JP5396118B2 - Internal combustion engine exhaust gas purification catalyst material and internal combustion engine exhaust gas purification catalyst - Google Patents
Internal combustion engine exhaust gas purification catalyst material and internal combustion engine exhaust gas purification catalyst Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims description 184
- 239000000463 material Substances 0.000 title claims description 74
- 238000002485 combustion reaction Methods 0.000 title claims description 62
- 238000000746 purification Methods 0.000 title claims description 59
- 229910052751 metal Inorganic materials 0.000 claims description 85
- 239000002184 metal Substances 0.000 claims description 85
- 229910052763 palladium Inorganic materials 0.000 claims description 59
- 229910052703 rhodium Inorganic materials 0.000 claims description 51
- 239000002131 composite material Substances 0.000 claims description 34
- 229910017493 Nd 2 O 3 Inorganic materials 0.000 claims description 32
- 229910021193 La 2 O 3 Inorganic materials 0.000 claims description 31
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 20
- 229910052697 platinum Inorganic materials 0.000 claims description 20
- RCFVMJKOEJFGTM-UHFFFAOYSA-N cerium zirconium Chemical compound [Zr].[Ce] RCFVMJKOEJFGTM-UHFFFAOYSA-N 0.000 claims description 15
- 239000011230 binding agent Substances 0.000 claims description 10
- 239000000919 ceramic Substances 0.000 claims description 9
- 239000007769 metal material Substances 0.000 claims description 9
- 239000011247 coating layer Substances 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 5
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910052684 Cerium Inorganic materials 0.000 claims description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims 1
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 85
- 239000010948 rhodium Substances 0.000 description 71
- 239000007789 gas Substances 0.000 description 65
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 36
- 239000000243 solution Substances 0.000 description 23
- 239000000843 powder Substances 0.000 description 21
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 16
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 15
- HBEQXAKJSGXAIQ-UHFFFAOYSA-N oxopalladium Chemical compound [Pd]=O HBEQXAKJSGXAIQ-UHFFFAOYSA-N 0.000 description 13
- 229910003445 palladium oxide Inorganic materials 0.000 description 13
- 230000003197 catalytic effect Effects 0.000 description 12
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 229910001220 stainless steel Inorganic materials 0.000 description 9
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 150000001875 compounds Chemical class 0.000 description 8
- 238000010304 firing Methods 0.000 description 8
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 8
- 238000001465 metallisation Methods 0.000 description 8
- CFYGEIAZMVFFDE-UHFFFAOYSA-N neodymium(3+);trinitrate Chemical compound [Nd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CFYGEIAZMVFFDE-UHFFFAOYSA-N 0.000 description 8
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000012153 distilled water Substances 0.000 description 5
- 239000010419 fine particle Substances 0.000 description 5
- 229910000510 noble metal Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 238000003756 stirring Methods 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000005191 phase separation Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 229910000420 cerium oxide Inorganic materials 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- UYXRCZUOJAYSQR-UHFFFAOYSA-N nitric acid;platinum Chemical compound [Pt].O[N+]([O-])=O UYXRCZUOJAYSQR-UHFFFAOYSA-N 0.000 description 2
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical group [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
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- 238000011056 performance test Methods 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
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Description
本発明は内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒に関し、より詳しくは、触媒成分として用いるＰｄＯ（酸化パラジウム）の金属化を抑制することにより、ＰｄＯの金属化に起因するＰｄ微粒子の粒成長（シンタリング）による触媒活性の低下が抑制され、従って、排気ガス中の酸素、ＨＣ（炭化水素）及びＣＯ（一酸化炭素）の濃度変化が激しく、Ａ／Ｆのウィンド幅が非常に広い、二輪車・汎用内燃機関等の排気ガス雰囲気で使用する場合であっても触媒活性の低下が生じにくい内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒に関する。 The present invention relates to an internal combustion engine exhaust gas purification catalyst material and an internal combustion engine exhaust gas purification catalyst. More specifically, the present invention results from the metallization of PdO by suppressing the metallization of PdO (palladium oxide) used as a catalyst component. Decrease in catalytic activity due to Pd fine particle growth (sintering) is suppressed, so that the concentration change of oxygen, HC (hydrocarbon) and CO (carbon monoxide) in the exhaust gas is severe, and the A / F window width The present invention relates to an internal combustion engine exhaust gas purification catalyst material and an internal combustion engine exhaust gas purification catalyst that are less likely to cause a decrease in catalytic activity even when used in an exhaust gas atmosphere of a motorcycle, a general-purpose internal combustion engine, or the like.
自動車等の内燃機関から排出される排気ガス中にはＨＣ、ＣＯ、ＮＯx（窒素酸化物）等の有害成分が含まれている。それで、従来から、これら有害成分を浄化して無害化する目的で三元触媒が用いられており、触媒活性成分として貴金属が用いられている。また、自動車排気ガスの規制強化に伴い、内燃機関排気ガス浄化用触媒の主要触媒活性成分である貴金属の白金及びロジウムの価格が高騰したことを受け、比較的安価なパラジウムを代替触媒活性成分として利用することにより排気ガス浄化用触媒のコストを削減することが検討され、提案されている（例えば、特許文献１、２、３参照。）。
The exhaust gas discharged from an internal combustion engine such as an automobile contains harmful components such as HC, CO, and NOx (nitrogen oxide). Therefore, conventionally, a three-way catalyst has been used for the purpose of purifying and detoxifying these harmful components, and noble metals have been used as catalytic active components. In response to the stricter regulations on automobile exhaust gas, the price of precious metals platinum and rhodium, which are the main catalytic active components of exhaust gas purification catalysts for internal combustion engines, has risen, and relatively inexpensive palladium is used as an alternative catalytic active component. It has been studied and proposed to reduce the cost of exhaust gas purifying catalysts by using them (see, for example,
通常の四輪車のようにストイキ〜リーンの状態で運転される割合が多い場合にはＰｄＯは比較的安定であり、金属に還元される程度は低いが、リッチな状態で運転される割合が多い上記のような二輪車・汎用内燃機関の排気ガス雰囲気条件では、還元性排気ガス成分によるＰｄＯの金属への還元を経由して粒成長による触媒活性の低下が生じることがパラジウム触媒利用の支障となっている。 PdO is relatively stable when the ratio of driving in a stoichiometric to lean state is high as in a normal four-wheeled vehicle, but the rate of reduction to metal is low, but the ratio of driving in a rich state Under the exhaust gas atmosphere conditions of many motorcycles and general-purpose internal combustion engines as described above, the catalytic activity is reduced due to grain growth through the reduction of PdO to the metal by the reducing exhaust gas component. It has become.
本発明は、上記のような事情に鑑みてなされたものであり、触媒成分として用いるＰｄＯの金属化を抑制することにより、ＰｄＯの金属化に起因するＰｄ微粒子の粒成長による触媒活性の低下が抑制され、従って、排気ガス中の酸素、ＨＣ及びＣＯの濃度変化が激しく、Ａ／Ｆのウィンド幅が非常に広い、二輪車・汎用内燃機関等の排気ガス雰囲気で使用する場合であっても触媒活性の低下が生じにくい内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒を提供することを目的としている。 The present invention has been made in view of the above circumstances, and by suppressing the metallization of PdO used as a catalyst component, the catalytic activity is reduced due to the particle growth of Pd fine particles resulting from the metallization of PdO. Therefore, even if it is used in an exhaust gas atmosphere such as a motorcycle or a general-purpose internal combustion engine, the concentration change of oxygen, HC and CO in the exhaust gas is severe and the A / F window width is very wide. An object of the present invention is to provide an internal combustion engine exhaust gas purification catalyst material and an internal combustion engine exhaust gas purification catalyst that are less likely to have a decrease in activity.
本発明者らは、上記の目的を達成するために鋭意検討した結果、高いＯＳＣ性能を有するセリウム−ジルコニウム系の複合酸化物であって酸化セリウムの質量が酸化ジルコニウムの質量よりも多い特定の複合酸化物材料の上に金属Ｐｄ又はＰｄ酸化物を分散させ、ＯＳＣ材の酸素ストレージ機能を利用してＡ／Ｆ変動時のＰｄＯの還元を抑制させることによりパラジウムの耐久安定性が向上すること、更に、熱安定性に劣る酸化セリウムの熱安定性を改善して上記の内燃機関排気ガスに長時間に曝されても高いＯＳＣ性能を維持できるように、このセリウム−ジルコニウム系複合酸化物に第３の元素Ｎｄと第４の元素Ｌａを固溶体化させてキャリアとすることにより、ＯＳＣ性能及び貴金属担持後の触媒浄化性能の低下が飛躍的に改善され、耐久性能が抜群に向上することを見いだし、本発明の内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒を完成した。 As a result of intensive studies to achieve the above object, the inventors of the present invention have found that a cerium-zirconium-based composite oxide having high OSC performance and a specific composite in which the mass of cerium oxide is larger than the mass of zirconium oxide. The durability stability of palladium is improved by dispersing metal Pd or Pd oxide on the oxide material and suppressing the reduction of PdO when the A / F fluctuates using the oxygen storage function of the OSC material. Furthermore, the cerium-zirconium-based composite oxide is further improved so that the thermal stability of cerium oxide, which is inferior in thermal stability, can be improved and high OSC performance can be maintained even when exposed to the exhaust gas of the internal combustion engine for a long time. By making the element Nd 3 and the fourth element La into a solid solution, a decrease in the OSC performance and the catalyst purification performance after supporting the noble metal is dramatically improved. It found that Hisashi performance is outstandingly improved, thereby completing the internal combustion engine exhaust gas purifying catalyst material and an internal combustion engine exhaust gas purifying catalyst of the present invention.
更に、上記のような特定のキャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分を有する内燃機関排気ガス浄化用触媒材料と、特定のキャリアに担持された金属Ｒｈ又はＲｈ酸化物からなる触媒成分を有する内燃機関排気ガス浄化用触媒材料、又は特定のキャリアに担持された金属Ｒｈ又はＲｈ酸化物からなる触媒成分及び金属Ｐｔ又はＰｔ酸化物からなる触媒成分と有する内燃機関排気ガス浄化用触媒材料とを特定の質量比で含む内燃機関排気ガス浄化用触媒材料とすることにより一層良好な内燃機関排気ガス浄化用触媒材料が得られることを見いだし、本発明の内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒を完成した。 Further, the catalyst material for exhaust gas purification of an internal combustion engine having a catalyst component made of metal Pd or Pd oxide supported on a specific carrier as described above, and metal Rh or Rh oxide supported on a specific carrier. Internal combustion engine exhaust gas purification catalyst material having a catalyst component, or an internal combustion engine exhaust gas purification having a catalyst component made of metal Rh or Rh oxide supported on a specific carrier and a catalyst component made of metal Pt or Pt oxide An internal combustion engine exhaust gas purification catalyst material containing a catalyst material at a specific mass ratio has been found to provide a better internal combustion engine exhaust gas purification catalyst material, and the internal combustion engine exhaust gas purification catalyst of the present invention Materials and internal combustion engine exhaust gas purification catalyst were completed.
即ち、本発明の内燃機関排気ガス浄化用触媒材料は、ＣｅＯ2の量が４５〜７０質量％であり、ＺｒＯ2の量が２０〜４５質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分とを有することを特徴とする。 That is, in the internal combustion engine exhaust gas purification catalyst material of the present invention, the amount of CeO 2 is 45 to 70% by mass, the amount of ZrO 2 is 20 to 45% by mass, and the amount of Nd 2 O 3 is 2 to 20%. A carrier composed of a cerium-zirconium composite oxide having a mass% of La 2 O 3 of 1 to 10 mass%, and a catalyst component composed of metal Pd or Pd oxide supported on the carrier. It is characterized by.
また、本発明の内燃機関排気ガス浄化用触媒は、セラミックス又は金属材料からなる担体の表面に形成された、上記の金属Ｐｄ又はＰｄ酸化物を含む内燃機関排気ガス浄化用触媒材料５０〜８０質量％と、耐熱性アルミナ系成分１０〜４０質量％と、バインダー材固形分５〜２０質量％とで構成されている触媒被覆層を有し、Ｐｄの担持量が金属換算で触媒１Ｌ当り０．７〜５．５ｇであることを特徴とする。 Moreover, the internal combustion engine exhaust gas purification catalyst of the present invention is 50 to 80 mass of the internal combustion engine exhaust gas purification catalyst material containing the above metal Pd or Pd oxide formed on the surface of a carrier made of ceramics or a metal material. %, A heat-resistant alumina-based component of 10 to 40% by mass, and a binder material solid content of 5 to 20% by mass, and the supported amount of Pd is 0. It is 7 to 5.5 g.
更に、本発明の内燃機関排気ガス浄化用触媒材料は、
（１）ＣｅＯ2の量が４５〜７０質量％であり、ＺｒＯ2の量が２０〜４５質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分とを有する内燃機関排気ガス浄化用触媒材料と、
（２）ＺｒＯ2の量が５０〜９５質量％であり、ＣｅＯ2の量が０〜４０質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された
（２−１）金属Ｒｈ又はＲｈ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量との質量比が金属換算でＰｄ／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料、又は
（２−２）金属Ｒｈ又はＲｈ酸化物からなる触媒成分及び金属Ｐｔ又はＰｔ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量とＰｔの量との質量比が金属換算で（Ｐｔ＋Ｐｄ）／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料、
とを含むことを特徴とする。
Further, the internal combustion engine exhaust gas purification catalyst material of the present invention,
(1) The amount of CeO 2 is 45 to 70% by mass, the amount of ZrO 2 is 20 to 45% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 is 1. An internal combustion engine exhaust gas purification catalyst material having a carrier composed of cerium-zirconium-based composite oxide of 10 mass% and a catalyst component composed of metal Pd or Pd oxide supported on the carrier;
(2) The amount of ZrO 2 is 50 to 95% by mass, the amount of CeO 2 is 0 to 40% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 is 1. 10% by mass of a carrier composed of a cerium-zirconium-based composite oxide and a catalyst component composed of (2-1) metal Rh or Rh oxide supported on the carrier, the amount of Pd and the amount of Rh The internal combustion engine exhaust gas purification catalyst material whose mass ratio to the amount is Pd / Rh = 1/1 to 20/1 in terms of metal, or (2-2) the catalyst component and metal Pt made of metal Rh or Rh oxide Or a Pt oxide catalyst component, and the mass ratio of the amount of Pd, the amount of Rh, and the amount of Pt is (Pt + Pd) / Rh = 1/1 to 20/1 in terms of metal Catalyst material for gas purification,
It is characterized by including.
また、本発明の内燃機関排気ガス浄化用触媒は、セラミックス又は金属材料からなる担体の表面に形成された、上記のＰｄ又はＰｄ酸化物と金属Ｒｈ又はＲｈ酸化物とを含む内燃機関排気ガス浄化用触媒材料又は上記のＰｄ又はＰｄ酸化物と金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とを含む内燃機関排気ガス浄化用触媒材料５０〜８０質量％と、耐熱性アルミナ系成分１０〜４０質量％と、バインダー材固形分５〜２０質量％とで構成されている触媒被覆層を有し、Ｐｄ、Ｒｈ及びＰｔの合計担持量が金属換算で触媒１Ｌ当り０．７〜６．５ｇであることを特徴とする。
Further, an internal combustion engine exhaust gas purification catalyst of the present invention is an internal combustion engine exhaust gas purification comprising the above Pd or Pd oxide and metal Rh or Rh oxide formed on the surface of a carrier made of ceramics or a metal material. Catalyst material for internal combustion engine exhaust gas purification containing the catalyst material or the above Pd or Pd oxide, metal Rh or Rh oxide and metal Pt or Pt oxide, and heat-
金属Ｐｄ又はＰｄ酸化物からなる触媒成分が特定のキャリアに担持されている本発明の内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒においては、触媒成分のＰｄＯの金属化が抑制されるので、ＰｄＯの金属化に起因するＰｄ微粒子の粒成長による触媒活性の低下が抑制され、従って、排気ガス中の酸素、ＨＣ及びＣＯの濃度変化が激しく、Ａ／Ｆのウィンド幅が非常に広い、二輪車・汎用内燃機関等の排気ガス雰囲気で使用する場合であっても触媒活性の低下が生じにくいので、本発明の内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒は二輪車・汎用内燃機関から排出される排気ガスに含まれる有害成分を浄化するのに好適に用いることができる。また、上記のような特定のキャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分と、特定のキャリアに担持された金属Ｒｈ又はＲｈ酸化物からなる触媒成分又は金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とからなる触媒成分を特定の質量比で用いることにより一層良好な内燃機関排気ガス浄化用触媒材料及び内燃機関排気ガス浄化用触媒が得られる。 In the internal combustion engine exhaust gas purification catalyst material and the internal combustion engine exhaust gas purification catalyst of the present invention in which a catalyst component made of metal Pd or Pd oxide is supported on a specific carrier, PdO metallization of the catalyst component is suppressed. Therefore, the decrease in catalytic activity due to the growth of Pd fine particles due to the metallization of PdO is suppressed, so that the concentration change of oxygen, HC and CO in the exhaust gas is severe, and the A / F window width is very Therefore, even when used in an exhaust gas atmosphere of a motorcycle, a general-purpose internal combustion engine, etc., the catalytic activity is unlikely to decrease, so the internal combustion engine exhaust gas purification catalyst material and the internal combustion engine exhaust gas purification catalyst of the present invention are It can be suitably used to purify harmful components contained in exhaust gas discharged from motorcycles and general-purpose internal combustion engines. Further, a catalyst component made of metal Pd or Pd oxide supported on a specific carrier as described above, and a catalyst component or metal Rh or Rh oxide made of metal Rh or Rh oxide supported on a specific carrier, An even better internal combustion engine exhaust gas purification catalyst material and internal combustion engine exhaust gas purification catalyst can be obtained by using a catalyst component made of metal Pt or Pt oxide at a specific mass ratio.
以下に、本発明の実施形態を具体的に説明する。
本発明の第一の態様の内燃機関排気ガス浄化用触媒材料はＣｅＯ2の量が４５〜７０質量％であり、ＺｒＯ2の量が２０〜４５質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分とを含有する。このようなキャリアは、焼成によりＣｅＯ2に変化し得るＣｅ化合物、焼成によりＺｒＯ2に変化し得るＺｒ化合物、焼成によりＮｄ2Ｏ3に変化し得るＮｄ化合物、及び焼成によりＬａ2Ｏ3に変化し得るＬａ化合物を含有する溶液のｐＨを６．０〜８．０程度に調整し、得られた沈殿物をろ過し、洗浄し、十分に乾燥させ、その後焼成することにより、例えば１０００℃で３時間焼成することにより得ることができる。
Embodiments of the present invention will be specifically described below.
In the internal combustion engine exhaust gas purification catalyst material according to the first aspect of the present invention, the amount of CeO 2 is 45 to 70% by mass, the amount of ZrO 2 is 20 to 45% by mass, and the amount of Nd 2 O 3 is 2%. a 20 wt%, La 2 O 3 amount is cerium from 1 to 10% by - a carrier consisting of zirconium complex oxide, and a catalyst component comprising a metal Pd or a Pd oxide supported on the carrier contains. Such a carrier is a Ce compound that can be changed to CeO 2 by firing, a Zr compound that can be changed to ZrO 2 by firing, an Nd compound that can be changed to Nd 2 O 3 by firing, and La 2 O 3 by firing. By adjusting the pH of the solution containing the La compound to about 6.0 to 8.0 and filtering the resulting precipitate, washing, thoroughly drying, and then calcining, for example at 1000 ° C. It can be obtained by baking for 3 hours.
本発明においては、ＰｄＯの金属化に起因するＰｄ微粒子の粒成長による触媒活性の低下を抑制し、従って、排気ガス中の酸素、未燃ガス成分のＨＣ及びＣＯの濃度変化が激しく、Ａ／Ｆのウィンド幅が非常に広い、二輪車・汎用内燃機関の排気ガス雰囲気で使用する場合であっても触媒活性の低下が生じにくくするために、金属Ｐｄ又はＰｄ酸化物からなる触媒成分を担持させるためのキャリア中のＣｅＯ2の量を４５〜７０質量％にし、ＺｒＯ2の量を２０〜４５質量％にし、ＣｅＯ2の質量をＺｒＯ2の質量よりも多くすることが好ましい。ＣｅＯ2の量が７０質量％を超え、或いはＺｒＯ2の量が２０質量％未満である場合には、活性種の性能が充分には発揮されず、また、高温時に、例えば９００℃以上の温度で担体の比表面積の低下が大きく、最終的に触媒の熱劣化を引き起こす傾向があるので好ましくない。ＣｅＯ2の量が４５質量％未満である場合には、ＰｄＯの還元を抑制する能力が低下する傾向があり、また、ＺｒＯ2の量が４５質量％を超える場合にはそれに応じてＣｅＯ2の量が減少するので好ましくない。 In the present invention, the decrease in the catalytic activity due to the growth of Pd fine particles due to the metallization of PdO is suppressed, and therefore the concentration change of oxygen in the exhaust gas, HC and CO of the unburned gas component is severe, and A / A catalyst component made of metal Pd or Pd oxide is supported in order to make it difficult for the catalyst activity to decrease even when used in an exhaust gas atmosphere of a motorcycle or general-purpose internal combustion engine with a very wide window width of F. Therefore, it is preferable that the amount of CeO 2 in the carrier is 45 to 70% by mass, the amount of ZrO 2 is 20 to 45% by mass, and the mass of CeO 2 is larger than the mass of ZrO 2 . When the amount of CeO 2 exceeds 70% by mass or the amount of ZrO 2 is less than 20% by mass, the performance of the active species is not sufficiently exhibited, and at a high temperature, for example, a temperature of 900 ° C. or higher. In this case, the specific surface area of the carrier is greatly reduced, and the catalyst tends to cause thermal deterioration of the catalyst. When the amount of CeO 2 is less than 45% by mass, the ability to suppress the reduction of PdO tends to be reduced, and when the amount of ZrO 2 exceeds 45% by mass, the CeO 2 Since the amount is reduced, it is not preferable.
本発明においては、金属Ｐｄ又はＰｄ酸化物からなる触媒成分を担持させるためのセリウム−ジルコニウム系複合酸化物キャリアは更にＮｄ2Ｏ3及びＬａ2Ｏ3を含有する。Ｎｄ2Ｏ3及びＬａ2Ｏ3を含むことにより、ＣｅＯ2の熱安定性が良くなり、セリウム−ジルコニウム系複合酸化物からなるキャリアのＯＳＣ性能及び貴金属担持後の触媒浄化性能の低下が飛躍的に改善され、耐久性能が抜群に向上する。この効果が達成されるためには、Ｎｄ2Ｏ3量が２質量％以上であり、Ｌａ2Ｏ3量が１質量％以上であることが必須である。しかし、Ｎｄ2Ｏ3量が２０質量％を超えたり、Ｌａ2Ｏ3量が１０質量％を超えたりする場合には、それに応じてＣｅＯ2及びＺｒＯ2の相対量が低下し、セリウム−ジルコニウム系複合酸化物からなるキャリアの特性が低下する傾向がある。 In the present invention, the cerium-zirconium-based composite oxide carrier for supporting the catalyst component made of metal Pd or Pd oxide further contains Nd 2 O 3 and La 2 O 3 . By including Nd 2 O 3 and La 2 O 3 , the thermal stability of CeO 2 is improved, and the OSC performance of the carrier made of a cerium-zirconium-based composite oxide and the catalyst purification performance after loading the noble metal are dramatically reduced. Improved durability and outstanding performance. In order to achieve this effect, it is essential that the amount of Nd 2 O 3 is 2% by mass or more and the amount of La 2 O 3 is 1% by mass or more. However, when the amount of Nd 2 O 3 exceeds 20% by mass or the amount of La 2 O 3 exceeds 10% by mass, the relative amounts of CeO 2 and ZrO 2 decrease accordingly, and cerium-zirconium There exists a tendency for the characteristic of the carrier which consists of a system complex oxide to fall.
本発明においては、触媒成分として貴金属の中では比較的安価な金属Ｐｄ又はＰｄ酸化物を用いる。これらの触媒成分の量はキャリアの質量を基準として金属Ｐｄ換算で０．３〜５質量％であることが好ましい。金属Ｐｄ換算で０．３質量％未満である場合には排気ガスに対する浄化性能が不十分となる傾向があり、逆に金属Ｐｄ換算で５質量％を超える場合には排気ガス浄化触媒のコストが高くなり、そのコストの増加に見合った効果の増強が得られない。 In the present invention, a relatively inexpensive metal Pd or Pd oxide is used as a catalyst component among noble metals. The amount of these catalyst components is preferably 0.3 to 5% by mass in terms of metal Pd based on the mass of the carrier. If the amount is less than 0.3% by mass in terms of metal Pd, the purification performance for exhaust gas tends to be insufficient. Conversely, if the amount exceeds 5% by mass in terms of metal Pd, the cost of the exhaust gas purification catalyst is low. It becomes high and the enhancement of the effect corresponding to the increase in the cost cannot be obtained.
また、本発明の第二の態様の内燃機関排気ガス浄化用触媒材料は
（１）上記の第一の態様の内燃機関排気ガス浄化用触媒材料、即ちＣｅＯ2の量が４５〜７０質量％であり、ＺｒＯ2の量が２０〜４５質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分とを有する内燃機関排気ガス浄化用触媒材料と、
（２）ＺｒＯ2の量が５０〜９５質量％であり、ＣｅＯ2の量が０〜４０質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された
（２−１）金属Ｒｈ又はＲｈ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量との質量比が金属換算でＰｄ／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料、又は
（２−２）金属Ｒｈ又はＲｈ酸化物からなる触媒成分及び金属Ｐｔ又はＰｔ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量とＰｔの量との質量比が金属換算で（Ｐｔ＋Ｐｄ）／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料
とを含み、一層良好な内燃機関排気ガス浄化用触媒材料である。
Further, the internal combustion engine exhaust gas purification catalyst material of the second aspect of the present invention is (1) the internal combustion engine exhaust gas purification catalyst material of the first aspect, that is, the amount of CeO 2 is 45 to 70% by mass. Yes, from a cerium-zirconium-based composite oxide in which the amount of ZrO 2 is 20 to 45% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 is 1 to 10% by mass. An internal combustion engine exhaust gas purification catalyst material comprising a carrier comprising: a catalyst component comprising a metal Pd or Pd oxide supported on the carrier;
(2) The amount of ZrO 2 is 50 to 95% by mass, the amount of CeO 2 is 0 to 40% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 is 1. 10% by mass of a carrier composed of a cerium-zirconium-based composite oxide and a catalyst component composed of (2-1) metal Rh or Rh oxide supported on the carrier, the amount of Pd and the amount of Rh The internal combustion engine exhaust gas purification catalyst material whose mass ratio to the amount is Pd / Rh = 1/1 to 20/1 in terms of metal, or (2-2) the catalyst component and metal Pt made of metal Rh or Rh oxide Or a Pt oxide catalyst component, and the mass ratio of the amount of Pd, the amount of Rh, and the amount of Pt is (Pt + Pd) / Rh = 1/1 to 20/1 in terms of metal Better catalytic material for exhaust gas purification of internal combustion engine It is.
本発明においては、金属Ｒｈ又はＲｈ酸化物からなる触媒成分、又は金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とからなる触媒成分を担持させるためのキャリアとしてＺｒＯ2の量が５０〜９５質量％であり、ＣｅＯ2の量が０〜４０質量％であり、Ｎｄ2Ｏ3量が２〜２０質量％であり、Ｌａ2Ｏ3量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアを用いるが、このようなキャリアは、焼成によりＺｒＯ2に変化し得るＺｒ化合物、焼成によりＣｅＯ2に変化し得るＣｅ化合物、焼成によりＮｄ2Ｏ3に変化し得るＮｄ化合物、及び焼成によりＬａ2Ｏ3に変化し得るＬａ化合物を含有する溶液のｐＨを６．０〜８．０程度に調整し、得られた沈殿物をろ過し、洗浄し、十分に乾燥させ、その後焼成することにより、例えば１０００℃で３時間焼成することにより得ることができる。 In the present invention, the amount of ZrO 2 is 50 to 95 as a carrier for supporting a catalyst component composed of metal Rh or Rh oxide, or a catalyst component composed of metal Rh or Rh oxide and metal Pt or Pt oxide. A cerium-zirconium-based composite in which the amount of CeO 2 is 0 to 40% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 is 1 to 10% by mass. A carrier made of an oxide is used. Such a carrier includes a Zr compound that can be changed to ZrO 2 by firing, a Ce compound that can be changed to CeO 2 by firing, an Nd compound that can be changed to Nd 2 O 3 by firing, And the pH of the solution containing the La compound that can be changed to La 2 O 3 by firing is adjusted to about 6.0 to 8.0, and the resulting precipitate is filtered, washed and sufficiently dried, Bake For example, it can obtain by baking at 1000 degreeC for 3 hours.
本発明においては、担持された金属Ｒｈ又はＲｈ酸化物からなる触媒成分、又は金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とからなる触媒成分が排気ガス中のＨＣ、ＣＯ、ＮＯxをより低温で且つより高活性に浄化でき、しかも耐熱性で最終的に触媒の熱劣化を防止し得るためには、触媒成分を担持させるためのキャリア中のＺｒＯ2の量を５０〜９５質量％にし、ＣｅＯ2の量を０〜４０質量％にする。即ち、ＣｅＯ2を含有しない場合でも本発明で目的とする効果を得ることができる。ＺｒＯ2の量が９５質量％を超えることは、それに応じてＮｄ2Ｏ3及びＬａ2Ｏ3の量が減少することになり、本発明で目的とする効果が低下する。逆に、ＺｒＯ2の量が５０質量％未満になるとキャリアの特性が低下する傾向がある。 In the present invention, the catalyst component composed of the supported metal Rh or Rh oxide, or the catalyst component composed of the metal Rh or Rh oxide and the metal Pt or Pt oxide further converts HC, CO, NOx in the exhaust gas. The amount of ZrO 2 in the carrier for supporting the catalyst component should be 50 to 95% by mass in order to be able to purify at a low temperature and with higher activity and to be heat resistant and finally prevent thermal deterioration of the catalyst. The amount of CeO 2 is 0 to 40% by mass. That is, even when CeO 2 is not contained, the intended effect of the present invention can be obtained. If the amount of ZrO 2 exceeds 95% by mass, the amounts of Nd 2 O 3 and La 2 O 3 will be reduced accordingly, and the intended effect of the present invention will be reduced. On the other hand, when the amount of ZrO 2 is less than 50% by mass, the carrier characteristics tend to deteriorate.
本発明においては、金属Ｒｈ又はＲｈ酸化物からなる触媒成分、又は金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とからなる触媒成分を担持させるためのセリウム−ジルコニウム系複合酸化物キャリアは更にＮｄ2Ｏ3及びＬａ2Ｏ3を含有する。Ｎｄ2Ｏ3及びＬａ2Ｏ3を含むことにより、ジルコニウム系複合酸化物からなるキャリアのＯＳＣ性能及び貴金属担持後の触媒浄化性能の低下が飛躍的に改善され、耐久性能が抜群に向上する。この効果が達成されるためには、Ｎｄ2Ｏ3量が２質量％以上であり、Ｌａ2Ｏ3量が１質量％以上であることが必須である。しかし、Ｎｄ2Ｏ3量が２０質量％を超えたり、Ｌａ2Ｏ3量が１０質量％を超えたりする場合には、それに応じてＣｅＯ2及びＺｒＯ2の相対量が低下し、ジルコニウム系複合酸化物からなるキャリアの特性が低下する傾向がある。 In the present invention, a cerium-zirconium based composite oxide carrier for supporting a catalyst component comprising a metal Rh or Rh oxide or a catalyst component comprising a metal Rh or Rh oxide and a metal Pt or Pt oxide is further provided. Contains Nd 2 O 3 and La 2 O 3 . By including Nd 2 O 3 and La 2 O 3 , the decrease in the OSC performance of the carrier composed of the zirconium-based composite oxide and the catalyst purification performance after supporting the noble metal is dramatically improved, and the durability performance is remarkably improved. In order to achieve this effect, it is essential that the amount of Nd 2 O 3 is 2% by mass or more and the amount of La 2 O 3 is 1% by mass or more. However, when the amount of Nd 2 O 3 exceeds 20% by mass or the amount of La 2 O 3 exceeds 10% by mass, the relative amounts of CeO 2 and ZrO 2 decrease accordingly, and the zirconium-based composite There exists a tendency for the characteristic of the carrier which consists of an oxide to fall.
上記のように、特定のキャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分と、特定のキャリアに担持された金属Ｒｈ又はＲｈ酸化物からなる触媒成分とを併用する場合には、Ｐｄ、Ｒｈ及びＰｔの各々の価格を考量すると、比較的安価で比較的高活性を維持し得るためには、Ｐｄの量とＲｈの量との質量比が金属換算でＰｄ／Ｒｈ＝１／１〜２０／１の範囲内にあることが好ましく、また、特定のキャリアに担持された金属Ｐｄ又はＰｄ酸化物からなる触媒成分と、特定のキャリアに担持された金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とからなる触媒成分とを併用する場合には、Ｐｄの量とＲｈの量とＰｔの量との質量比が金属換算で（Ｐｔ＋Ｐｄ）／Ｒｈ＝１／１〜２０／１であることが好ましい。 As described above, when a catalyst component made of metal Pd or Pd oxide supported on a specific carrier and a catalyst component made of metal Rh or Rh oxide supported on a specific carrier are used in combination, Pd In consideration of the prices of Rh and Pt, the mass ratio between the amount of Pd and the amount of Rh is Pd / Rh = 1/1 in terms of metal in order to maintain a relatively low cost and relatively high activity. It is preferable to be within a range of ˜20 / 1, and a catalyst component made of metal Pd or Pd oxide supported on a specific carrier, metal Rh or Rh oxide and metal Pt supported on a specific carrier, Or when using together the catalyst component which consists of Pt oxides, the mass ratio of the quantity of Pd, the quantity of Rh, and the quantity of Pt is (Pt + Pd) / Rh = 1 / 1-20 / 1 in metal conversion. Preferably there is.
本発明においては、担体に担持された従来の排気ガス浄化用三元触媒と同様に、セラミックス又は金属材料からなる担体上に上記の内燃機関排気ガス浄化用触媒材料の被覆層を担持させて用いる。このセラミックス又は金属材料からなる担体の形状は、特に限定されるものではないが、一般的にはハニカム、板等のモノリス形状や、ペレットの形状であり、好ましくはハニカム形状である。また、このような担体の材質としては、例えば、アルミナ、ムライト、コージライト等のセラミックスや、ステンレス等の金属材料が挙げられる。 In the present invention, like the conventional exhaust gas purifying three-way catalyst supported on the carrier, the coating layer of the above-mentioned internal combustion engine exhaust gas purifying catalyst material is supported on the carrier made of ceramic or metal material. . The shape of the carrier made of the ceramic or metal material is not particularly limited, but is generally a monolith shape such as a honeycomb or a plate, or a pellet shape, and preferably a honeycomb shape. Examples of the material of the carrier include ceramics such as alumina, mullite and cordierite, and metal materials such as stainless steel.
本発明において、セラミックス又は金属材料からなる担体上に上記の排気ガス浄化用触媒材料の被覆層を担持させて用いる場合には、セラミックス又は金属材料からなる担体の表面に、上記の内燃機関排気ガス浄化用触媒材料５０〜８０質量％と、耐熱性アルミナ系成分１０〜４０質量％と、バインダー材固形分５〜２０質量％とで構成される触媒被覆層を形成する。この場合に、触媒成分として金属Ｐｄ又はＰｄ酸化物を用いる上記第一の態様の場合にはＰｄの担持量が金属換算で触媒１Ｌ当り０．７〜５．５ｇとなるようにし、触媒成分として金属Ｐｄ又はＰｄ酸化物と金属Ｒｈ又はＲｈ酸化物とを用いるか、又は金属Ｐｄ又はＰｄ酸化物と金属Ｒｈ又はＲｈ酸化物と金属Ｐｔ又はＰｔ酸化物とを用いる上記第二の態様の場合にはＰｄとＲｈとＰｔとの合計担持量が金属換算で触媒１Ｌ当り０．７〜６．５ｇとなるようにすることが好ましい。 In the present invention, when the exhaust gas purification catalyst material coating layer is supported on a support made of ceramics or a metal material, the exhaust gas of the internal combustion engine is placed on the surface of the support made of a ceramic or metal material. A catalyst coating layer composed of 50 to 80% by mass of the purification catalyst material, 10 to 40% by mass of the heat-resistant alumina component, and 5 to 20% by mass of the binder material solid content is formed. In this case, in the case of the first embodiment using metal Pd or Pd oxide as the catalyst component, the supported amount of Pd is 0.7 to 5.5 g per liter of the catalyst in terms of metal, In the case of the second embodiment using metal Pd or Pd oxide and metal Rh or Rh oxide, or using metal Pd or Pd oxide and metal Rh or Rh oxide and metal Pt or Pt oxide The total supported amount of Pd, Rh, and Pt is preferably 0.7 to 6.5 g per liter of the catalyst in terms of metal.
本発明で用いることができる耐熱性アルミナ系成分は従来の排気ガス浄化用三元触媒において一般に用いられている如何なるものでもよいが、Ａｌ2Ｏ3、Ｌａ2Ｏ3−Ａｌ2Ｏ3複合酸化物、ＢａＯ−Ａｌ2Ｏ3複合酸化物、ＭｇＯ−Ａｌ2Ｏ3複合酸化物、ＺｒＯ2−ＣｅＯ2−Ａｌ2Ｏ3複合酸化物又はそれらの混合物であることが好ましい。 The heat-resistant alumina-based component that can be used in the present invention may be any one generally used in conventional three-way catalysts for exhaust gas purification, but Al 2 O 3 , La 2 O 3 -Al 2 O 3 composite oxidation And a BaO—Al 2 O 3 composite oxide, MgO—Al 2 O 3 composite oxide, ZrO 2 —CeO 2 —Al 2 O 3 composite oxide, or a mixture thereof.
以下に、実施例及び比較例に基づいて本発明を説明する。以下の実施例及び比較例において、各成分の相対量を示す質量部は分散媒、溶媒を除いた量を示している。 Below, this invention is demonstrated based on an Example and a comparative example. In the following examples and comparative examples, the parts by mass indicating the relative amounts of the components indicate the amounts excluding the dispersion medium and the solvent.
実施例１
硝酸セリウム（ＣｅＯ2換算量で）４８質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）４４質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）６質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）２質量部を５Ｌのフラスコに入れ、２０００ｍＬの純水を加え、１時間を撹拌して均一な溶液を調製した。
Example 1
48 parts by mass of cerium nitrate (in terms of CeO 2 ), 44 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 6 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and lanthanum nitrate (in terms of La 2 O 3 ) 2) 2 parts by mass were put into a 5 L flask, 2000 mL of pure water was added, and the mixture was stirred for 1 hour to prepare a uniform solution.
上記の溶液を撹拌しながら、１ＮのＮＨ4ＯＨ溶液をＰＨが７になるまで滴下し、得られた沈殿物をろ過し、洗浄し、８０℃で１５時間乾燥させ、その後１０００℃で３時間焼成して４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物を調製した。 While stirring the above solution, 1N NH 4 OH solution was added dropwise until the pH was 7, and the resulting precipitate was filtered, washed, dried at 80 ° C. for 15 hours, and then at 1000 ° C. for 3 hours. fired to prepare a 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3 composite oxide.
次いで、硝酸パラジウム溶液（Ｐｄ換算量で）２．０質量部を５００ｍＬのフラスコに入れ、１００ｍＬの純水を加えて均一に溶解させ、撹拌しながら上記の方法で得られた４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物９８質量部を添加して吸液させた。次いで１２０℃で６時間乾燥させ、５００℃で３時間焼成して、２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。 Next, 2.0 parts by mass of a palladium nitrate solution (in terms of Pd) was placed in a 500 mL flask, 100 mL of pure water was added and dissolved uniformly, and the 48CeO 2 -44ZrO 2 obtained by the above method with stirring. 98 parts by mass of -6Nd 2 O 3 -2La 2 O 3 composite oxide was added to absorb the liquid. Subsequently, it was dried at 120 ° C. for 6 hours and calcined at 500 ° C. for 3 hours to obtain 2 mass% Pd-supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3 catalyst material powder.
この２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末６０質量部、構造材として耐熱性ランタン−アルミナ粉末３０質量部、アルミナゾル系バインダー材（アルミナ換算量で）１０質量部及び蒸留水１８０質量部をボールミルに入れ、８時間粉砕してウォシュコート液を得た。 60 parts by mass of this 2% by mass Pd-supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3 catalyst material powder, 30 parts by mass of heat-resistant lanthanum-alumina powder as a structural material, alumina sol-based binder material (in terms of alumina) ) 10 parts by mass and 180 parts by mass of distilled water were placed in a ball mill and pulverized for 8 hours to obtain a washcoat solution.
次いで、ステンレス製メタルハニカム担体（３００セル、φ３０×３０Ｌ、容量２１ｃｃのテストピース）をそのウォシュコート液に浸漬した後、エアブローでセル中の余分のウォシュコート液を除去し、乾燥させ、５００℃で１時間焼成して触媒を得た。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算すると１Ｌ当り１．３２ｇであった。 Next, after immersing the stainless steel metal honeycomb carrier (300 cell, φ30 × 30L, capacity 21 cc test piece) in the washcoat solution, the excess washcoat solution in the cell was removed by air blow, dried, and 500 ° C. Was calcined for 1 hour to obtain a catalyst. The washcoat amount of this catalyst was 110 g per liter of the finished catalyst, and when converted to the amount of Pd supported, it was 1.32 g per liter.
実施例２
硝酸セリウム（ＣｅＯ2換算量で）４６質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）３６質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）１６質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）２質量部を使用した以外は実施例１に記載の方法と同様にして４６ＣｅＯ2−３６ＺｒＯ2−１６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物を調製した。また、実施例１に記載の方法と同様にして２質量％Ｐｄ担持４６ＣｅＯ2−３６ＺｒＯ2−１６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。更に、実施例１に記載の方法と同様にしてステンレス製メタルハニカム担体に担持させた。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算して１Ｌ当り１．３２ｇの触媒を得た。
Example 2
46 parts by mass of cerium nitrate (in terms of CeO 2 ), 36 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 16 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and lanthanum nitrate (in terms of La 2 O 3 ) 46CeO 2 -36ZrO 2 -16Nd 2 O 3 -2La 2 O 3 composite oxide was prepared in the same manner as described in Example 1 except that 2 parts by mass were used. Further, to obtain a 2 wt% Pd supported 46CeO 2 -36ZrO 2 -16Nd 2 O 3 -2La 2 O 3 catalyst material powder in the same manner as described in Example 1. Further, it was supported on a stainless steel metal honeycomb carrier in the same manner as described in Example 1. The amount of washcoat of this catalyst was 110 g per liter of the finished catalyst, and 1.32 g of catalyst per liter was obtained in terms of the amount of Pd supported.
比較例１
硝酸セリウム（ＣｅＯ2換算量で）４６質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）４９質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）５質量部を使用し、硝酸ネオジムは使用しなかった以外は実施例１に記載の方法と同様にして４６ＣｅＯ2−４９ＺｒＯ2−５Ｌａ2Ｏ3複合酸化物を調製した。また、実施例１に記載の方法と同様にして２質量％Ｐｄ担持４６ＣｅＯ2−４９ＺｒＯ2−５Ｌａ2Ｏ3触媒材料粉末を得た。更に、実施例１に記載の方法と同様にしてステンレス製メタルハニカム担体に担持させた。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算して１Ｌ当り１．３２ｇの触媒を得た。
Comparative Example 1
Use 46 parts by mass of cerium nitrate (in terms of CeO 2 ), 49 parts by mass of zirconium nitrate (in terms of ZrO 2 ) and 5 parts by mass of lanthanum nitrate (in terms of La 2 O 3 ), and do not use neodymium nitrate. A 46CeO 2 -49ZrO 2 -5La 2 O 3 composite oxide was prepared in the same manner as in Example 1 except that. Further, a 2% by mass Pd-supported 46CeO 2 -49ZrO 2 -5La 2 O 3 catalyst material powder was obtained in the same manner as described in Example 1. Further, it was supported on a stainless steel metal honeycomb carrier in the same manner as described in Example 1. The amount of washcoat of this catalyst was 110 g per liter of the finished catalyst, and 1.32 g of catalyst per liter was obtained in terms of the amount of Pd supported.
比較例２
硝酸セリウム（ＣｅＯ2換算量で）４６質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）２８質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）２４質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）２質量部を使用した以外は実施例１に記載の方法と同様にして４６ＣｅＯ2−２８ＺｒＯ2−２４Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物を調製した。また、実施例１に記載の方法と同様にして２質量％Ｐｄ担持４６ＣｅＯ2−２８ＺｒＯ2−２４Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。更に、実施例１に記載の方法と同様にしてステンレス製メタルハニカム担体に担持させた。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算して１Ｌ当り１．３２ｇの触媒を得た。
Comparative Example 2
46 parts by mass of cerium nitrate (in terms of CeO 2 ), 28 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 24 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and lanthanum nitrate (in terms of La 2 O 3 ) 46CeO 2 -28ZrO 2 -24Nd 2 O 3 -2La 2 O 3 composite oxide was prepared in the same manner as described in Example 1 except that 2 parts by mass was used. Further, a 2% by mass Pd-supported 46CeO 2 -28ZrO 2 -24Nd 2 O 3 -2La 2 O 3 catalyst material powder was obtained in the same manner as described in Example 1. Further, it was supported on a stainless steel metal honeycomb carrier in the same manner as described in Example 1. The amount of washcoat of this catalyst was 110 g per liter of the finished catalyst, and 1.32 g of catalyst per liter was obtained in terms of the amount of Pd supported.
比較例３
硝酸セリウム（ＣｅＯ2換算量で）３０質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）６０質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）８質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）２質量部を使用した以外は実施例１に記載の方法と同様にして３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物を調製した。また、実施例１に記載の方法と同様にして２質量％Ｐｄ担持３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。更に、実施例１に記載の方法と同様にしてステンレス製メタルハニカム担体に担持させた。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算して１Ｌ当り１．３２ｇの触媒を得た。
Comparative Example 3
30 parts by mass of cerium nitrate (in terms of CeO 2 ), 60 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 8 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and lanthanum nitrate (in terms of La 2 O 3 ) 30) CeO 2 -60ZrO 2 -8Nd 2 O 3 -2La 2 O 3 composite oxide was prepared in the same manner as described in Example 1 except that 2 parts by mass was used. Further, to obtain a 2 wt% Pd supported 30CeO 2 -60ZrO 2 -8Nd 2 O 3 -2La 2 O 3 catalyst material powder in the same manner as described in Example 1. Further, it was supported on a stainless steel metal honeycomb carrier in the same manner as described in Example 1. The amount of washcoat of this catalyst was 110 g per liter of the finished catalyst, and 1.32 g of catalyst per liter was obtained in terms of the amount of Pd supported.
比較例４
硝酸セリウム（ＣｅＯ2換算量で）４６質量部及び硝酸ジルコニウム（ＺｒＯ2換算量で）５４質量部を使用し、硝酸ネオジム及び硝酸ランタンを使用しなかった以外は実施例１に記載の方法と同様にして４６ＣｅＯ2−５４ＺｒＯ2複合酸化物を調製した。また、実施例１に記載の方法と同様にして２質量％Ｐｄ担持４６ＣｅＯ2−５４ＺｒＯ2触媒材料粉末を得た。更に、実施例１に記載の方法と同様にしてステンレス製メタルハニカム担体に担持させた。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算して１Ｌ当り１．３２ｇの触媒を得た。
Comparative Example 4
Similar to the method described in Example 1 except that 46 parts by mass of cerium nitrate (in terms of CeO 2 ) and 54 parts by mass of zirconium nitrate (in terms of ZrO 2 ) were used, and neodymium nitrate and lanthanum nitrate were not used. Thus, a 46CeO 2 -54ZrO 2 composite oxide was prepared. Further, a 2% by mass Pd-supported 46CeO 2 -54ZrO 2 catalyst material powder was obtained in the same manner as described in Example 1. Further, it was supported on a stainless steel metal honeycomb carrier in the same manner as described in Example 1. The amount of washcoat of this catalyst was 110 g per liter of the finished catalyst, and 1.32 g of catalyst per liter was obtained in terms of the amount of Pd supported.
実施例３
硝酸セリウム（ＣｅＯ2換算量で）３０質量部、硝酸ジルコニウム（ＺｒＯ2換算量で）６０質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）８質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）２質量部を使用した以外は実施例１に記載の方法と同様にして３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物を調製した。
Example 3
30 parts by mass of cerium nitrate (in terms of CeO 2 ), 60 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 8 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and lanthanum nitrate (in terms of La 2 O 3 ) 30) CeO 2 -60ZrO 2 -8Nd 2 O 3 -2La 2 O 3 composite oxide was prepared in the same manner as described in Example 1 except that 2 parts by mass was used.
硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部を５００ｍＬのフラスコに入れ、１００ｍＬの純水を加えて均一に溶解させ、撹拌しながら、上記で調製した３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3複合酸化物５０質量部と耐熱性ランタン−アルミナ複合酸化物４９．４質量部との混合粉末を添加して吸液させた。次いで１２０℃で６時間乾燥させ、５００℃で３時間焼成して０．６質量％Ｒｈ担持３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。
Add 0.6 parts by mass of rhodium nitrate solution (in terms of Rh) into a 500 mL flask, add 100 mL of pure water to dissolve uniformly, and while stirring, prepare 30 CeO 2 -60ZrO 2 -8Nd 2 O prepared above. 3 -2La 2 O 3
実施例１に記載の方法と同様にして調製した２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末６０質量部、上記の０．６質量％Ｒｈ担持３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末３０質量部、アルミナゾル系バインダー材（アルミナ換算量で）１０質量部及び蒸留水１８０質量部をボールミルに入れ、８時間粉砕してウォシュコート液を得た。
2 wt% Pd supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3
次いで、ステンレス製メタルハニカム担体（３００セル、φ３０×３０Ｌ、容量２１ｃｃのテストピース）をそのウォシュコート液に浸漬した後、エアブローでセル中の余分のウォシュコート液を除去し、乾燥させ、５００℃で１時間焼成して触媒を得た。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算すると１Ｌ当り１．３２ｇ、Ｒｈの担持量に換算すると１Ｌ当り０．２０ｇであった。 Next, after immersing the stainless steel metal honeycomb carrier (300 cell, φ30 × 30L, capacity 21 cc test piece) in the washcoat solution, the excess washcoat solution in the cell was removed by air blow, dried, and 500 ° C. Was calcined for 1 hour to obtain a catalyst. The washcoat amount of this catalyst was 110 g per liter of the finished catalyst. When converted to the amount of Pd supported, it was 1.32 g per liter, and when converted to the amount of Rh supported, it was 0.20 g per liter.
実施例４
硝酸ジルコニウム（ＺｒＯ2換算量で）８８．５質量部、硝酸ネオジム（Ｎｄ2Ｏ3換算量で）１０質量部及び硝酸ランタン（Ｌａ2Ｏ3換算量で）１．５質量部を使用し、硝酸セリウムを使用しなかった以外は実施例１に記載の方法と同様にして８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3複合酸化物を調製した。
Example 4
Using 88.5 parts by mass of zirconium nitrate (in terms of ZrO 2 ), 10 parts by mass of neodymium nitrate (in terms of Nd 2 O 3 ) and 1.5 parts by mass of lanthanum nitrate (in terms of La 2 O 3 ), An 88.5ZrO 2 -10Nd 2 O 3 -1.5La 2 O 3 composite oxide was prepared in the same manner as described in Example 1 except that cerium nitrate was not used.
硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部を５００ｍＬのフラスコに入れ、１００ｍＬの純水を加えて均一に溶解させ、撹拌しながら、上記で調製した８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3複合酸化物５０質量部と耐熱性ランタン−アルミナ複合酸化物４９．４質量部との混合粉末を添加して吸液させた。次いで１２０℃で６時間乾燥させ、５００℃で３時間焼成して０．６質量％Ｒｈ担持８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3触媒材料粉末を得た。 Add 0.6 parts by mass of rhodium nitrate solution (in terms of Rh) into a 500 mL flask, add 100 mL of pure water to dissolve uniformly, and while stirring, 88.5ZrO 2 -10Nd 2 O 3 A mixed powder of -1.5 La 2 O 3 composite oxide (50 parts by mass) and heat-resistant lanthanum-alumina composite oxide (49.4 parts by mass) was added to absorb the liquid. Subsequently, it was dried at 120 ° C. for 6 hours, and calcined at 500 ° C. for 3 hours to obtain a 0.6% by mass Rh-supported 88.5ZrO 2 -10Nd 2 O 3 -1.5La 2 O 3 catalyst material powder.
実施例１に記載の方法と同様にして調製した２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末６０質量部、上記の０．６質量％Ｒｈ担持８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3触媒材料粉末３０質量部、アルミナゾル系バインダー材（アルミナ換算量で）１０質量部及び蒸留水１８０質量部をボールミルに入れ、８時間粉砕してウォシュコート液を得た。
2 wt% Pd supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3
次いで、ステンレス製メタルハニカム担体（３００セル、φ３０×３０Ｌ、容量２１ｃｃのテストピース）をそのウォシュコート液に浸漬した後、エアブローでセル中の余分のウォシュコート液を除去し、乾燥させ、５００℃で１時間焼成して触媒を得た。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算すると１Ｌ当り１．３２ｇ、Ｒｈの担持量に換算すると１Ｌ当り０．２０ｇであった。 Next, after immersing the stainless steel metal honeycomb carrier (300 cell, φ30 × 30L, capacity 21 cc test piece) in the washcoat solution, the excess washcoat solution in the cell was removed by air blow, dried, and 500 ° C. Was calcined for 1 hour to obtain a catalyst. The washcoat amount of this catalyst was 110 g per liter of the finished catalyst. When converted to the amount of Pd supported, it was 1.32 g per liter, and when converted to the amount of Rh supported, it was 0.20 g per liter.
実施例５
硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部の代わりに硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部及び白金の硝酸溶液（Ｐｔ換算量で）１．２質量部を用いた以外は実施例３に記載の方法と同様にして０．６質量％Ｒｈ且つ１．２質量％Ｐｔ担持３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末を得た。
Example 5
Instead of 0.6 parts by mass of rhodium nitrate solution (in terms of Rh), 0.6 parts by mass of rhodium nitrate solution (in terms of Rh) and 1.2 parts by mass of platinum nitric acid solution (in terms of Pt) were used. except gained 0.6 wt% Rh and 1.2 wt% Pt supported 30CeO 2 -60ZrO 2 -8Nd 2 O 3 -2La 2 O 3 catalyst material powder in the same manner as described in example 3.
実施例１に記載の方法と同様にして調製した２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末６０質量部、上記の０．６質量％Ｒｈ且つ１．２質量％Ｐｔ担持３０ＣｅＯ2−６０ＺｒＯ2−８Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末３０質量部、アルミナゾル系バインダー材（アルミナ換算量で）１０質量部及び蒸留水１８０質量部を用いた以外は実施例３に記載の方法と同様にして触媒を調製した。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算すると１Ｌ当り１．３２ｇ、Ｐｔの担持量に換算すると１Ｌ当り０．４０ｇ、Ｒｈの担持量に換算すると１Ｌ当り０．２０ｇであった。
2 wt% Pd supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3
実施例６
硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部の代わりに硝酸ロジウム溶液（Ｒｈ換算量で）０．６質量部及び白金の硝酸溶液（Ｐｔ換算量で）１．２質量部を用いた以外は実施例４に記載の方法と同様にして０．６質量％Ｒｈ且つ１．２質量％Ｐｔ担持８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3触媒材料粉末を得た。
Example 6
Instead of 0.6 parts by mass of rhodium nitrate solution (in terms of Rh), 0.6 parts by mass of rhodium nitrate solution (in terms of Rh) and 1.2 parts by mass of platinum nitric acid solution (in terms of Pt) were used. Except for the above, a 0.6% by mass Rh and 1.2% by mass Pt-supported 88.5ZrO 2 -10Nd 2 O 3 -1.5La 2 O 3 catalyst material powder was obtained in the same manner as described in Example 4.
実施例１に記載の方法と同様にして調製した２質量％Ｐｄ担持４８ＣｅＯ2−４４ＺｒＯ2−６Ｎｄ2Ｏ3−２Ｌａ2Ｏ3触媒材料粉末６０質量部、上記の０．６質量％Ｒｈ且つ１．２質量％Ｐｔ担持８８．５ＺｒＯ2−１０Ｎｄ2Ｏ3−１．５Ｌａ2Ｏ3触媒材料粉末３０質量部、アルミナゾル系バインダー材（アルミナ換算量で）１０質量部及び蒸留水１８０質量部を用いた以外は実施例３に記載の方法と同様にして触媒を調製した。この触媒のウォシュコート量は完成触媒１Ｌ当り１１０ｇであり、Ｐｄの担持量に換算すると１Ｌ当り１．３２ｇ、Ｐｔの担持量に換算すると１Ｌ当り０．４０ｇ、Ｒｈの担持量に換算すると１Ｌ当り０．２０ｇであった。
2 wt% Pd supported 48CeO 2 -44ZrO 2 -6Nd 2 O 3 -2La 2 O 3
＜性能試験＞
実施例１〜６及び比較例１〜４で調製したそれぞれの触媒を９００℃に保持した電気炉に入れ、１体積％ＣＯ−Ｎ2混合ガスを２０Ｌ／ｍｉｎで流して２４時間熱処理し、その後室温まで冷却した。次いで、モデルガス中のＨＣ、ＣＯ及びＮＯ（酸化窒素が４００℃で低減される割合（浄化率）及び５０％浄化率に到達する温度〔Ｔ−５０（℃）〕を測定して、各々の触媒の三元浄化性能を評価した。評価条件は下記の通りであった。それらの結果は第１表に示す通りであった。
<Performance test>
The respective catalysts prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were put into an electric furnace maintained at 900 ° C., and heat-treated for 24 hours by flowing a 1% by volume CO—N 2 mixed gas at 20 L / min. Cooled to room temperature. Next, HC, CO, and NO in the model gas (the rate at which nitric oxide is reduced at 400 ° C. (purification rate) and the temperature at which the 50% purification rate is reached [T-50 (° C.)] are measured. The three-way purification performance of the catalyst was evaluated under the following conditions, and the results are shown in Table 1.
モデルガス組成：ＣＯ:０．３％、Ｃ3Ｈ6：１０００ｐｐｍ、ＮＯ：３０００ｐｐｍ、 Ｏ2：０．１５％、ＣＯ2：１０％、Ｈ2Ｏ：１０％、Ｎ2：残余、
Ａ／Ｆ＝１４．６、
空間速度：７２,０００／ｈ、
評価温度：１００〜５００℃、
昇温：１０℃／ｍｉｎ。
Model gas composition: CO: 0.3%, C 3 H 6 : 1000 ppm, NO: 3000 ppm, O 2 : 0.15%, CO 2 : 10%, H 2 O: 10%, N 2 : residual,
A / F = 14.6,
Space velocity: 72,000 / h,
Evaluation temperature: 100 to 500 ° C
Temperature increase: 10 ° C./min.
実施例１〜２及び比較例１〜３で調製したそれぞれの触媒を上記の条件下で９００℃で２４時間熱処理した後に触媒のコート層を掻き取り、得られた粉末についてＢＥＴ比表面積、ＯＳＣ性能及びＸＲＤ回折法によるＰｄの結晶子径を測定した。それらの結果は第２表に示す通りであった。 Each catalyst prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was heat-treated at 900 ° C. for 24 hours under the above conditions, and then the catalyst coating layer was scraped off. The resulting powder was subjected to BET specific surface area and OSC performance. And the crystallite diameter of Pd was measured by XRD diffraction method. The results were as shown in Table 2.
実施例１〜２及び比較例１〜２で調製したそれぞれの触媒についての第２表中のＢＥＴ比表面積及びＯＳＣ性能とキャリア中のＮｄ2Ｏ3の量（質量％）との相関関係は図１に示すグラフの通りである。図１に示すグラフから明らかなように、キャリア中のＮｄ2Ｏ3の量が２〜２０質量％である時に良好な結果が得られている。 The correlation between the BET specific surface area and OSC performance in Table 2 for each of the catalysts prepared in Examples 1 and 2 and Comparative Examples 1 and 2 and the amount (% by mass) of Nd 2 O 3 in the carrier is shown in FIG. As shown in the graph of FIG. As is clear from the graph shown in FIG. 1, good results are obtained when the amount of Nd 2 O 3 in the carrier is 2 to 20% by mass.
実施例１及び比較例１〜３で調製したそれぞれの触媒を上記の条件下で９００℃で２４時間熱処理した後にＸＲＤを求めたところ図２に示すチャートが得られた。図２に示すチャートから明らかなように、実施例１で調製した触媒については耐久後にも相分離がなく、熱安定性が改善されていた。比較例１で調製した触媒についてはＮｄ2Ｏ3を含有していないため耐久後に相分離し、熱安定性が悪かった。比較例２で調製した触媒についてはＮｄ2Ｏ3を過剰に（２４質量％）含有しているため耐久後に高角度側に相分離し、熱安定性が悪かった。比較例３で調製した触媒については耐久後にも相分離がなく、熱安定性が高かったが、ＰｄＯの金属化に起因するＰｄ微粒子の粒成長による触媒活性の低下が生じ、上記の第１表のデータから明らかなように触媒活性が低下していた。 Each catalyst prepared in Example 1 and Comparative Examples 1 to 3 was heat-treated at 900 ° C. for 24 hours under the above conditions, and then XRD was obtained. The chart shown in FIG. 2 was obtained. As apparent from the chart shown in FIG. 2, the catalyst prepared in Example 1 had no phase separation even after endurance, and the thermal stability was improved. Since the catalyst prepared in Comparative Example 1 did not contain Nd 2 O 3 , phase separation occurred after durability and the thermal stability was poor. Since the catalyst prepared in Comparative Example 2 contained Nd 2 O 3 in excess (24% by mass), it was phase-separated to the high angle side after durability, and the thermal stability was poor. The catalyst prepared in Comparative Example 3 had no phase separation even after endurance and high thermal stability. However, the catalyst activity decreased due to the growth of Pd fine particles due to the metallization of PdO. As apparent from the data, the catalytic activity was decreased.
Claims (7)
（２）ＺｒＯ2の量が５０〜９５質量％であり、ＣｅＯ2の量が０〜４０質量％であり、Ｎｄ2Ｏ3 の量が２〜２０質量％であり、Ｌａ2Ｏ3 の量が１〜１０質量％であるセリウム−ジルコニウム系複合酸化物からなるキャリアと、該キャリアに担持された
（２−１）金属Ｒｈ又はＲｈ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量との質量比が金属換算でＰｄ／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料、又は
（２−２）金属Ｒｈ又はＲｈ酸化物からなる触媒成分及び金属Ｐｔ又はＰｔ酸化物からなる触媒成分とを有し、Ｐｄの量とＲｈの量とＰｔの量との質量比が金属換算で（Ｐｔ＋Ｐｄ）／Ｒｈ＝１／１〜２０／１である内燃機関排気ガス浄化用触媒材料
とを含むことを特徴とする内燃機関排気ガス浄化用触媒材料。 (1) The amount of CeO 2 is 45 to 70% by mass, the amount of ZrO 2 is 20 to 45% by mass, the amount of Nd 2 O 3 is 2 to 20% by mass, and the amount of La 2 O 3 An internal combustion engine exhaust gas purification catalyst material comprising a carrier composed of a cerium-zirconium-based composite oxide having an amount of 1 to 10% by mass, and a catalyst component composed of metal Pd or Pd oxide supported on the carrier ;
(2) the amount of ZrO 2 is 50 to 95 wt%, the amount of CeO 2 is from 0 to 40 wt%, the amount of Nd 2 O 3 is 2-20 wt%, the amount of La 2 O 3 Having a carrier composed of a cerium-zirconium-based composite oxide having an amount of 1 to 10% by mass and a catalyst component composed of (2-1) metal Rh or Rh oxide supported on the carrier, An internal combustion engine exhaust gas purification catalyst material having a mass ratio with the amount of Rh in terms of metal of Pd / Rh = 1/1 to 20/1, or (2-2) a catalyst component comprising metal Rh or Rh oxide, and An internal combustion engine having a catalyst component made of metal Pt or a Pt oxide, and a mass ratio of the amount of Pd, the amount of Rh, and the amount of Pt being (Pt + Pd) / Rh = 1/1 to 20/1 in terms of metal Engine exhaust gas purification catalyst material for internal combustion engine exhaust gas purification Catalyst material.
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