、この含浸／焼成工程により触媒前駆体を担持した酸化物焼成体を得ることができる。
(3) Impregnation / firing step Impregnation and firing of the catalyst precursor solution are performed on the compact. The order of impregnation and firing is not particularly limited, but when impregnation is performed first, hydrothermal treatment and / or calcination of the molded body is performed prior to impregnation. That is, (3a) the molded body may be hydrothermally treated and / or calcined and impregnated in the catalyst precursor solution, and then fired, or (3b) the molded body may be fired and then impregnated in the catalyst precursor solution. You may let them. Even in the case of (3b) above, the molded body may be subjected to hydrothermal treatment and / or calcination before firing of the molded body. In any case, a fired oxide body carrying the catalyst precursor can be obtained by this impregnation / firing step.
この水熱処理は成形体を水蒸気に曝すことにより行うことができ、好ましくは１００〜２００℃で行われる。この水熱処理を行うことで、後続の含浸／焼成工程に耐えうる保形性を成形体に付与することができる。水熱処理は１０分以上行われるのが好ましく、より好ましくは１〜２時間である。この水熱処理は密閉容器中で成型体を水と直接接しないように保持して行われるのが好ましい。密閉容器の例としてはテフロン製の密閉容器が挙げられ、より好ましくはその外側にステンレス製等のジャケットを備えた密閉容器である。水熱処理された成形体は自然脱水ないし乾燥させるのが好ましい。この自然脱水ないし乾燥は室温（例えば２０〜３０℃）で行えばよく、その場合の相対湿度は通常の室内環境における４０〜７０％の範囲内であれば問題はない。一方、仮焼もまた、後続の含浸／焼成工程に耐えうる保形性を成形体に付与するための工程であり、水熱処理に代えて又は水熱処理と共に採用可能である。この仮焼は４００〜６００℃の温度で行われるのが好ましい。この範囲の仮焼温度で０．５〜１０時間保持されるのが好ましく、より好ましくは１〜３時間である。また、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、上記仮焼温度に到達させるための昇温は１００℃／ｈ以下の速度で行われるのが好ましく、より好ましくは５〜７５℃／ｈであり、さらに好ましくは１０〜５０℃／ｈである。 This hydrothermal treatment can be performed by exposing the molded body to water vapor, and is preferably performed at 100 to 200 ° C. By performing this hydrothermal treatment, a shape-retaining property that can withstand the subsequent impregnation / firing step can be imparted to the molded body. The hydrothermal treatment is preferably performed for 10 minutes or more, more preferably 1 to 2 hours. This hydrothermal treatment is preferably carried out in a sealed container while holding the molded body so as not to come into direct contact with water. An example of the sealed container is a Teflon-made sealed container, and more preferably a sealed container having a jacket made of stainless steel or the like outside. The hydrothermally treated molded body is preferably dehydrated or dried. This natural dehydration or drying may be performed at room temperature (for example, 20 to 30 ° C.), and there is no problem as long as the relative humidity is within a range of 40 to 70% in a normal indoor environment. On the other hand, calcination is also a step for imparting shape retention to the molded body that can withstand the subsequent impregnation / firing step, and can be employed in place of or together with the hydrothermal treatment. This calcination is preferably performed at a temperature of 400 to 600 ° C. It is preferable to hold | maintain at the calcining temperature of this range for 0.5 to 10 hours, More preferably, it is 1 to 3 hours. Further, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the molded body, the temperature rise for reaching the calcining temperature is preferably performed at a rate of 100 ° C./h or less, More preferably, it is 5-75 degreeC / h, More preferably, it is 10-50 degreeC / h.
含浸に用いられる触媒前駆体溶液は、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された溶液（例えば水溶液）であり、焼成後の酸化物焼成体に、後続の還元処理工程で触媒金属に還元されることになる触媒前駆体（例えば金属イオン）を与えることができる。金属を含む化合物の例としては、塩化物、臭化物、ヨウ化物、硝酸塩、硫酸塩、リン酸塩等の金属塩の他、金属錯体等が挙げられる。溶媒は、上記化合物を溶解可能なものであれば特に制限されないが、水、アンモニア水、アセトン、アルコール類等が好ましく例示され、より好ましくは水及び／又はアンモニア水である。含浸後は、水や有機溶媒等により洗浄し、真空乾燥などにより乾燥してもよい。 The catalyst precursor solution used for impregnation includes at least one metal selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. A solution in which a compound is dissolved (for example, an aqueous solution), and a catalyst precursor (for example, metal ions) that can be reduced to a catalyst metal in a subsequent reduction treatment step can be provided to the calcined oxide calcined body. . Examples of the compound containing a metal include metal complexes such as chloride, bromide, iodide, nitrate, sulfate, phosphate and the like. The solvent is not particularly limited as long as it can dissolve the above compound, but water, aqueous ammonia, acetone, alcohols and the like are preferably exemplified, and more preferably water and / or aqueous ammonia. After the impregnation, the substrate may be washed with water or an organic solvent and dried by vacuum drying or the like.
焼成は４００〜８５０℃の温度で行われるのが好ましく、より好ましくは７００〜８００℃である。この範囲内の焼成温度で１時間以上保持されるのが好ましく、より好ましい保持時間は３〜１０時間である。また、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、上記焼成温度に到達させるための昇温は１００℃／ｈ以下の速度で行われるのが好ましく、より好ましくは５〜７５℃／ｈであり、さらに好ましくは１０〜５０℃／ｈである。したがって、昇温から降温（１００℃以下）に至るまでの全焼成時間は２０時間以上確保するのが好ましく、より好ましくは３０〜７０時間、さらに好ましくは３５〜６５時間である。 Firing is preferably performed at a temperature of 400 to 850 ° C, more preferably 700 to 800 ° C. It is preferable to hold | maintain for 1 hour or more with the calcination temperature in this range, and a more preferable holding time is 3 to 10 hours. Further, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the molded body, the temperature rise for reaching the firing temperature is preferably performed at a rate of 100 ° C./h or less. Preferably it is 5-75 degreeC / h, More preferably, it is 10-50 degreeC / h. Therefore, it is preferable to secure a total firing time from temperature increase to temperature decrease (100 ° C. or lower) of 20 hours or more, more preferably 30 to 70 hours, and further preferably 35 to 65 hours.
（４）還元処理工程
触媒前駆体を担持した酸化物焼成体に還元処理を施して上記金属を触媒として生成させる。還元処理は公知の手法に従って行えばよく、水素雰囲気又は真空下にて加熱することにより行ってもよいし、水素、ヒドラジン、ホルムアルデヒド、水素化ホウ素カリウム、水素化ホウ素ナトリウム等の還元剤で処理することにより行ってもよい。例えば、水素雰囲気又は真空下で還元処理を行う場合、触媒前駆体を担持した酸化物焼成体を水素雰囲気又は真空下にて１５０〜１８０℃で０．５時間程度処理することにより好ましく還元を行うことができる。
(4) Reduction treatment step The oxide calcined body carrying the catalyst precursor is subjected to a reduction treatment to produce the metal as a catalyst. The reduction treatment may be performed according to a known method, may be performed by heating in a hydrogen atmosphere or under vacuum, or is treated with a reducing agent such as hydrogen, hydrazine, formaldehyde, potassium borohydride, or sodium borohydride. It may be done by. For example, when the reduction treatment is performed in a hydrogen atmosphere or under vacuum, the oxide calcined body carrying the catalyst precursor is preferably reduced for about 0.5 hours at 150 to 180 ° C. in a hydrogen atmosphere or under vacuum. be able to.
（５）層状複水酸化物への再生工程
上記工程で得られた触媒が生成された酸化物焼成体を上述したｎ価の陰イオン（Ａｎ−）を含む水溶液中又はその直上に保持して層状複水酸化物へと再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る。なお、水溶液中に含まれる陰イオンは原料粉末中に含まれる陰イオンと同種の陰イオンとしてよいし、異なる種類の陰イオンとしてもよい。酸化物焼成体の水溶液中又は水溶液直上での保持は密閉容器内で水熱合成の手法により行われるのが好ましく、そのような密閉容器の例としてはテフロン製の密閉容器が挙げられ、より好ましくはその外側にステンレス製等のジャケットを備えた密閉容器である。層状複水酸化物化は、酸化物焼成体を２０℃以上２００℃未満で、少なくとも酸化物焼成体の一面が水溶液に接する状態に保持することにより行われるのが好ましく、より好ましい温度は５０〜１８０℃であり、さらに好ましい温度は１００〜１５０℃である。このような層状複水酸化物化温度で酸化物焼成体が１時間以上保持されるのが好ましく、より好ましくは２〜５０時間であり、さらに好ましくは５〜２０時間である。このような保持時間であると十分に層状複水酸化物への再生を進行させて異相が残るのを回避又は低減できる。なお、この保持時間は、長すぎても特に問題はないが、効率性を重視して適時設定すればよい。
(5) Regeneration step to layered double hydroxide The oxide calcined product in which the catalyst obtained in the above step is generated is held in or just above the aqueous solution containing the n-valent anion (A n− ) described above. Thus, a layered double hydroxide is regenerated to obtain a catalyst structure including a layered double hydroxide sintered body and a catalyst. The anion contained in the aqueous solution may be the same kind of anion as that contained in the raw material powder, or may be a different kind of anion. The holding of the oxide fired body in an aqueous solution or immediately above the aqueous solution is preferably performed by a hydrothermal synthesis method in a sealed container, and an example of such a sealed container is a sealed container made of Teflon, more preferably. Is a sealed container having a stainless steel jacket on the outside. The layered double hydroxide is preferably formed by maintaining the oxide fired body at 20 ° C. or more and less than 200 ° C. so that at least one surface of the oxide fired body is in contact with the aqueous solution, and a more preferable temperature is 50 to 180. And a more preferable temperature is 100 to 150 ° C. The oxide fired body is preferably held for 1 hour or more at such a layered double hydroxide formation temperature, more preferably 2 to 50 hours, and further preferably 5 to 20 hours. With such a holding time, it is possible to avoid or reduce the occurrence of a heterogeneous phase by sufficiently regenerating the layered double hydroxide. The holding time is not particularly problematic if it is too long, but it may be set in a timely manner with emphasis on efficiency.
層状複水酸化物への再生に使用するｎ価の陰イオンを含む水溶液の陰イオン種として空気中の二酸化炭素（炭酸イオン）を想定する場合は、イオン交換水を用いることが可能である。なお、密閉容器内の水熱処理の際には、酸化物焼成体を水溶液中に水没させてもよいし、治具を用いて少なくとも一面が水溶液に接する状態で処理を行ってもよい。少なくとも一面が水溶液に接する状態で処理した場合、完全水没と比較して余分な水分量が少ないので、その後の工程が短時間で済むことがある。ただし、水溶液が少なすぎるとクラックが発生しやすくなるため、焼成体重量と同等以上の水分を用いるのが好ましい。 When carbon dioxide (carbonate ion) in the air is assumed as an anion species of an aqueous solution containing an n-valent anion used for regeneration into a layered double hydroxide, ion-exchanged water can be used. In the hydrothermal treatment in the sealed container, the fired oxide body may be submerged in the aqueous solution, or the treatment may be performed in a state where at least one surface is in contact with the aqueous solution using a jig. When the treatment is performed in a state where at least one surface is in contact with the aqueous solution, the amount of excess water is small compared to complete submergence, so that the subsequent steps may be completed in a short time. However, if the amount of the aqueous solution is too small, cracks are likely to occur. Therefore, it is preferable to use moisture equal to or greater than the weight of the fired body.
ところで、この製法により得られる層状複水酸化物焼結体は余剰な水分を含みうるものである。そのような水分に富む層状複水酸化物焼結体をそのまま触媒担体として使用してもよいし、余剰の水分を除去してもよい。すなわち、本発明の方法は、必要に応じて、水分に富む層状複水酸化物焼結体から余剰の水分を除去する工程をさらに有していてもよい。この余剰の水分を除去する工程は、３００℃以下、除去工程の最高温度での推定相対湿度２５％以上の環境下で行われるのが好ましい。層状複水酸化物焼結体からの急激な水分の蒸発を防ぐため、室温より高い温度で脱水する場合は層状複水酸化物への再生工程で使用した密閉容器中に再び封入して行うことが好ましい。その場合の好ましい温度は５０〜２５０℃であり、さらに好ましくは１００〜２００℃である。また、脱水時のより好ましい相対湿度は２５〜７０％であり、さらに好ましくは４０〜６０％である。脱水を室温で行ってもよく、その場合の相対湿度は通常の室内環境における４０〜７０％の範囲内であれば問題はない。 By the way, the layered double hydroxide sintered body obtained by this manufacturing method can contain excessive moisture. Such a moisture-rich layered double hydroxide sintered body may be used as it is as a catalyst carrier, or excess moisture may be removed. That is, the method of the present invention may further include a step of removing excess moisture from the layered double hydroxide sintered body rich in moisture, if necessary. The step of removing excess water is preferably performed in an environment of 300 ° C. or lower and an estimated relative humidity of 25% or higher at the maximum temperature of the removal step. In order to prevent sudden evaporation of moisture from the layered double hydroxide sintered body, when dehydrating at a temperature higher than room temperature, re-enclose in the sealed container used in the regeneration process to layered double hydroxide. Is preferred. The preferable temperature in that case is 50-250 degreeC, More preferably, it is 100-200 degreeC. Moreover, the more preferable relative humidity at the time of spin-drying | dehydration is 25 to 70%, More preferably, it is 40 to 60%. Dehydration may be performed at room temperature, and there is no problem as long as the relative humidity is within a range of 40 to 70% in a normal indoor environment.
（ＩＩ）第二の態様による製造方法
本発明の第二の態様によれば、触媒構造体の製造は、（１）層状複水酸化物とバインダー及び／又は造孔材とを含む原料粉末を用意し、（２）原料粉末を成形し、（３）触媒前駆体溶液への含浸及び焼成を施し、（４）得られた酸化物焼成体に還元処理を施し、（５）酸化物焼成体を層状複水酸化物へ再生することにより行うことができる。この第二の態様による製造方法は、例えば相対密度が４０％以上かつ９０％未満といった、多孔性に富んだ層状複水酸化物焼結体を得るのに適している。
(II) Production Method According to Second Aspect According to the second aspect of the present invention, the production of the catalyst structure comprises (1) a raw material powder containing a layered double hydroxide and a binder and / or pore former. And (2) forming a raw material powder, (3) impregnating and firing the catalyst precursor solution, (4) subjecting the resulting oxide fired body to a reduction treatment, and (5) an oxide fired body. Can be regenerated to a layered double hydroxide. The production method according to the second aspect is suitable for obtaining a porous layered double hydroxide sintered body having a relative density of 40% or more and less than 90%, for example.
（１）原料粉末の用意
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる粉末を用意する。上記一般式において、Ｍ２＋は任意の２価の陽イオンでありうるが、好ましい例としてはＭｇ２＋、Ｃａ２＋及びＺｎ２＋が挙げられ、より好ましくはＭｇ２＋である。Ｍ３＋は任意の３価の陽イオンでありうるが、好ましい例としてはＡｌ３＋又はＣｒ３＋が挙げられ、より好ましくはＡｌ３＋である。Ａｎ−は任意の陰イオンでありうるが、好ましい例としてはＯＨ−及びＣＯ３ ２−が挙げられる。したがって、上記一般式は、少なくともＭ２＋がＭｇ２＋を、Ｍ３＋がＡｌ３＋を含み、Ａｎ−がＯＨ−及び／又はＣＯ３ ２−を含むのが好ましい。ｎは１以上の整数であるが、好ましくは１又は２である。ｘは０．１〜０．４であるが、好ましくは０．２〜０．３５である。このような原料粉末は市販の層状複水酸化物製品であってもよいし、硝酸塩や塩化物を用いた液相合成法等の公知の方法にて作製した原料であってもよい。原料粉末の粒径は、所望の層状複水酸化物焼結体が得られる限り限定されないが、体積基準Ｄ５０平均粒径が０．１〜１.０μｍであるのが好ましく、より好ましくは０．３〜０．８μｍである。原料粉末の粒径が細かすぎると粉末が凝集しやすく、大きすぎると成形性が悪くなるためである。なお、後述する成形前に、層状複水酸化物の粉末を仮焼して酸化物粉末としてもよい。この際の仮焼温度は、構成するＭ２＋及びＭ３＋によって多少の差があるが、５００℃以下が好ましく、より好ましくは３８０〜４６０℃とし、原料粒径が大きく変化しない領域で行う。
(1) Raw material powders prepared general formula: M 2+ 1-x M 3+ x (OH) 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent A n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4). . In the above general formula, M 2+ may be any divalent cation, and preferred examples include Mg 2+ , Ca 2+ and Zn 2+ , and more preferably Mg 2+ . M 3+ may be any trivalent cation, but preferred examples include Al 3+ or Cr 3+ , and more preferred is Al 3+ . A n- may be any anion, preferred examples OH - and CO 3 2- and the like. Accordingly, the general formula is at least M 2+ is Mg 2+, include M 3+ is Al 3+, A n-is OH - and / or CO preferably contains 3 2-. n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35. Such a raw material powder may be a commercially available layered double hydroxide product, or may be a raw material produced by a known method such as a liquid phase synthesis method using nitrate or chloride. The particle size of the raw material powder is not limited as long as a desired layered double hydroxide sintered body is obtained, but the volume-based D50 average particle size is preferably 0.1 to 1.0 μm, more preferably 0.00. 3 to 0.8 μm. This is because if the particle size of the raw material powder is too fine, the powder tends to aggregate, and if it is too large, the moldability becomes poor. In addition, before forming which will be described later, the layered double hydroxide powder may be calcined to obtain an oxide powder. The calcining temperature at this time is somewhat different depending on the constituent M 2+ and M 3+ , but is preferably 500 ° C. or lower, more preferably 380 to 460 ° C., in a region where the raw material particle size does not change significantly.
そして、層状複水酸化物からなる粉末と、バインダー及び／又は造孔材とを混合して、原料粉末を用意する。バインダーを含むことで層状複水酸化物焼結体に所望の形状を付与しやすくなる。また、造孔剤を含むことで層状複水酸化物焼結体に多孔性を付与しやすくなる。したがって、原料粉末はバインダー及び造孔材の両方を含むのが望ましい多孔質構造を実現できる点で好ましい。バインダーとしては有機バインダーを用いるのが好ましく、有機バインダーの好ましい例としては、メチルセルロース、ヒドロキシプロポキシルメチルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルセルロース、カルボキシルメチルセルロース、ポリビニルアルコール等を挙げることができる。有機バインダは、１種単独で又は２種以上を組み合わせて用いることができる。バインダーの添加量は層状複水酸化物の粉末１００質量部に対し２０質量部以下が好ましく、より好ましくは１０質量部以下である。好ましい造孔材としては、ＰＭＭＡ（ポリメタクリル酸メチル樹脂）粉末、グラファイト、小麦粉、澱粉、フェノール樹脂、ポリエチレン、ポリエチレンテレフタレート、発泡樹脂（アクリロニトリル系プラスチックバルーン）、吸水性樹脂等が挙げられる。造孔剤の添加量は狙いとする相対密度や多孔性に応じて適宜決定すればよく特に限定されないが、層状複水酸化物の粉末１００質量部に対し５０質量部以下が好ましく、より好ましくは２５質量部以下である。 And the powder which consists of a layered double hydroxide, a binder and / or a pore former are mixed, and raw material powder is prepared. By including a binder, it becomes easy to give a desired shape to the layered double hydroxide sintered body. Moreover, it becomes easy to provide porosity to the layered double hydroxide sintered body by including a pore forming agent. Therefore, the raw material powder is preferable in that a porous structure in which it is desirable to include both a binder and a pore former can be realized. An organic binder is preferably used as the binder, and preferred examples of the organic binder include methyl cellulose, hydroxypropoxyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol and the like. An organic binder can be used individually by 1 type or in combination of 2 or more types. The addition amount of the binder is preferably 20 parts by mass or less, more preferably 10 parts by mass or less with respect to 100 parts by mass of the layered double hydroxide powder. Preferable pore formers include PMMA (polymethyl methacrylate resin) powder, graphite, wheat flour, starch, phenol resin, polyethylene, polyethylene terephthalate, foamed resin (acrylonitrile plastic balloon), water absorbent resin and the like. The addition amount of the pore-forming agent is not particularly limited as long as it is appropriately determined depending on the target relative density and porosity, but is preferably 50 parts by mass or less, more preferably 100 parts by mass of the layered double hydroxide powder. 25 parts by mass or less.
（２）成形体の作製
原料粉末を成形して所望の形状を有する成形体を得る。好ましい形状の例としては、球状、円柱状、中空円柱状、ペレット状、ハニカム状、繊維状、メッシュ状、球に突起を設けた形状、球に窪みを設けた形状、及びそれらの組み合わせが挙げられる。成形は、所望の形状及び所望の相対密度を付与可能な成形手法を適宜選択して行えばよい。好ましい成形手法の一つとして加圧成形が挙げられる。加圧成形は、金型一軸プレスにより行ってもよいし、冷間等方圧加圧（ＣＩＰ）により行ってもよい。冷間等方圧加圧（ＣＩＰ）を用いる場合は原料粉末をゴム製容器中に入れて真空封じするか、あるいは予備成形したものを用いるのが好ましい。その他、スリップキャストや押出成形など、公知の方法で成形してもよく、成形方法については特に限定されない。ただし、原料粉末を仮焼して酸化物粉末とした場合は、乾式成形法に限られる。いずれにしても、成形は１００ｋｇｆ／ｃｍ２以上で、かつ、１０００ｋｇｆ／ｃｍ２未満の圧力で行われるのが好ましい。
(2) Production of molded body A raw material powder is molded to obtain a molded body having a desired shape. Examples of preferable shapes include spherical shapes, cylindrical shapes, hollow cylindrical shapes, pellet shapes, honeycomb shapes, fiber shapes, mesh shapes, shapes in which spheres are provided with protrusions, shapes in which spheres are provided with depressions, and combinations thereof. It is done. The molding may be performed by appropriately selecting a molding technique that can provide a desired shape and a desired relative density. One preferred molding technique is pressure molding. The pressure molding may be performed by a die uniaxial press or by cold isostatic pressing (CIP). In the case of using cold isostatic pressing (CIP), it is preferable to put the raw material powder in a rubber container and vacuum-seal it or use a preformed one. In addition, you may shape | mold by well-known methods, such as slip casting and extrusion molding, and it does not specifically limit about a shaping | molding method. However, when the raw material powder is calcined to obtain an oxide powder, it is limited to the dry molding method. In any case, the molding is 100 kgf / cm 2 or more, and is preferably carried out at a pressure of less than 1000 kgf / cm 2.
（３）含浸／焼成工程
成形体に対し、触媒前駆体溶液への含浸と焼成を行う。含浸及び焼成の順序は特に限定されないが、含浸を先に行う場合には含浸に先立ち成形体の仮焼を行う。すなわち（３ａ）成形体を仮焼し、触媒前駆体溶液に含浸させた後、焼成してもよいし、あるいは（３ｂ）成形体を焼成した後、触媒前駆体溶液に含浸させてもよい。いずれにしても、この含浸／焼成工程により触媒前駆体を担持した酸化物焼成体を得ることができる。
(3) Impregnation / firing step Impregnation and firing of the catalyst precursor solution are performed on the compact. The order of impregnation and firing is not particularly limited, but when the impregnation is performed first, the molded body is calcined prior to the impregnation. That is, (3a) the compact may be calcined and impregnated in the catalyst precursor solution and then fired, or (3b) the compact may be calcined and then impregnated in the catalyst precursor solution. In any case, a fired oxide body carrying the catalyst precursor can be obtained by this impregnation / firing step.
仮焼は、含浸を焼成よりも先に行う場合（すなわち上記（３ａ））においてのみ行われる工程であり、成形体中に含まれうるバインダー及び／又は造孔材等の有機分を除去して細孔を形成することができ、その結果、後続の含浸工程において細孔の内部に至るまで触媒前駆体を担持させることができる。この仮焼は５００〜６００℃の温度で行われるのが好ましい。この範囲の仮焼温度で０．５〜１０時間保持されるのが好ましく、より好ましくは１〜３時間である。また、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、上記仮焼温度に到達させるための昇温は１００℃／ｈ以下の速度で行われるのが好ましく、より好ましくは５〜７５℃／ｈであり、さらに好ましくは１０〜５０℃／ｈである。 The calcination is a process performed only when impregnation is performed prior to calcination (that is, the above (3a)), and organic components such as a binder and / or pore former that can be contained in the molded body are removed. The pores can be formed, so that the catalyst precursor can be supported up to the inside of the pores in the subsequent impregnation step. This calcination is preferably performed at a temperature of 500 to 600 ° C. It is preferable to hold | maintain at the calcining temperature of this range for 0.5 to 10 hours, More preferably, it is 1 to 3 hours. Further, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the molded body, the temperature rise for reaching the calcining temperature is preferably performed at a rate of 100 ° C./h or less, More preferably, it is 5-75 degreeC / h, More preferably, it is 10-50 degreeC / h.
含浸に用いられる触媒前駆体溶液は、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された溶液（例えば水溶液）であり、焼成後の酸化物焼成体に、後続の還元処理工程で触媒金属に還元されることになる触媒前駆体（例えば金属イオン）を与えることができる。金属を含む化合物の例としては、塩化物、臭化物、ヨウ化物、硝酸塩、硫酸塩、リン酸塩等の金属塩の他、金属錯体等が挙げられる。溶媒は、上記化合物を溶解可能なものであれば特に制限されないが、水、アンモニア水、アセトン、アルコール類等が好ましく例示され、より好ましくは水及び／又はアンモニア水である。含浸後は、水や有機溶媒等により洗浄し、真空乾燥などにより乾燥してもよい。 The catalyst precursor solution used for impregnation includes at least one metal selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. A solution in which a compound is dissolved (for example, an aqueous solution), and a catalyst precursor (for example, metal ions) that can be reduced to a catalyst metal in a subsequent reduction treatment step can be provided to the calcined oxide calcined body. . Examples of the compound containing a metal include metal complexes such as chloride, bromide, iodide, nitrate, sulfate, phosphate and the like. The solvent is not particularly limited as long as it can dissolve the above compound, but water, aqueous ammonia, acetone, alcohols and the like are preferably exemplified, and more preferably water and / or aqueous ammonia. After the impregnation, the substrate may be washed with water or an organic solvent and dried by vacuum drying or the like.
焼成は４００〜８５０℃の温度で行われるのが好ましく、より好ましくは５００〜８００℃である。この範囲内の焼成温度で１時間以上保持されるのが好ましく、より好ましい保持時間は３〜１０時間である。また、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、上記焼成温度に到達させるための昇温は１００℃／ｈ以下の速度で行われるのが好ましく、より好ましくは５〜７５℃／ｈであり、さらに好ましくは１０〜５０℃／ｈである。したがって、昇温から降温（１００℃以下）に至るまでの全焼成時間は２０時間以上確保するのが好ましく、より好ましくは３０〜７０時間、さらに好ましくは３５〜６５時間である。 Firing is preferably performed at a temperature of 400 to 850 ° C, more preferably 500 to 800 ° C. It is preferable to hold | maintain for 1 hour or more with the calcination temperature in this range, and a more preferable holding time is 3 to 10 hours. Further, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the molded body, the temperature rise for reaching the firing temperature is preferably performed at a rate of 100 ° C./h or less. Preferably it is 5-75 degreeC / h, More preferably, it is 10-50 degreeC / h. Therefore, it is preferable to secure a total firing time from temperature increase to temperature decrease (100 ° C. or lower) of 20 hours or more, more preferably 30 to 70 hours, and further preferably 35 to 65 hours.
（４）還元処理工程
触媒前駆体を担持した酸化物焼成体に還元処理を施して上記金属を触媒として生成させる。還元処理は公知の手法に従って行えばよく、水素雰囲気又は真空下にて加熱することにより行ってもよいし、水素、ヒドラジン、ホルムアルデヒド、水素化ホウ素カリウム、水素化ホウ素ナトリウム等の還元剤で処理することにより行ってもよい。例えば、水素雰囲気又は真空下で還元処理を行う場合、触媒前駆体を担持した酸化物焼成体を水素雰囲気又は真空下にて１５０〜１８０℃で０．５時間程度処理することにより好ましく還元を行うことができる。
(4) Reduction treatment step The oxide calcined body carrying the catalyst precursor is subjected to a reduction treatment to produce the metal as a catalyst. The reduction treatment may be performed according to a known method, may be performed by heating in a hydrogen atmosphere or under vacuum, or is treated with a reducing agent such as hydrogen, hydrazine, formaldehyde, potassium borohydride, or sodium borohydride. It may be done by. For example, when the reduction treatment is performed in a hydrogen atmosphere or under vacuum, the oxide calcined body carrying the catalyst precursor is preferably reduced for about 0.5 hours at 150 to 180 ° C. in a hydrogen atmosphere or under vacuum. be able to.
（５）層状複水酸化物への再生工程
上記工程で得られた触媒が生成された酸化物焼成体を上述したｎ価の陰イオン（Ａｎ−）を含む水溶液中又はその直上に保持して層状複水酸化物へと再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る。なお、水溶液中に含まれる陰イオンは原料粉末中に含まれる陰イオンと同種の陰イオンとしてよいし、異なる種類の陰イオンとしてもよい。酸化物焼成体の水溶液中又は水溶液直上での保持は密閉容器内で水熱合成の手法により行われるのが好ましく、そのような密閉容器の例としてはテフロン製の密閉容器が挙げられ、より好ましくはその外側にステンレス製等のジャケットを備えた密閉容器である。層状複水酸化物化は、酸化物焼成体を２０℃以上２００℃未満で、少なくとも酸化物焼成体の一面が水溶液に接する状態に保持することにより行われるのが好ましく、より好ましい温度は５０〜１８０℃であり、さらに好ましい温度は１００〜１５０℃である。このような層状複水酸化物化温度で酸化物焼成体が１時間以上保持されるのが好ましく、より好ましくは２〜５０時間であり、さらに好ましくは５〜２０時間である。このような保持時間であると十分に層状複水酸化物への再生を進行させて異相が残るのを回避又は低減できる。なお、この保持時間は、長すぎても特に問題はないが、効率性を重視して適時設定すればよい。
(5) Regeneration step to layered double hydroxide The oxide calcined product in which the catalyst obtained in the above step is generated is held in or just above the aqueous solution containing the n-valent anion (A n− ) described above. Thus, a layered double hydroxide is regenerated to obtain a catalyst structure including a layered double hydroxide sintered body and a catalyst. The anion contained in the aqueous solution may be the same kind of anion as that contained in the raw material powder, or may be a different kind of anion. The holding of the oxide fired body in an aqueous solution or immediately above the aqueous solution is preferably performed by a hydrothermal synthesis method in a sealed container, and an example of such a sealed container is a sealed container made of Teflon, more preferably. Is a sealed container having a stainless steel jacket on the outside. The layered double hydroxide is preferably formed by maintaining the oxide fired body at 20 ° C. or more and less than 200 ° C. so that at least one surface of the oxide fired body is in contact with the aqueous solution, and a more preferable temperature is 50 to 180. And a more preferable temperature is 100 to 150 ° C. The oxide fired body is preferably held for 1 hour or more at such a layered double hydroxide formation temperature, more preferably 2 to 50 hours, and further preferably 5 to 20 hours. With such a holding time, it is possible to avoid or reduce the occurrence of a heterogeneous phase by sufficiently regenerating the layered double hydroxide. The holding time is not particularly problematic if it is too long, but it may be set in a timely manner with emphasis on efficiency.
層状複水酸化物への再生に使用するｎ価の陰イオンを含む水溶液の陰イオン種として空気中の二酸化炭素（炭酸イオン）を想定する場合は、イオン交換水を用いることが可能である。なお、密閉容器内の水熱処理の際には、酸化物焼成体を水溶液中に水没させてもよいし、治具を用いて少なくとも一面が水溶液に接する状態で処理を行ってもよい。少なくとも一面が水溶液に接する状態で処理した場合、完全水没と比較して余分な水分量が少ないので、その後の工程が短時間で済むことがある。ただし、水溶液が少なすぎるとクラックが発生しやすくなるため、焼成体重量と同等以上の水分を用いるのが好ましい。 When carbon dioxide (carbonate ion) in the air is assumed as an anion species of an aqueous solution containing an n-valent anion used for regeneration into a layered double hydroxide, ion-exchanged water can be used. In the hydrothermal treatment in the sealed container, the fired oxide body may be submerged in the aqueous solution, or the treatment may be performed in a state where at least one surface is in contact with the aqueous solution using a jig. When the treatment is performed in a state where at least one surface is in contact with the aqueous solution, the amount of excess water is small compared to complete submergence, so that the subsequent steps may be completed in a short time. However, if the amount of the aqueous solution is too small, cracks are likely to occur. Therefore, it is preferable to use moisture equal to or greater than the weight of the fired body.
ところで、この製法により得られる層状複水酸化物焼結体は余剰な水分を含みうるものである。そのような水分に富む層状複水酸化物焼結体をそのまま触媒担体として使用してもよいし、余剰な水分を除去してもよい。すなわち、本発明の方法は、必要に応じて、上記工程で得られた水分に富む層状複水酸化物焼結体から余剰の水分を除去する工程をさらに有していてもよい。この余剰の水分を除去する工程は、３００℃以下、除去工程の最高温度での推定相対湿度２５％以上の環境下で行われるのが好ましい。層状複水酸化物焼結体からの急激な水分の蒸発を防ぐため、室温より高い温度で脱水する場合は層状複水酸化物への再生工程で使用した密閉容器中に再び封入して行うことが好ましい。その場合の好ましい温度は５０〜２５０℃であり、さらに好ましくは１００〜２００℃である。また、脱水時のより好ましい相対湿度は２５〜７０％であり、さらに好ましくは４０〜６０％である。脱水を室温で行ってもよく、その場合の相対湿度は通常の室内環境における４０〜７０％の範囲内であれば問題はない。 By the way, the layered double hydroxide sintered body obtained by this manufacturing method can contain excessive moisture. Such a layered double hydroxide sintered body rich in moisture may be used as a catalyst carrier as it is, or excess moisture may be removed. That is, the method of the present invention may further include a step of removing excess moisture from the moisture-rich layered double hydroxide sintered body obtained in the above step, if necessary. The step of removing excess water is preferably performed in an environment of 300 ° C. or lower and an estimated relative humidity of 25% or higher at the maximum temperature of the removal step. In order to prevent sudden evaporation of moisture from the layered double hydroxide sintered body, when dehydrating at a temperature higher than room temperature, re-enclose in the sealed container used in the regeneration process to layered double hydroxide. Is preferred. The preferable temperature in that case is 50-250 degreeC, More preferably, it is 100-200 degreeC. Moreover, the more preferable relative humidity at the time of spin-drying | dehydration is 25 to 70%, More preferably, it is 40 to 60%. Dehydration may be performed at room temperature, and there is no problem as long as the relative humidity is within a range of 40 to 70% in a normal indoor environment.
本発明を以下の例によってさらに具体的に説明する。 The present invention is more specifically described by the following examples.
例１：触媒構造体の作製
層状複水酸化物の一種のハイドロタルサイトを用いた触媒構造体である試料１〜１２を作製した。具体的には、前述した第一の態様による製造方法に従って試料１を作製する一方、前述した第二の製造方法に従って試料２〜７を作製した。また、比較のため、従来方法に従ってハイドロタルサイト圧粉体を用いた触媒構造体も作製した。各試料の具体的な作製手順は以下のとおりである。
Example 1 : Preparation of catalyst structure Samples 1 to 12 which were catalyst structures using a kind of hydrotalcite of a layered double hydroxide were prepared. Specifically, Sample 1 was prepared according to the manufacturing method according to the first aspect described above, while Samples 2 to 7 were prepared according to the second manufacturing method described above. For comparison, a catalyst structure using a hydrotalcite green compact was also prepared according to a conventional method. The specific production procedure for each sample is as follows.
（試料１）
原料粉末として、市販の層状複水酸化物であるハイドロタルサイト粉末（ＤＨＴ−６、協和化学工業株式会社製）を用意した。この原料粉末の組成はＭｇ２＋ ０．７５Ａｌ３＋ ０．２５（ＯＨ）２ＣＯ３ ２− ０．２５／２・ｍＨ２Ｏであった。この原料粉末を直径１６ｍｍの金型に充填し、５００ｋｇｆ／ｃｍ２で一軸プレス成形して、厚さ約２ｍｍの成形体を得た。外側にステンレス製ジャケットを備えたテフロン製の密閉容器に大気中でイオン交換水を封入した後、得られた成形体をイオン交換水と直接接しないように同じ容器に封入し、１８０℃で１時間保持した。得られた試料を２０〜３０℃、相対湿度が４０〜６０％程度の室内で自然脱水（乾燥）した。塩化金酸（ＨＡｕＣｌ４・ｘＨ２Ｏ）１．２４ｇをイオン交換水（５００ｍＬ）に溶解して得た溶液に、２５％アンモニア水を加え、得られた成形体を含浸させ、室温で２時間放置した。成形体を取り出し、脱イオン水で洗浄した後、減圧にて乾燥させた。得られた成形体をアルミナ鞘中で焼成した。この焼成は、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、１００℃／ｈ以下の速度で昇温を行い、７５０℃に達した時点で５時間保持した後、冷却を開始した。冷却中、１５０℃に達した時点で温度を維持し、脱気して真空雰囲気とした後、０．５時間保持し、焼成体に担持したＡｕを還元させた。得られた焼成体を、外側にステンレス製ジャケットを備えたテフロン製の密閉容器に大気中でイオン交換水と共に封入し、１００℃で５時間保持して水熱処理を施した。室温まで冷めた試料は余分な水分を含んでいるため、ろ紙等で軽く表面の水分を拭き取った。こうして得られた試料を２０〜３０℃、相対湿度が４０〜６０％程度の室内で自然脱水（乾燥）して試料１を得た。
(Sample 1)
A hydrotalcite powder (DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd.), which is a commercially available layered double hydroxide, was prepared as a raw material powder. The composition of this raw material powder was Mg 2+ 0.75 Al 3+ 0.25 (OH) 2 CO 3 2− 0.25 / 2 · mH 2 O. This raw material powder was filled in a metal mold having a diameter of 16 mm and uniaxial press-molded at 500 kgf / cm 2 to obtain a molded body having a thickness of about 2 mm. After ion-exchanged water is sealed in the air in a Teflon sealed container having a stainless steel jacket on the outside, the resulting molded product is sealed in the same container so as not to come into direct contact with the ion-exchanged water, and 1 at 180 ° C. Held for hours. The obtained sample was naturally dehydrated (dried) in a room at 20 to 30 ° C. and a relative humidity of about 40 to 60%. 25% ammonia water was added to a solution obtained by dissolving 1.24 g of chloroauric acid (HAuCl 4 × H 2 O) in ion-exchanged water (500 mL), and the resulting molded article was impregnated, and the mixture was allowed to stand at room temperature for 2 hours. I left it alone. The molded body was taken out, washed with deionized water, and then dried under reduced pressure. The obtained molded body was fired in an alumina sheath. In this firing, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking of the molded body, the temperature was raised at a rate of 100 ° C./h or less and held for 5 hours when the temperature reached 750 ° C. After that, cooling was started. During cooling, when the temperature reached 150 ° C., the temperature was maintained, deaerated to form a vacuum atmosphere, and held for 0.5 hour to reduce Au supported on the fired body. The obtained fired body was sealed in a Teflon sealed container having a stainless steel jacket on the outside together with ion-exchanged water in the atmosphere, and kept at 100 ° C. for 5 hours for hydrothermal treatment. Since the sample cooled to room temperature contained excess moisture, the moisture on the surface was gently wiped off with a filter paper or the like. The sample thus obtained was naturally dehydrated (dried) in a room at 20 to 30 ° C. and a relative humidity of about 40 to 60% to obtain Sample 1.
（試料２〜７）
原料粉末として、市販の層状複水酸化物であるハイドロタルサイト粉末（ＤＨＴ−６、協和化学工業株式会社製）を用意した。この粉末に、バインダーとしてのメチルセルロース（ハイドロタルサイト１００質量部に対し１０質量部）、造孔材であるＰＭＭＡ（ポリメタクリル酸メチル樹脂）粉末（ハイドロタルサイト１００質量部に対し２５質量部）を加え、混合した後、試料１と同様のプレス成形を行った。得られた成形体をアルミナ鞘中で仮焼した。この仮焼は、急激な昇温により水分や二酸化炭素が放出されて成形体が割れるのを防ぐため、１００℃／ｈ以下の速度で昇温を行い、５００℃に達した時点で５時間保持した後、冷却することにより行った。得られた試料は、方法１と同様に塩化金酸水溶液に含浸させた。含浸後の試料をアルミナ鞘中で焼成した。この焼成は、急激な昇温により水分や二酸化炭素が放出されて試料が割れるのを防ぐため、１００℃／ｈ以下の速度で昇温を行い、５００℃に達した時点で５時間保持した後、冷却を開始した。冷却中、１５０℃に達した時点で温度を維持し、脱気して真空雰囲気とした後、０．５時間保持し、焼成体に担持したＡｕを還元させた。得られた焼成体を、外側にステンレス製ジャケットを備えたテフロン製の密閉容器に大気中でイオン交換水と共に封入し、１００℃で５時間保持して水熱処理を施した。室温まで冷めた試料は余分な水分を含んでいるため、ろ紙等で軽く表面の水分を拭き取った。こうして得られた試料を２０〜３０℃、相対湿度が４０〜６０％程度の室内で自然脱水（乾燥）して試料７を得た。
(Samples 2-7)
A hydrotalcite powder (DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd.), which is a commercially available layered double hydroxide, was prepared as a raw material powder. To this powder, methylcellulose (10 parts by mass with respect to 100 parts by mass of hydrotalcite) as a binder and PMMA (polymethyl methacrylate resin) powder (25 parts by mass with respect to 100 parts by mass of hydrotalcite) as a pore former were added. In addition, after mixing, press molding similar to Sample 1 was performed. The obtained molded body was calcined in an alumina sheath. In this calcining, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking of the molded body, the temperature is raised at a rate of 100 ° C./h or less and held for 5 hours when reaching 500 ° C. Then, it was performed by cooling. The obtained sample was impregnated with an aqueous chloroauric acid solution in the same manner as in Method 1. The impregnated sample was fired in an alumina sheath. This firing is performed at a rate of 100 ° C./h or less and held for 5 hours when the temperature reaches 500 ° C. in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the sample. The cooling started. During cooling, when the temperature reached 150 ° C., the temperature was maintained, deaerated to form a vacuum atmosphere, and held for 0.5 hour to reduce Au supported on the fired body. The obtained fired body was sealed in a Teflon sealed container having a stainless steel jacket on the outside together with ion-exchanged water in the atmosphere, and kept at 100 ° C. for 5 hours for hydrothermal treatment. Since the sample cooled to room temperature contained excess moisture, the moisture on the surface was gently wiped off with a filter paper or the like. The sample thus obtained was naturally dehydrated (dried) in a room at 20 to 30 ° C. and a relative humidity of about 40 to 60% to obtain Sample 7.
また、ＰＭＭＡの添加量、仮焼温度及び焼成温度を適宜変更したこと以外は上記試料７と同様にして、表１に示される相対密度の試料２〜６を得た。 Moreover, samples 2 to 6 having the relative densities shown in Table 1 were obtained in the same manner as the sample 7 except that the addition amount of PMMA, the calcining temperature, and the firing temperature were appropriately changed.
（試料８〜１２‐比較）
塩化金酸（ＨＡｕＣｌ４・ｘＨ２Ｏ）１．２４ｇをイオン交換水（５００ｍＬ）に溶解して得た溶液に、ハイドロタルサイト［Ｍｇ６ Ａｌ２（ＯＨ）１６ＣＯ３］１０ｇ、２５％アンモニア水を加え、室温で２時間撹拌した。得られた沈殿物を吸引濾過し、脱イオン水で洗浄した後、減圧にて乾燥させた。乾燥させた沈殿物を、室温で真空乾燥後、真空下１５０℃で０．５時間処理することにより、ハイドロタルサイト表面固定化Ａｕ粒子触媒（Ａｕ／ＨＴ）を得た。得られた触媒を解砕して粉末にした後、試料１と同じ金型に充填し、表１に示される圧力で一軸プレス成形を行って、試料８〜１２の圧粉体を得た。
(Samples 8-12-comparison)
To a solution obtained by dissolving 1.24 g of chloroauric acid (HAuCl 4 .xH 2 O) in ion exchange water (500 mL), 10 g of hydrotalcite [Mg 6 Al 2 (OH) 16 CO 3 ], 25% ammonia Water was added and stirred at room temperature for 2 hours. The resulting precipitate was filtered with suction, washed with deionized water, and then dried under reduced pressure. The dried precipitate was vacuum dried at room temperature and then treated at 150 ° C. for 0.5 hours under vacuum to obtain a hydrotalcite surface-immobilized Au particle catalyst (Au / HT). The obtained catalyst was pulverized into powder, and then filled in the same mold as that of sample 1, and uniaxial press molding was performed at the pressure shown in Table 1 to obtain green compacts of samples 8-12.
例２：相対密度の測定
試料１〜１２の寸法及び重量から密度を求め、理論密度（２．０６ｇ／ｃｍ３，ＪＣＰＤＳカードＮｏ２２−０７００より）にて除して求めた。なお、この理論密度の２．０６ｇ／ｃｍ３なる数値はＡｕ粒子触媒の担持によって変化しないものと試算された。結果は表１に示されるとおりであった。
Example 2 Measurement of Relative Density Density was determined from the dimensions and weights of Samples 1 to 12 and divided by the theoretical density (2.06 g / cm 3 , from JCPDS card No 22-0700). In addition, the numerical value of 2.06 g / cm 3 of the theoretical density was estimated to be unchanged by the support of the Au particle catalyst. The results were as shown in Table 1.
例３：保形性の評価
トルエン（アルコール脱水素反応の溶媒）に試料１〜１２の触媒構造体を３時間浸した後、触媒構造体を回収した。回収前後における触媒構造体に形状変化を目視にて確認した。目視にて当初の形状を維持していると判断したものを「Ａ」と、当初の形状が維持されておらず崩れていると判断したものを「Ｂ」と評価した。結果は表１に示されるとおりであった。
Example 3 Evaluation of Shape Retention Property After immersing the catalyst structures of Samples 1 to 12 in toluene (a solvent for alcohol dehydrogenation reaction) for 3 hours, the catalyst structures were recovered. The change in shape of the catalyst structure before and after the recovery was visually confirmed. What was visually determined to maintain the original shape was evaluated as “A”, and what was determined to be broken because the original shape was not maintained was evaluated as “B”. The results were as shown in Table 1.
例４：結晶相の評価
Ｘ線回折装置（Ｄ８ ＡＤＶＡＮＣＥ、Ｂｕｌｋｅｒ ＡＸＳ社製）により、電圧：４０ｋＶ、電流値：４０ｍＡ、測定範囲：５〜７０°の測定条件で、試料１〜１２の結晶相を測定し、ＪＣＰＤＳカードＮＯ．３５−０９６５に記載されるハイドロタルサイトの回折ピークを用いて同定した。その結果、試料１〜１２はいずれもハイドロタルサイトに起因するピークが認められた。
Example 4 : Evaluation of crystal phase Crystal phase of samples 1 to 12 under the measurement conditions of voltage: 40 kV, current value: 40 mA, measurement range: 5-70 ° by X-ray diffractometer (D8 ADVANCE, manufactured by Bulker AXS) JCPDS card NO. It was identified using the hydrotalcite diffraction peak described in 35-0965. As a result, in each of Samples 1 to 12, peaks due to hydrotalcite were observed.
Claims (22)
前記層状複水酸化物焼結体上に担持され、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種を含んでなる触媒と、
を備えた、触媒構造体。 General formula: M 2+ 1-x M 3+ x (OH) in 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, A a layered double hydroxide sintered body having a layered double hydroxide as a main phase represented by n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4. ,
At least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag supported on the layered double hydroxide sintered body. A catalyst comprising
A catalyst structure comprising:
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる原料粉末を用意する工程と、
前記原料粉末を成形して、成形体を得る工程と、
前記成形体を水熱処理及び／又は仮焼し、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された触媒前駆体溶液に含浸させた後、焼成する、あるいは前記成形体を焼成した後、前記触媒前駆体溶液に含浸させ、それにより触媒前駆体を担持した酸化物焼成体を得る工程と、
前記触媒前駆体を担持した酸化物焼成体に還元処理を施して前記金属を触媒として生成させる工程と、
前記触媒が生成された酸化物焼成体を、ｎ価の陰イオンを含む水溶液中又はその直上に保持して層状複水酸化物へ再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る工程と、
を含む、方法。 A method for producing a catalyst structure, comprising:
General formula: M 2+ 1-x M 3+ x (OH) in 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, A a step of preparing a raw material powder composed of a layered double hydroxide represented by: n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4.
Molding the raw material powder to obtain a molded body;
The molded body is hydrothermally treated and / or calcined, and at least one selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. After impregnating the catalyst precursor solution in which the compound containing the metal is dissolved, firing, or firing the molded body, and then impregnating the catalyst precursor solution, thereby firing the oxide supporting the catalyst precursor. Obtaining a body;
A step of reducing the oxide calcined body carrying the catalyst precursor to produce the metal as a catalyst;
The oxide fired body in which the catalyst is generated is retained in or immediately above an aqueous solution containing an n-valent anion to be regenerated into a layered double hydroxide, whereby a layered double hydroxide sintered body and a catalyst are obtained. Obtaining a catalyst structure comprising:
Including a method.
一般式：Ｍ２＋ １−ｘＭ３＋ ｘ（ＯＨ）２Ａｎ− ｘ／ｎ・ｍＨ２Ｏ（式中、Ｍ２＋は２価の陽イオン、Ｍ３＋は３価の陽イオンであり、Ａｎ−はｎ価の陰イオン、ｎは１以上の整数、ｘは０．１〜０．４である）で表される層状複水酸化物からなる粉末と、バインダー及び／又は造孔材とを混合して、原料粉末を用意する工程と、
前記原料粉末を成形して、成形体を得る工程と、
前記成形体を仮焼し、Ｔｉ、Ｃｒ、Ｃｅ、Ｗ、Ｎｉ、Ｃｕ、Ｓｎ、Ｚｎ、Ｃｏ、Ｃｒ、Ｆｅ、Ａｕ、及びＡｇからなる群より選択される少なくとも１種の金属を含む化合物が溶解された触媒前駆体溶液に含浸させた後、焼成する、あるいは前記成形体を焼成した後、前記触媒前駆体溶液に含浸させ、それにより触媒前駆体を担持した酸化物焼成体を得る工程と、
前記触媒前駆体を担持した酸化物焼成体に還元処理を施して前記金属を触媒として生成させる工程と、
前記触媒が生成された酸化物焼成体を、ｎ価の陰イオンを含む水溶液中又はその直上に保持して層状複水酸化物へ再生し、それにより層状複水酸化物焼結体及び触媒を備えた触媒構造体を得る工程と、
を含む、方法。 A method for producing a catalyst structure, comprising:
General formula: M 2+ 1-x M 3+ x (OH) in 2 A n- x / n · mH 2 O ( wherein, M 2+ is a divalent cation, M 3+ is a trivalent cation, A n- is an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4) and a binder and / or pore former, And preparing a raw material powder,
Molding the raw material powder to obtain a molded body;
The molded body is calcined, and a compound containing at least one metal selected from the group consisting of Ti, Cr, Ce, W, Ni, Cu, Sn, Zn, Co, Cr, Fe, Au, and Ag. Impregnating the dissolved catalyst precursor solution and then calcining, or calcining the molded body and then impregnating the catalyst precursor solution, thereby obtaining an oxide calcined body carrying the catalyst precursor; ,
A step of reducing the oxide calcined body carrying the catalyst precursor to produce the metal as a catalyst;
The oxide fired body in which the catalyst is generated is retained in or immediately above an aqueous solution containing an n-valent anion to be regenerated into a layered double hydroxide, whereby a layered double hydroxide sintered body and a catalyst are obtained. Obtaining a catalyst structure comprising:
Including a method.
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| CN109925512A (en) * | 2019-01-07 | 2019-06-25 | 安徽理工大学 | A kind of novel aspirin two-dimensional nano load medicine and slow-releasing system |
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| CN111871426A (en) * | 2020-06-11 | 2020-11-03 | 安徽师范大学 | Pd nanoparticle-loaded nickel-iron double hydroxide nanosheet array structure material, preparation method and application thereof |
| JP7018569B1 (en) * | 2020-07-17 | 2022-02-14 | パナソニックＩｐマネジメント株式会社 | Electrode catalyst of water electrolysis cell, water electrolysis cell, and water electrolysis device |
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- 2014-03-05 JP JP2014043304A patent/JP2015167892A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109925512A (en) * | 2019-01-07 | 2019-06-25 | 安徽理工大学 | A kind of novel aspirin two-dimensional nano load medicine and slow-releasing system |
| CN110965076A (en) * | 2019-12-06 | 2020-04-07 | 吉林大学 | Preparation method of electrolytic water electrode with double-function three-dimensional layered core-shell structure |
| CN111197170A (en) * | 2020-02-24 | 2020-05-26 | 苏州科技大学 | Metal organic framework material/nickel-iron alloy composite electro-catalytic electrode and preparation method and application thereof |
| CN111871426A (en) * | 2020-06-11 | 2020-11-03 | 安徽师范大学 | Pd nanoparticle-loaded nickel-iron double hydroxide nanosheet array structure material, preparation method and application thereof |
| CN111871426B (en) * | 2020-06-11 | 2023-08-29 | 安徽师范大学 | Pd nanoparticle-supported nickel-iron double hydroxide nanosheet array structure material, preparation method and application thereof |
| JP7018569B1 (en) * | 2020-07-17 | 2022-02-14 | パナソニックＩｐマネジメント株式会社 | Electrode catalyst of water electrolysis cell, water electrolysis cell, and water electrolysis device |
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