JP6188185B2 - TiO2 composite porous silica photocatalyst particle production method and TiO2 composite porous silica photocatalyst particle - Google Patents
TiO2 composite porous silica photocatalyst particle production method and TiO2 composite porous silica photocatalyst particle Download PDFInfo
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Description
本発明は、メソポアとマイクロポアの細孔が共存し、ＣｕＫα線源を用いたＸ線回折パターンにおいて、回折角（２θ）５度以下に回折ピークが少なくとも１本認められるように前記メソポアが規則配列した多孔質シリカ粒子にＴｉＯ２ナノ粒子が担持され、光触媒活性を示すＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法及びＴｉＯ２複合化多孔質シリカ光触媒粒子に関する。 In the present invention, the mesopores are regularly arranged such that at least one diffraction peak is observed at a diffraction angle (2θ) of 5 degrees or less in an X-ray diffraction pattern using a CuKα radiation source in which pores of mesopores and micropores coexist. TiO 2 nanoparticles are supported on sequence porous silica particles, a method for manufacturing and TiO 2 composite porous silica photocatalyst particles of photocatalytic activity shown TiO 2 composite porous silica photocatalyst particles.
メソポアとマイクロポアの細孔が共存し、メソポアが規則配列した多孔質シリカ粒子が研究されている（例えば、特許文献１参照）。
この多孔質シリカ粒子は、除去対象となる物質を細孔内に動的に吸着させる動的吸着能が大きく、揮発性有機化合物（ＶＯＣ）等の吸着剤として極めて有用である。
Research has been conducted on porous silica particles in which mesopores and micropores coexist and mesopores are regularly arranged (see, for example, Patent Document 1).
The porous silica particles have a large dynamic adsorption capacity for dynamically adsorbing a substance to be removed in the pores, and are extremely useful as an adsorbent such as a volatile organic compound (VOC).
近年では、こうした多孔質シリカ粒子の特性を利用して、分解対象となる有機分子を細孔内に吸着させ、ＴｉＯ２の光触媒作用により高い光触媒活性を示す光触媒体が提案されている（特許文献２）。
この光触媒体は、可視光応答型光触媒酸化チタンと多孔質シリカの複合体として形成され、その製造方法としては、溶媒に酸化チタン粒子を分散させるとともに細孔形成剤を溶解させた後、加水分解性シリコン化合物を加水分解することにより得られた固形物を焼成することとされる。
細孔形成剤としては、規則的な細孔を得るため、ポリエチレン−ポリプロピロピレン−ポリエチレンのトリブロック共重合体が好適に用いられ、このトリブロック共重合体を用いた光触媒体の具体的な製造方法としては、例えば、次のように開示される（特許文献２の実施例１参照）。
水にトリブロック共重合体を溶解させ、塩酸水溶液を添加した後、更に酸化チタンを添加して、室温で３時間撹拌する。次いで、珪酸エチルを添加し、室温で１８時間攪拌した後、４０℃で１０時間加熱し、引き続き８０℃で３０時間加熱する。その後、生じた固形物を濾過、水洗した後、室温にて乾燥し、空気中で５００℃にて６時間焼成して有機物を除去し、光触媒体を得る。
しかしながら、この製造方法では、酸化チタン粒子を溶液系に直接添加するため、均一な分散系の形成に時間を要し（３時間攪拌）、結果的に反応時間に長時間を要する問題がある。
また、均一な分散系の形成に続くメソ構造体（固形物）の形成では、低温であるほど多くの時間を要し、メソ構造体の形成を促進しつつ、全体の反応時間をできる限り短縮化するためには、生成した生成物を比較的高い温度で長時間熟成することが必要となる（１８時間攪拌して生成物を生成後、４０℃で１０時間、８０℃で３０時間熟成）。
このような反応の反応時間をより短縮化させ、より低温条件で効率的に行うためには、シリカ源として珪酸エチルよりも水ガラスが好適であり、前記トリブロック共重合体と水ガラスを用いることを前提とした反応系の構築が必要である。
In recent years, a photocatalyst having a high photocatalytic activity due to the photocatalytic action of TiO 2 has been proposed in which organic molecules to be decomposed are adsorbed in pores by utilizing the characteristics of such porous silica particles (Patent Literature). 2).
This photocatalyst is formed as a composite of visible light responsive photocatalytic titanium oxide and porous silica. The production method includes dispersing titanium oxide particles in a solvent and dissolving a pore-forming agent, followed by hydrolysis. The solid material obtained by hydrolyzing the functional silicon compound is calcined.
In order to obtain regular pores, a polyethylene-polypropylene-polyethylene triblock copolymer is preferably used as the pore-forming agent, and a specific production of a photocatalyst using the triblock copolymer is preferred. As a method, for example, it is disclosed as follows (see Example 1 of Patent Document 2).
The triblock copolymer is dissolved in water, an aqueous hydrochloric acid solution is added, titanium oxide is further added, and the mixture is stirred at room temperature for 3 hours. Next, ethyl silicate is added and stirred at room temperature for 18 hours, followed by heating at 40 ° C. for 10 hours, followed by heating at 80 ° C. for 30 hours. Thereafter, the resulting solid matter is filtered, washed with water, dried at room temperature, and calcined in air at 500 ° C. for 6 hours to remove organic matter, thereby obtaining a photocatalyst.
However, in this production method, since titanium oxide particles are directly added to the solution system, it takes time to form a uniform dispersion (3 hours stirring), resulting in a problem that a long reaction time is required.
Also, the formation of mesostructures (solids) following the formation of a uniform dispersion requires more time at lower temperatures, and the overall reaction time is reduced as much as possible while promoting the formation of mesostructures. In order to achieve this, it is necessary to age the produced product at a relatively high temperature for a long time (after producing the product by stirring for 18 hours, aging at 40 ° C. for 10 hours and 80 ° C. for 30 hours) .
In order to further shorten the reaction time of such a reaction and perform it efficiently at a lower temperature, water glass is more preferable than ethyl silicate as the silica source, and the triblock copolymer and water glass are used. It is necessary to construct a reaction system based on this assumption.
本発明は、従来における前記諸問題を解決し、以下の目的を達成することを課題とする。即ち、本発明は、メソポアとマイクロポアの細孔が共存し、メソポアが規則配列した多孔質シリカ粒子の細孔外表面にＴｉＯ２ナノ粒子が担持され、光触媒活性を示すＴｉＯ２複合化多孔質シリカ光触媒粒子を短時間かつ低温の生成条件で効率良く製造可能なＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法及び該ＴｉＯ２複合化多孔質シリカ光触媒粒子を提供することを目的とする。 An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is a TiO 2 composite porous material in which pores of mesopores and micropores coexist, TiO 2 nanoparticles are supported on the outer surface of the pores of porous silica particles in which mesopores are regularly arranged, and exhibit photocatalytic activity. It is an object of the present invention to provide a method for producing TiO 2 composite porous silica photocatalyst particles capable of efficiently producing silica photocatalyst particles in a short time and under low temperature production conditions, and the TiO 2 composite porous silica photocatalyst particles.
前記課題を解決するために、本発明者らは、先ず、均一な分散系の形成時間を短縮するために、溶液系にＴｉＯ２を直接添加することに代えて、予め光触媒活性を示すＴｉＯ２ナノ粒子を溶媒に均一に分散させてゾル化させたＴｉＯ２ゾルを添加することを検討した。
細孔形成剤には、トリブロック共重合体を用い、シリカ源には、水ガラスを用い、反応系の溶液には、鉱酸水溶液用いて酸性条件とし、反応系を構築した。
また、ＴｉＯ２ゾルの分散剤としては、有機及び無機化合物が使用されている。無機化合物の分散剤は、製造現場での揮発性有機化合物（ＶＯＣ）処理装置の使用が不要であるなどコストの面で有利であり、本願では規則的配列構造を有するＴｉＯ２複合化多孔質シリカ光触媒粒子製造の効率化を目指し、まず硝酸中に分散された市販ＴｉＯ２ゾルの使用を検討した。
しかしながら、無機化合物の分散剤を用いるＴｉＯ２ゾルを前記反応系で反応させたところ、予想に反し、多孔質シリカとＴｉＯ２ナノ粒子とが分離して複合化することができないことが確認された。
一方、ＴｉＯ２ナノ粒子の溶液中での凝集を防ぐ有機分散剤を含む有機溶媒にＴｉＯ２ナノ粒子を投入したＴｉＯ２ゾル溶液を前記反応系で反応させたところ、多孔質シリカとＴｉＯ２ナノ粒子とを複合化することができ、好適な細孔の規則的配列構造を有するＴｉＯ２複合化多孔質シリカ光触媒粒子を短時間、かつ、低温で効率良く製造することができることの知見を得た。
In order to solve the above-mentioned problems, the present inventors firstly replaced TiO 2 directly with a solution system in order to shorten the formation time of a uniform dispersion, but previously exhibited TiO 2 exhibiting photocatalytic activity. The addition of a TiO 2 sol in which nanoparticles were dispersed in a solvent and made into a sol was studied.
A triblock copolymer was used as the pore-forming agent, water glass was used as the silica source, and a mineral acid aqueous solution was used as the reaction system solution under acidic conditions to construct a reaction system.
In addition, organic and inorganic compounds are used as dispersants for the TiO 2 sol. The inorganic compound dispersant is advantageous in terms of cost because it does not require the use of a volatile organic compound (VOC) treatment apparatus at the production site. In this application, the TiO 2 composite porous silica having a regular array structure is used. With the aim of increasing the efficiency of photocatalyst particle production, the use of a commercially available TiO 2 sol dispersed in nitric acid was first examined.
However, when a TiO 2 sol using an inorganic compound dispersant was reacted in the reaction system, it was confirmed that the porous silica and the TiO 2 nanoparticles could not be separated and combined, contrary to expectations. .
Meanwhile, on reaction of TiO 2 sol solution was charged TiO 2 nanoparticles in an organic solvent containing an organic dispersing agent to prevent aggregation in solution of TiO 2 nanoparticles in the reaction system, porous silica and TiO 2 nano TiO 2 composite porous silica photocatalyst particles that can be composited with particles and have a suitable regular pore structure can be efficiently produced in a short time at a low temperature. .
前記課題を解決するための手段としては、以下の通りである。即ち、
＜１＞ メソポアとマイクロポアの細孔が共存し、ＣｕＫα線源を用いたＸ線回折パターンにおいて、回折角（２θ）５度以下に回折ピークが少なくとも１本認められるように前記メソポアが規則配列した多孔質シリカ粒子の細孔外表面にＴｉＯ２ナノ粒子が担持され、光触媒活性を示すＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法であって、細孔形成剤としてポリプロピレンオキシドの重量平均分子量が２，５００以上で、ポリエチレンオキシドの重合割合が４０％以上のポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）であるトリブロック共重合体を硝酸水溶液に添加して溶解させ、前記トリブロック共重合体を含む第１の酸性溶液を調製するトリブロック共重合体含有酸性溶液調製工程と、前記ＴｉＯ２ナノ粒子がアセチルアセトンにより炭素数１〜４の低級アルコール中に分散されたＴｉＯ２ゾルを前記第１の酸性溶液に添加し、前記ＴｉＯ２ナノ粒子及び前記トリブロック共重合体を含有する第２の酸性溶液を調製するＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程と、前記第２の酸性溶液とシリカ源としての水ガラス水溶液とを混合し、水ガラス混合液を調製する水ガラス混合工程と、前記水ガラス混合液を２５℃〜４０℃の温度条件下で１時間〜６時間撹拌し、シリカ母材の外壁に前記トリブロック共重合体が規則配列された粒子の表面に前記ＴｉＯ２ナノ粒子が担持された１次粒子が凝集した２次粒子の前駆体粒子を形成する前駆体粒子形成工程と、前記水ガラス混合液から分離された前記前駆体粒子を４００℃〜１，０００℃の温度条件下で０．５時間〜６時間焼成して前記前駆体粒子から前記トリブロック共重合体を除去し、前記ＴｉＯ２複合化多孔質シリカ光触媒粒子を形成する光触媒粒子形成工程と、を含むことを特徴とするＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法。
＜２＞ ＴｉＯ２複合化多孔質シリカ光触媒粒子がＴｉＯ２ナノ粒子を１質量％〜４０質量％含む前記＜１＞に記載のＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法。
＜３＞ 光触媒粒子形成工程が、前駆体粒子を４００℃〜８００℃の温度条件下で０．５時間〜４時間焼成する工程である前記＜１＞から＜２＞のいずれかに記載のＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法。
Means for solving the problems are as follows. That is,
<1> Mesopores and micropores coexist, and the mesopores are regularly arranged so that at least one diffraction peak is observed at a diffraction angle (2θ) of 5 degrees or less in an X-ray diffraction pattern using a CuKα radiation source. A method for producing TiO 2 composite porous silica photocatalyst particles having TiO 2 nanoparticles supported on the outer surface of the pores of the prepared porous silica particles and exhibiting photocatalytic activity, wherein the weight average molecular weight of polypropylene oxide as a pore forming agent Is a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) having a polymerization rate of polyethylene oxide of 2,500 or more and a polymerization rate of polyethylene oxide of 40% or more , Triblock copolymer-containing acidic solution for preparing a first acidic solution containing a triblock copolymer Preparation process, the TiO 2 nanoparticles was added TiO 2 sol dispersed in a lower alcohol of 1-4 carbon atoms by acetylacetone in the first acidic solution, the TiO 2 nanoparticles and the triblock A TiO 2 -triblock copolymer-containing acidic solution preparation step for preparing a second acidic solution containing a polymer, the second acidic solution and a water glass aqueous solution as a silica source are mixed, and water glass mixing is performed. A water glass mixing step for preparing a liquid and the water glass mixed liquid are stirred for 1 hour to 6 hours under a temperature condition of 25 ° C. to 40 ° C., and the triblock copolymer is regularly arranged on the outer wall of the silica base material. A precursor particle forming step of forming precursor particles of secondary particles in which the primary particles having the TiO 2 nanoparticles supported on the surface of the particles are aggregated, and the previous separated from the water glass mixture The precursor particles are calcined at a temperature of 400 ° C. to 1,000 ° C. for 0.5 hours to 6 hours to remove the triblock copolymer from the precursor particles, and the TiO 2 composite porous silica photocatalyst A method for producing TiO 2 composite porous silica photocatalyst particles, comprising: a photocatalyst particle forming step of forming particles .
<2> method for producing a TiO 2 composite porous silica photocatalyst particles according to the TiO 2 composite porous silica photocatalyst particles containing TiO 2 nanoparticles 1 wt% to 40 wt% <1>.
< 3 > The TiO according to any one of <1> to < 2 >, wherein the photocatalyst particle forming step is a step of firing the precursor particles at a temperature of 400 ° C to 800 ° C for 0.5 hours to 4 hours. 2. A method for producing composite porous silica photocatalyst particles.
本発明によれば、従来技術における前記諸問題を解決することができ、メソポアとマイクロポアの細孔が共存し、メソポアが規則配列した多孔質シリカ粒子の細孔外表面にＴｉＯ２ナノ粒子が担持され、光触媒活性を示すＴｉＯ２複合化多孔質シリカ光触媒粒子を短時間かつ低温の生成条件で効率良く製造可能なＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法及び該ＴｉＯ２複合化多孔質シリカ光触媒粒子を提供することができる。 According to the present invention, the above-mentioned problems in the prior art can be solved, and the pores of mesopores and micropores coexist, and TiO 2 nanoparticles are formed on the outer surface of the porous silica particles in which mesopores are regularly arranged. supported, manufacturing method and the TiO 2 composite porous TiO 2 composite porous silica optical efficiency of the catalyst particles short time and at low temperature producing conditions well manufacturable TiO 2 composite porous silica photocatalyst particles showing a photocatalytic activity Silica photocatalytic particles can be provided.
（ＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法）
本発明のＴｉＯ２複合化多孔質シリカ光触媒粒子（以下、単に「光触媒粒子」と称することがある）の製造方法は、メソポアとマイクロポアの細孔が共存し、ＣｕＫα線源を用いたＸ線回折パターンにおいて、回折角（２θ）５度以下に回折ピークが少なくとも１本認められるように前記メソポアが規則配列した多孔質シリカ粒子の細孔外表面にＴｉＯ２ナノ粒子が担持され、光触媒活性を示すＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法であって、トリブロック共重合体含有酸性溶液調製工程と、ＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程と、水ガラス混合工程と、前駆体粒子形成工程と、光触媒粒子形成工程とを含み、必要に応じてその他の工程を含む。
(Method for producing TiO 2 composite porous silica photocatalyst particles)
The method for producing TiO 2 composite porous silica photocatalyst particles (hereinafter sometimes simply referred to as “photocatalyst particles”) according to the present invention comprises X-rays using a CuKα radiation source in which pores of mesopores and micropores coexist. In the diffraction pattern, TiO 2 nanoparticles are supported on the outer surface of the pores of the porous silica particles in which the mesopores are regularly arranged so that at least one diffraction peak is observed at a diffraction angle (2θ) of 5 degrees or less. A method for producing TiO 2 composite porous silica photocatalyst particles shown in which a triblock copolymer-containing acidic solution preparation step, a TiO 2 -triblock copolymer-containing acidic solution preparation step, a water glass mixing step, It includes a precursor particle forming step and a photocatalyst particle forming step, and includes other steps as necessary.
＜トリブロック共重合体含有酸性溶液調製工程＞
前記トリブロック共重合体含有酸性溶液調製工程は、細孔形成剤としてポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）及びポリエチレンオキシド−ポリブチレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＢＯ−ＰＥＯ）のいずれかのトリブロック共重合体を強酸性の鉱酸水溶液に添加して溶解させ、前記トリブロック共重合体を含む第１の酸性溶液を調製する工程である。
<Triblock copolymer-containing acidic solution preparation step>
The triblock copolymer-containing acidic solution preparation step includes polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) and polyethylene oxide-polybutylene oxide-polyethylene oxide (PEO-PBO-PEO) as pore forming agents. The triblock copolymer is added to a strongly acidic mineral acid aqueous solution and dissolved to prepare a first acidic solution containing the triblock copolymer.
前記トリブロック共重合体としては、前記ポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）及び前記ポリエチレンオキシド−ポリブチレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＢＯ−ＰＥＯ）のいずれかから選択することができるが、前記ポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）が好ましく、中でも、ポリプロピレンオキシドの重量平均分子量が２，５００以上で、ポリエチレンオキシドの重合割合が４０％以上のポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）が特に好ましい。
前記ポリエチレンオキシドの重合割合が４０％未満であると、疎水性が強く、生成される前記光触媒粒子の細孔配列の１次元チャンネルがハニカム状に配列し易く、外界の分子、イオン等との接触効率が低下し、３次元細孔構造に比べ分解・除去の対象となる分子等の吸着能が低下することがある。なお、前記重合割合の上限としては、８０％である。
また、ポリプロピレンオキシドの重量平均分子量が２，５００未満であると、ポリエチレンオキシド量に係わらず前記光触媒粒子のメソポアの孔径が小さくなり、さらに親水的であるほど、全細孔容積におけるマイクロポアの割合が高くなり、更には、メソポアの存在が認められなくなり、前記吸着能は向上するものの、一旦吸着した前記分子等の脱離が困難となることがある。なお、前記重量平均分子量の上限としては、４，０００である。
前記トリブロック共重合体としては、特に制限はなく、市販のものを用いることができ、例えば、前記ポリプロピレンオキシドの重量平均分子量が２，５００以上で、ポリエチレンオキシドの重合割合が４０％以上のポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）としては、ＢＡＳＦ社製商品ＰｌｕｒｏｎｉｃのＰ１０４、Ｐ１０５、Ｆ１２７、Ｆ１０８などを用いることができる。中でも、フレーク状で秤量しやすく、酸への溶解性も優れ、比較的広い反応条件下でメソポアを形成し易いＦ１２７が特に好ましい。
また、前記トリブロック共重合体の添加量としては、特に制限はないが、シリカ源に用いられる水ガラス中のＳｉに対し、トリブロック共重合体／ＳｉＯ２のモル比で、０．００３〜０．０２が好ましい。
The triblock copolymer is selected from the polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) and the polyethylene oxide-polybutylene oxide-polyethylene oxide (PEO-PBO-PEO). However, polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) is preferable, and in particular, polyethylene oxide having a weight average molecular weight of 2,500 or more and a polymerization ratio of polyethylene oxide of 40% or more. Polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) is particularly preferred.
When the polymerization ratio of the polyethylene oxide is less than 40%, the hydrophobicity is strong, and the one-dimensional channels of the pore arrangement of the generated photocatalyst particles are easily arranged in a honeycomb shape, and contact with molecules, ions, etc. in the outside world The efficiency is lowered, and the adsorption ability of molecules or the like to be decomposed / removed may be reduced as compared with the three-dimensional pore structure. The upper limit of the polymerization rate is 80%.
In addition, when the weight average molecular weight of polypropylene oxide is less than 2,500, the pore diameter of the mesopores of the photocatalyst particles is small regardless of the amount of polyethylene oxide, and the more hydrophilic the proportion of micropores in the total pore volume. In addition, although the presence of mesopores is not recognized and the adsorption ability is improved, it may be difficult to desorb the molecules once adsorbed. The upper limit of the weight average molecular weight is 4,000.
The triblock copolymer is not particularly limited, and a commercially available product can be used. For example, a polymer having a weight average molecular weight of 2,500 or more and a polymerization rate of polyethylene oxide of 40% or more is used. As ethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO), PSF, P105, F127, F108, etc. manufactured by BASF Corporation, Pluronic, can be used. Among these, F127 is particularly preferable because it is flaky and easy to weigh, has excellent solubility in acids, and easily forms mesopores under relatively wide reaction conditions.
In addition, the amount of the triblock copolymer added is not particularly limited, but is 0.003 to a molar ratio of triblock copolymer / SiO 2 with respect to Si in water glass used as a silica source. 0.02 is preferred.
前記鉱酸水溶液としては、特に制限はなく目的に応じて適宜選択することができ、塩酸水溶液、硝酸水溶液等を用いることができるが、１次粒子のナノ構造を破壊することなく、２次粒子の成長を最も促進し、短時間で目的の光触媒粒子を得られるという効率的な合成上の観点から、硝酸水溶液が好ましい。 There is no restriction | limiting in particular as said mineral acid aqueous solution, According to the objective, it can select suitably, Hydrochloric acid aqueous solution, nitric acid aqueous solution etc. can be used, However, Secondary particle | grains are destroyed, without destroying the nanostructure of a primary particle. From the viewpoint of efficient synthesis that the target photocatalyst particles can be obtained in a short time, an aqueous nitric acid solution is preferable.
＜ＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程＞
前記ＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程は、ＴｉＯ２ナノ粒子が有機分散剤により有機溶媒中に分散されたＴｉＯ２ゾルを前記第１の酸性溶液に添加し、前記ＴｉＯ２ナノ粒子及び前記トリブロック共重合体を含有する第２の酸性溶液を調製する工程である。
<TiO 2 - triblock copolymer containing acidic solution preparation step>
The TiO 2 - triblock copolymer containing acidic solution preparation step, was added TiO 2 sol TiO 2 nanoparticles dispersed in an organic solvent by an organic dispersant to said first acidic solution, the TiO 2 nano This is a step of preparing a second acidic solution containing particles and the triblock copolymer.
前記ＴｉＯ２ナノ粒子としては、光触媒活性を有する限り特に制限はなく、目的に応じて適宜選択することができるが、アナターゼの結晶構造、アナターゼとルチルの混合相からなる結晶構造を有するものが好ましい。
また、前記ＴｉＯ２ナノ粒子の平均粒子径としては、特に制限はないが、５ｎｍ〜３０ｎｍが好ましい。
また、前記ＴｉＯ２ゾル中の前記ＴｉＯ２ナノ粒子の添加量としては、特に制限はないが、前記シリカ源に用いられる水ガラス中のＳｉに対し、ＴｉＯ２ナノ粒子／ＳｉＯ２のモル比で、０．００７５〜０．５が好ましく、０．０１５〜０．３３がより好ましく、０．０２３〜０．２５が特に好ましい。この前記ＴｉＯ２ゾルに添加される前記ＴｉＯ２ナノ粒子は、ほぼ全量が前記光触媒粒子中に固定される。前記光触媒粒子中の前記ＴｉＯ２ナノ粒子の含有率としては、１質量％〜４０質量％が好ましく、２質量％〜３０質量％がより好ましく、３質量％〜２５質量％が特に好ましい。前記含有率が１質量％未満であると、ＴｉＯ２量が過少であり十分な光触媒活性が発揮されないことがあり、４０質量％を超えると、ＴｉＯ２ナノ粒子間の接触面積が大きくなり、加熱によって粒成長したり、細孔径の縮小が顕著になるため複合化に見合う光触媒能が認められなくなることがある。
また、前記ＴｉＯ２ナノ粒子としては、特に制限はなく、市販のものを用いることができ、例えば、石原産業社製のＳＴ−０１を用いることができる。
The TiO 2 nanoparticles are not particularly limited as long as they have photocatalytic activity, and can be appropriately selected according to the purpose, but those having a crystal structure of anatase and a mixed phase of anatase and rutile are preferable. .
Further, as the average particle diameter of the TiO 2 nanoparticles it is not particularly limited, 5 nm to 30 nm is preferable.
Further, as the amount of the TiO 2 nanoparticles TiO 2 sol, in particular, without limitation, with respect to Si of the water in the glass used for the silica source, at a molar ratio of TiO 2 nanoparticles / SiO 2 0.0075 to 0.5 is preferable, 0.015 to 0.33 is more preferable, and 0.023 to 0.25 is particularly preferable. Almost all of the TiO 2 nanoparticles added to the TiO 2 sol are fixed in the photocatalyst particles. The content of the TiO 2 nanoparticles in the photocatalyst particles is preferably 1% by mass to 40% by mass, more preferably 2% by mass to 30% by mass, and particularly preferably 3% by mass to 25% by mass. When the content is less than 1% by mass, the amount of TiO 2 is too small and sufficient photocatalytic activity may not be exhibited. When the content exceeds 40% by mass, the contact area between the TiO 2 nanoparticles increases and heating is performed. As a result, the photocatalytic ability commensurate with the composition may not be recognized due to grain growth and significant reduction in pore diameter.
Further, as the TiO 2 nanoparticles is not particularly limited and may be those commercially available, for example, can be used ST-01 Ishihara Sangyo Kaisha Ltd..
前記ＴｉＯ２ナノ粒子と前記多孔質シリカとが分離等せず、複合化できることを目的として、前記ＴｉＯ２ゾルの溶媒には、有機溶媒が用いられる。前記ＴｉＯ２ゾルは、ＴｉＯ２ナノ粒子の表面に吸着してＴｉＯ２ナノ粒子の凝集を抑制する分散剤が溶解した溶媒を使用することで得られるが、これら分散剤は有機化合物からなるため、ＴｉＯ２ゾルの溶媒としては前記有機溶媒を用いる。
前記有機溶媒としては、特に制限はなく、目的に応じて適宜選択することができるが、エタノール、イソプロパノール、ブタノール等の炭素数１〜１０の低級アルコールが使い易い。なお、前記低級アルコールの炭素鎖としては、直鎖であっても分岐していてもよい。
An organic solvent is used as the solvent of the TiO 2 sol for the purpose of allowing the TiO 2 nanoparticles and the porous silica to be combined without being separated. Since the TiO 2 sol is obtained by using a solvent dispersing agent inhibits aggregation of TiO 2 nanoparticles adsorbed on the surface of the TiO 2 nanoparticles was dissolved, consisting dispersants organic compounds, The organic solvent is used as a solvent for the TiO 2 sol.
There is no restriction | limiting in particular as said organic solvent, Although it can select suitably according to the objective, C1-C10 lower alcohols, such as ethanol, isopropanol, butanol, are easy to use. The carbon chain of the lower alcohol may be linear or branched.
前記有機分散剤は、分散したＴｉＯ２粒子の再凝集を抑制する役割で用いられる。前記有機分散剤としては、特に制限はなく、目的に応じて適宜選択することができ、ジエタノールアミン、トリエタノールアミンなどの低級アミン類、ジエチレングリコールモノエチルエーテルなどの低級エーテル類、アセチルアセトン等のケトン類が挙げられる。但し、これらの中では、吸着力の強いアセチルアセトンが使い易い。 The organic dispersant is used for suppressing reaggregation of dispersed TiO 2 particles. The organic dispersant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include lower amines such as diethanolamine and triethanolamine, lower ethers such as diethylene glycol monoethyl ether, and ketones such as acetylacetone. Can be mentioned. However, among these, acetylacetone having a strong adsorption power is easy to use.
前記ＴｉＯ２ゾルとしては、特に制限はないが、水を添加して調製されていてもよい。
前記水は、ゾル溶液を添加する反応溶液が水溶液であることから、混合による相分離の発生を抑制する役割で用いられる。前記水としては、純水等の特定の処理が施された水であってもよく、施されていない水であってもよいが、純水等の特定の処理が施された水が好ましい。
The TiO 2 sol is not particularly limited, but may be prepared by adding water.
Since the reaction solution to which the sol solution is added is an aqueous solution, the water is used for suppressing the occurrence of phase separation due to mixing. The water may be water that has been subjected to a specific treatment such as pure water, or may be water that has not been subjected to water, but water that has been subjected to a specific treatment such as pure water is preferred.
前記ＴｉＯ２ナノ粒子のゾル化方法としては、特に制限はなく、例えば、通常の攪拌操作、超音波分散あるいは乳化機等による機械的操作が挙げられる。
なお、前記ＴｉＯ２ゾルとしては、市販のものを用いることができ、例えば、富士化学社製のものを用いることができる。
As a sol method of the TiO 2 nanoparticles are not particularly limited, for example, ordinary stirring operation, mechanical manipulation by ultrasonic dispersing or emulsifier, and the like.
Incidentally, as the TiO 2 sol may be used a commercially available, for example, can be used those manufactured by Fuji Chemical Company.
＜水ガラス混合工程＞
水ガラス混合工程は、前記第２の酸性溶液とシリカ源としての水ガラス水溶液とを混合し、水ガラス混合液を調製する水ガラス混合工程である。
<Water glass mixing process>
The water glass mixing step is a water glass mixing step in which the second acidic solution and a water glass aqueous solution as a silica source are mixed to prepare a water glass mixed solution.
前記水ガラス水溶液としては、水ガラスに水を添加して調製される。前記水ガラスとしては、特に制限はなく、公知の水ガラスから目的に応じて適宜選択することができ、例えば、ＪＩＳ３号水ガラス（ＳｉＯ２：２９．１質量％、Ｎａ２Ｏ：９．５質量％、Ｈ２Ｏ：６１．４質量％）などを用いることができる。 The water glass aqueous solution is prepared by adding water to water glass. Examples of the water glass is not particularly limited and may be suitably selected from known water glass, for example, JIS three water glass (SiO 2: 29.1 wt%, Na 2 O: 9.5 Mass%, H 2 O: 61.4 mass%) and the like can be used.
＜前駆体粒子形成工程＞
前記前駆体粒子形成工程は、前記水ガラス混合液を２５℃〜４０℃の温度条件下で１時間〜６時間撹拌し、シリカ母材の外壁に前記トリブロック共重合体が規則配列された粒子の表面に前記ＴｉＯ２ナノ粒子が担持された１次粒子が凝集した２次粒子の前駆体粒子を形成する工程である。
<Precursor particle formation step>
In the precursor particle forming step, the water glass mixed liquid is stirred for 1 hour to 6 hours under a temperature condition of 25 ° C. to 40 ° C., and the triblock copolymer is regularly arranged on the outer wall of the silica base material. This is a step of forming precursor particles of secondary particles in which the primary particles carrying the TiO 2 nanoparticles are agglomerated on the surface.
前記水ガラス混合液を２５℃〜４０℃の温度条件下で１時間〜６時間撹拌させた際に生ずる反応の反応機構について説明する。
強酸性条件下では、Ｓｉ溶存種は、プラス電荷を帯び（Ｉ＋）、また、前記トリブロック共重合体（非イオン性界面活性剤、［Ｎ０］）も、親水基部分（ＥＯ）がプロトン［Ｈ＋］との相互作用によってプラスに帯電し、両表面間にＮＯ３ −等の陰イオン［Ｘ−］が介在することで、電気的に安定なメソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］を形成すると推定される。この前駆体は、シリカ成分と前記トリブロック共重合体のミセルからなる無機有機ナノ複合体であり、一般的にメソポーラス構造、即ち、細孔構造は、溶液組成、反応温度、前記トリブロック共重合体の新疎水性の程度、及び陰イオンの種類等、様々な反応条件に基づく影響を大きく受ける。前記トリブロック共重合体の疎水性が高い場合、図１（ａ）に示す六方晶系の前記前駆体を形成し易く、親水性が高い場合、図１（ｂ）に示す立方晶系の前記メソポーラス構造前駆体が形成される傾向がある。なお、前記メソポーラス構造前駆体は、前記光触媒粒子の前駆体の１次粒子に相当するものであり、実際の生成物として得られるのは、図１（ｃ）及び図１（ｄ）に示すように１次粒子の集合体である２次粒子である。なお、図１（ａ）は、六方晶規則構造を有する１次粒子を示す説明図であり、図１（ｂ）は、立方晶規則構造を有する１次粒子を示す説明図であり、図１（ｃ）は、六方晶規則構造を有する２次粒子を示す説明図であり、図１（ｄ）は、立方晶規則構造を有する２次粒子を示す説明図である。なお、図１（ａ）〜（ｄ）では、煩雑になるため個々のＳｉＯ２成分を描画していないが、上記の通りＥＯ部と緩く結合して、棒状ミセルの側面を取り囲むように存在している。また、図１（ｃ），（ｄ）中の「○」印は、ＴｉＯ２ナノ粒子を表している。
The reaction mechanism of the reaction that occurs when the water glass mixture is stirred for 1 hour to 6 hours under a temperature condition of 25 ° C. to 40 ° C. will be described.
Under strongly acidic conditions, the Si-dissolved species is positively charged (I + ), and the triblock copolymer (nonionic surfactant, [N 0 ]) also has a hydrophilic group (EO). By being positively charged by interaction with proton [H + ] and an anion [X − ] such as NO 3 − being interposed between both surfaces, an electrically stable mesoporous structure precursor [N 0 H + ] [X − I + ]. This precursor is an inorganic organic nanocomposite composed of a silica component and a micelle of the triblock copolymer, and generally has a mesoporous structure, that is, a pore structure, a solution composition, a reaction temperature, the triblock copolymer. It is greatly influenced by various reaction conditions such as the degree of new hydrophobicity of the coalescence and the type of anion. When the triblock copolymer is highly hydrophobic, the hexagonal precursor shown in FIG. 1 (a) is easily formed, and when the hydrophilicity is high, the cubic crystal shown in FIG. 1 (b) is formed. There is a tendency for mesoporous structure precursors to be formed. The mesoporous structure precursor corresponds to the primary particles of the photocatalyst particle precursor, and the actual product is obtained as shown in FIGS. 1 (c) and 1 (d). And secondary particles that are aggregates of primary particles. 1A is an explanatory diagram showing primary particles having a hexagonal regular structure, and FIG. 1B is an explanatory diagram showing primary particles having a cubic regular structure. (C) is explanatory drawing which shows the secondary particle which has a hexagonal ordered structure, FIG.1 (d) is explanatory drawing which shows the secondary particle which has a cubic ordered structure. In FIGS. 1A to 1D, individual SiO 2 components are not drawn for the sake of complexity, but they are loosely coupled with the EO portion as described above and surround the side surfaces of the rod-like micelles. ing. In addition, “◯” marks in FIGS. 1C and 1D represent TiO 2 nanoparticles.
前記ＴｉＯ２ナノ粒子は、一般的に酸性条件下で粒子表面がプラスに帯電するが、前記有機分散剤により前記有機溶媒に分散された前記ＴｉＯ２ナノ粒子のゾルを用いる本発明の条件では、一般的な表面状態とは異なる表面状態を有するものと推定され、メソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］との複合化が可能とされる。
一方、無機化合物の分散剤を用いる条件では、メソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］と［ＴｉＯ２］の相互作用がなく、プラスに帯電した［ＴｉＯ２］の反発力により前記ＴｉＯ２ナノ粒子が前記１次粒子、前記２次粒子中に固定されない。
結果的に、有機系ゾルの場合には、［ＴｉＯ２］とメソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］との間に引き合う相互作用が存在するものと推察される。
The TiO 2 nanoparticles generally have a positively charged particle surface under acidic conditions, but under the conditions of the present invention using a sol of the TiO 2 nanoparticles dispersed in the organic solvent by the organic dispersant, It is presumed to have a surface state different from the general surface state, and can be combined with the mesoporous structure precursor [N 0 H + ] [X − I + ].
On the other hand, under the conditions using an inorganic compound dispersant, there is no interaction between the mesoporous structure precursors [N 0 H + ] [X − I + ] and [TiO 2 ], and the repulsive force of the positively charged [TiO 2 ] Therefore, the TiO 2 nanoparticles are not fixed in the primary particles and the secondary particles.
As a result, in the case of an organic sol, it is presumed that there is an attractive interaction between [TiO 2 ] and the mesoporous structure precursor [N 0 H + ] [X − I + ].
＜光触媒粒子形成工程＞
前記光触媒粒子形成工程は、前記水ガラス混合液から分離された前記前駆体粒子を４００℃〜１，０００℃の温度条件下で０．５時間〜６時間焼成して前記前駆体粒子から前記トリブロック共重合体を除去し、前記ＴｉＯ２複合化多孔質シリカ光触媒粒子を形成する工程である。前記焼成としては、特に制限はないが、４００℃〜８００℃の温度条件下で０．５時間〜４時間焼成する条件で行うことが好ましい。
<Photocatalyst particle formation process>
In the photocatalyst particle forming step, the precursor particles separated from the water glass mixture are calcined at a temperature of 400 ° C. to 1,000 ° C. for 0.5 hours to 6 hours, and then the precursor particles are converted from the precursor particles. In this step, the block copolymer is removed to form the TiO 2 composite porous silica photocatalyst particles. Although there is no restriction | limiting in particular as said baking, It is preferable to carry out on the conditions baked on the temperature conditions of 400 to 800 degreeC for 0.5 to 4 hours.
前記水ガラス混合液から前記前駆体粒子を分離する方法としては、特に制限はなく、濾別する方法が挙げられる。なお、濾別後は、水洗し乾燥させることが好ましい。 There is no restriction | limiting in particular as a method of isolate | separating the said precursor particle | grain from the said water glass liquid mixture, The method of separating by filtration is mentioned. In addition, it is preferable to wash with water and dry after filtration separation.
＜その他の工程＞
前記その他の工程としては、本発明の効果を損なわない限り特に制限はなく、目的に応じて適宜選択することができる。
<Other processes>
The other steps are not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected depending on the purpose.
（ＴｉＯ２複合化多孔質シリカ光触媒粒子）
本発明のＴｉＯ２複合化多孔質シリカ光触媒粒子は、本発明の前記ＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法により製造されることを特徴とする。
(TiO 2 composite porous silica photocatalyst particles)
TiO 2 composite porous silica photocatalyst particles of the present invention is characterized in that it is manufactured by the manufacturing method of the TiO 2 composite porous silica photocatalyst particles of the present invention.
（実施例１）
４４ｇのトリブロック共重合体Ｐｌｕｒｏｎｉｃ Ｆ１２７（組成；ＰＥＯ１０６ＰＰＯ７０ＰＥＯ１０６、重量平均分子量；１２，６００、親水部ＰＥＯ重量割合；７０％、ＢＡＳＦ社製）を、水１，５００ｇで希釈した６０質量％硝酸３７０ｇに溶解させ、前記トリブロック共重合体を含む第１の酸性溶液を調製した（トリブロック共重合体含有酸性溶液調製工程）。
次いで、前記第１の酸性溶液に富士化学社製ＴｉＯ２ゾルを２３．２ｇ加え、３５℃の温度条件下で攪拌混合して、ＴｉＯ２と前記トリブロック共重合体を含む第２の酸性溶液を調製した（ＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程）。ここで、前記ＴｉＯ２ゾルは、石原産業製光触媒酸化チタンＳＴ−０１を有機溶媒としてのイソプロパノールと分散剤としてのアセチルアセトンとの混合溶液中に分散させたもので、ゾル中ＴｉＯ２ナノ粒子を１０質量％含むものである。
次いで、水１，１１０ｇで希釈した１６０ｇのＪＩＳ３号水ガラス水溶液（ＳｉＯ２：２９．１質量％、Ｎａ２Ｏ：９．５質量％、Ｈ２Ｏ：６１．４質量％）を３５℃に調整し、撹拌しながら前記第２の酸性溶液中に添加して、水ガラス混合溶液を調製した（水ガラス混合工程）。この水ガラス混合溶液のモル比は、ＳｉＯ２を基準として、ＳｉＯ２：Ｐｌｕｒｏｎｉｃ Ｆ１２７：Ｎａ２Ｏ：ＨＮＯ３：Ｈ２Ｏ：ＴｉＯ２＝１：０．００４５：０．３１６：６．２５：１９９：０．０３８である。なお、このモル比におけるＨ２Ｏには、全ての原料由来の水を含めている。
次いで、前記水ガラス混合溶液を３５℃の温度条件下で４時間撹拌して反応させ、固形状の前駆体粒子を生成させた（前駆体粒子生成工程）。
最後に、濾別し、水で洗浄後乾燥させた前記前駆体を電気炉に入れ、６００℃の温度条件下で１時間焼成することで、前記前駆体粒子から前記トリブロック共重合体を気化させて除去し、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を得た（光触媒粒子形成工程）。
Example 1
44 g of triblock copolymer Pluronic F127 (composition: PEO 106 PPO 70 PEO 106 , weight average molecular weight: 12,600, hydrophilic part PEO weight ratio: 70%, manufactured by BASF) diluted with 1,500 g of water 60 A first acidic solution containing the triblock copolymer was prepared by dissolving in 370 g of mass% nitric acid (triblock copolymer-containing acidic solution preparation step).
Subsequently, 23.2 g of TiO 2 sol manufactured by Fuji Chemical Co., Ltd. is added to the first acidic solution, and the mixture is stirred and mixed under a temperature condition of 35 ° C., so that the second acidic solution containing TiO 2 and the triblock copolymer is mixed. was prepared (TiO 2 - triblock copolymer containing acidic solution preparation step). Here, the TiO 2 sol, obtained by dispersing manufactured by Ishihara Sangyo Kaisha, titanium oxide photocatalyst ST-01 in a mixed solution of the acetylacetone as isopropanol and a dispersant as an organic solvent, 10 to TiO 2 nanoparticles in the sol Including mass%.
Next, 160 g of JIS No. 3 water glass aqueous solution (SiO 2 : 29.1 mass%, Na 2 O: 9.5 mass%, H 2 O: 61.4 mass%) diluted with 1,110 g of water was brought to 35 ° C. It adjusted and added in the said 2nd acidic solution, stirring, and prepared the water glass mixed solution (water glass mixing process). The molar ratio of water glass mixed solution, a SiO 2 basis, SiO 2: Pluronic F127: Na 2 O: HNO 3: H 2 O: TiO 2 = 1: 0.0045: 0.316: 6.25: 199: 0.038. Note that H 2 O in this molar ratio includes water derived from all raw materials.
Next, the water glass mixed solution was stirred and reacted under a temperature condition of 35 ° C. for 4 hours to generate solid precursor particles (precursor particle generation step).
Finally, the precursor that has been filtered, washed with water and dried is placed in an electric furnace and calcined for 1 hour at a temperature of 600 ° C., thereby vaporizing the triblock copolymer from the precursor particles. Thus, TiO 2 composite porous silica photocatalyst particles according to Example 1 were obtained (photocatalyst particle forming step).
（実施例２）
実施例１のＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程におけるＴｉＯ２ゾルの添加量を２３．２ｇから４６．４ｇに変更したこと以外は、実施例１と同様にして、実施例２に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。
(Example 2)
Example 2 was performed in the same manner as in Example 1 except that the amount of TiO 2 sol added in the TiO 2 -triblock copolymer-containing acidic solution preparation step in Example 1 was changed from 23.2 g to 46.4 g. TiO 2 composite porous silica photocatalyst particles according to the above were produced.
（実施例３）
実施例１のＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程におけるＴｉＯ２ゾルの添加量を２３．２ｇから９２．８ｇに変更したこと以外は、実施例１と同様にして、実施例３に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。
(Example 3)
TiO 2 of Example 1 - was changed to 92.8g of 23.2g the amount of TiO 2 sol in triblock copolymer containing acidic solution preparation step, in the same manner as in Example 1, Example 3 TiO 2 composite porous silica photocatalyst particles according to the above were produced.
（参考例１）
実施例１のＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程を実施することなく、ＴｉＯ２ナノ粒子が含まれていない第１の酸性溶液に直接水ガラス水溶液を加えたこと以外は、実施例１と同様にして、参考例１に係る多孔質シリカ粒子を作製した。
(Reference Example 1)
Except that the aqueous solution of water glass was added directly to the first acidic solution containing no TiO 2 nanoparticles without carrying out the TiO 2 -triblock copolymer-containing acidic solution preparation step of Example 1. In the same manner as in Example 1, porous silica particles according to Reference Example 1 were produced.
（実施例４）
実施例１の光触媒粒子形成工程における前駆体粒子の焼成温度を６００℃から８００℃に変更したこと以外は、実施例１と同様にして、実施例４に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。
Example 4
TiO 2 composite porous silica photocatalyst particles according to Example 4 in the same manner as in Example 1, except that the firing temperature of the precursor particles in the photocatalyst particle forming step of Example 1 was changed from 600 ° C. to 800 ° C. Manufactured.
（実施例５）
実施例２の光触媒粒子形成工程における前駆体粒子の焼成温度を６００℃から８００℃に変更したこと以外は、実施例２と同様にして、実施例５に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。
(Example 5)
TiO 2 composite porous silica photocatalyst particles according to Example 5 in the same manner as in Example 2 except that the firing temperature of the precursor particles in the photocatalyst particle forming step of Example 2 was changed from 600 ° C. to 800 ° C. Manufactured.
（実施例６）
実施例３の光触媒粒子形成工程における前駆体粒子の焼成温度を６００℃から８００℃に変更したこと以外は、実施例３と同様にして、実施例６に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。
(Example 6)
TiO 2 composite porous silica photocatalyst particles according to Example 6 in the same manner as in Example 3 except that the firing temperature of the precursor particles in the photocatalyst particle forming step of Example 3 was changed from 600 ° C. to 800 ° C. Manufactured.
（参考例２）
参考例１において作製される前駆体粒子を８００℃の温度条件下で１時間焼成することで、参考例２に係る多孔質シリカ粒子を作製した。
(Reference Example 2)
Porous silica particles according to Reference Example 2 were prepared by firing the precursor particles prepared in Reference Example 1 at 800 ° C. for 1 hour.
（比較例１）
実施例１のＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程におけるＴｉＯ２ゾルを富士化学社製のものから石原産業社製ＳＴＳ−０１に代えたこと以外は、実施例１と同様にして、比較例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子の製造を試みた。
ここで、前記ＳＴＳ−０１は、石原産業社製の光触媒酸化チタンナノ粒子ＳＴ−０１を硝酸水溶液中に分散させた硝酸酸性で安定なＴｉＯ２ゾルである。
しかしながら、このＳＴＳ−０１を用いた場合、前駆体粒子生成工程において、シリカ粒子の形成は確認できたものの、ＴｉＯ２ナノ粒子はシリカ粒子と乖離することとなり、ＴｉＯ２ナノ粒子をシリカ骨格中に複合化することができなかった。
(Comparative Example 1)
TiO 2 of Example 1 - except that instead of the TiO 2 sol in triblock copolymer containing acidic solution preparation step from those of Fuji Chemical Co., Ltd. to Ishihara Sangyo Kaisha Ltd. STS-01, in the same manner as in Example 1 Then, production of TiO 2 composite porous silica photocatalyst particles according to Comparative Example 1 was attempted.
Here, the STS-01 is a nitric acid acidic and stable TiO 2 sol in which photocatalytic titanium oxide nanoparticles ST-01 manufactured by Ishihara Sangyo Co., Ltd. are dispersed in an aqueous nitric acid solution.
However, when this STS-01 was used, formation of silica particles was confirmed in the precursor particle generation step, but the TiO 2 nanoparticles were separated from the silica particles, and the TiO 2 nanoparticles were incorporated into the silica skeleton. Could not be combined.
（比較例２）
参考例１に係る多孔質シリカ粒子と、光触媒酸化チタンとしてのＤｅｇｕｓｓａ Ｐ２５（正式名称「ＡＥＲＯＸＩＤＥ ＴｉＯ２ Ｐ２５」、日本での供給元；日本アエロジル社）とを常温下ビーカー内で混ぜ合わせ、両者を物理的に混合させた比較例２に係るＴｉＯ２複合化多孔質シリカ光触媒粒子を製造した。なお、Ｄｅｇｕｓｓａ Ｐ２５の詳細については、後述の参考例３にて説明する。
(Comparative Example 2)
The porous silica particles according to Reference Example 1 and Degussa P25 (official name “AEROXIDE TiO 2 P25” as a photocatalytic titanium oxide, supplier in Japan; Nippon Aerosil Co., Ltd.) are mixed in a beaker at room temperature. TiO 2 composite porous silica photocatalyst particles according to Comparative Example 2 that were physically mixed were produced. Details of Degussa P25 will be described later in Reference Example 3.
（参考例３）
光触媒活性評価に広く使用されるＴｉＯ２ナノ粒子であるＤｅｇｕｓｓａ Ｐ２５を参考例３とした。このＤｅｇｕｓｓａ Ｐ２５は、アナターゼが８割程度含まれるルチルとの混合相で、１次粒子径が２１ｎｍ、比表面積が５０ｍ２／ｇであり、ＴｉＯ２としては、比表面積が比較的大きいことが特徴である。また、このＤｅｇｕｓｓａ Ｐ２５は、触媒学会で参照触媒（参照触媒；共通試料の無償提供とその資料のデータ収集を通して、触媒に関する研究活動をバックアップすることを目的として１９７９年に触媒学会により策定）として用いられている。強い光触媒活性を有するため、歴史的に光触媒の標準試料として用いられる。
(Reference Example 3)
Reference example 3 was Degussa P25, which is a TiO 2 nanoparticle widely used for photocatalytic activity evaluation. This Degussa P25 is a mixed phase with rutile containing about 80% of anatase, has a primary particle diameter of 21 nm, a specific surface area of 50 m 2 / g, and has a relatively large specific surface area as TiO 2. It is. This Degussa P25 is used as a reference catalyst by the Catalysis Society of Japan (reference catalyst; formulated by the Catalysis Society of Japan in 1979 for the purpose of backing up research activities related to catalysts through free provision of common samples and data collection of the materials). It has been. Since it has strong photocatalytic activity, it has historically been used as a standard sample for photocatalysts.
（測定方法及び評価結果）
＜比表面積及び細孔径分布＞
日本ベル社製ＢＥＬＳＯＲＰ Ｍｉｎｉを使用し、液体窒素温度で測定した窒素吸着等温線から、実施例１〜６及び比較例１、２に係るＴｉＯ２複合化多孔質シリカ光触媒粒子（比較例１については、多孔質シリカ粒子）のＢＥＴ比表面積を算出した。
また、前記窒素吸着等温線にＢＪＨ法を適用して得られた細孔径分布からメソ孔直径を求めた。更にｔ−プロット法により、実施例１〜６及び比較例１、２に係るＴｉＯ２複合化多孔質シリカ光触媒粒子（比較例１については、多孔質シリカ粒子）の全細孔容積及びマイクロポア容積を算出した。メソ細孔容積は前者から後者を差し引いて求められる。
以上の算出結果を下記表１に示す。
(Measurement method and evaluation results)
<Specific surface area and pore size distribution>
TiO 2 composite porous silica photocatalyst particles according to Examples 1 to 6 and Comparative Examples 1 and 2 (for Comparative Example 1) from a nitrogen adsorption isotherm measured at a liquid nitrogen temperature using BELSORP Mini manufactured by Bell Japan , Porous silica particles) was calculated.
The mesopore diameter was determined from the pore size distribution obtained by applying the BJH method to the nitrogen adsorption isotherm. Further, the total pore volume and micropore volume of the TiO 2 composite porous silica photocatalyst particles according to Examples 1 to 6 and Comparative Examples 1 and 2 (for the Comparative Example 1, porous silica particles) by t-plot method. Was calculated. The mesopore volume is obtained by subtracting the latter from the former.
The above calculation results are shown in Table 1 below.
表１に示すように、焼成の温度条件を６００℃とした実施例１〜３では、焼成の温度条件を８００℃とした実施例４〜６よりも、比表面積、全細孔容積、メソ孔容積、マイクロ孔容積及びメソ孔直径のいずれにおいても、焼成の温度条件を８００℃とした実施例４〜６より大きな値が得られている。
また、参考例１及び実施例１〜３、参考例２及び実施例４〜６の結果から理解されるように、ＴｉＯ２を含まない純粋な多孔質シリカと、ＴｉＯ２含有率の低い多孔質シリカとでは、細孔特性に大きな変化は認められない。しかし、ＴｉＯ２の含有率が増加するに伴い、細孔特性に変化が見られ、２０重量％近くになると、相対的に大きな差異が認められるようになる。
なお、焼成条件を８００℃とした参考例２及び実施例４〜６の結果から、ＴｉＯ２の共存が耐熱性の向上に寄与していると考えられる。
As shown in Table 1, the specific surface area, the total pore volume, and the mesopores in Examples 1 to 3 in which the firing temperature condition was 600 ° C. were higher than those in Examples 4 to 6 in which the firing temperature condition was 800 ° C. In all of the volume, the micropore volume, and the mesopore diameter, values larger than those in Examples 4 to 6 in which the temperature condition for firing was set to 800 ° C were obtained.
Also, Reference Example 1 and Examples 1 to 3, as will be understood from the results of Reference Example 2 and Example 4-6, and the pure porous silica containing no TiO 2, low TiO 2 content porous There is no significant change in pore characteristics with silica. However, as the content of TiO 2 increases, the pore characteristics change, and when it is close to 20% by weight, a relatively large difference is recognized.
In addition, from the results of Reference Example 2 and Examples 4 to 6 in which the firing condition is 800 ° C., it is considered that the coexistence of TiO 2 contributes to the improvement of heat resistance.
＜Ｘ線回析＞
リガク社製ＳｍａｒｔＬａｂを使用し、ＣｕＫα線源、加速電圧４０ｋＶ、３０ｍＡの測定条件でＸ線回折測定（ＸＲＤ）を行った。結晶子の大きさは、（２００）面の回折ピークにＳｃｈｅｒｒｅｒの式を適用して算出した。
<X-ray diffraction>
Using Rigaku SmartLab, X-ray diffraction measurement (XRD) was performed under the measurement conditions of a CuKα radiation source, an acceleration voltage of 40 kV, and 30 mA. The crystallite size was calculated by applying the Scherrer equation to the diffraction peak of the (200) plane.
図２（ａ）、（ｂ）に実施例１〜３に係るＴｉＯ２複合化多孔質シリカ光触媒粒子のＸＲＤパターンを示す。図２（ａ）は、低角のＸＲＤパターンを示し、図２（ｂ）は、高角のＸＲＤパターンを示す。
図２（ａ）に示す低角のＸＲＤピークは、細孔配列の規則性の程度を示している。ＴｉＯ２の含有率が増加するに従い、ピークがブロード化し、１本になり、規則性が低下することが確認される。
また、図２（ｂ）に示すように、実施例１〜３に係るＴｉＯ２複合化多孔質シリカ光触媒粒子は、回折角（２θ）が５度以下の範囲にＸ線回折の回折ピークが少なくとも１本認められる。この回折ピークは、ＴＥＭ像観察、吸着法による解析結果を考慮すると、ＴｉＯ２以外の物質構造に起因するもので、本光触媒粒子では非晶質ＳｉＯ２によって形成される壁構造の規則性すなわち細孔が規則的に配列していることを明示していることから、メソポアが規則性をもって配列されていることを示す。
また、前述のＢＪＨ解析に基づき作成した細孔径分布曲線を図３に示す。図３では、図２（ａ）に示す規則性の低下に伴い、ＴｉＯ２の含有率が増加するに従って細孔径分布が広くなり、大きさの均一性も低下することが確認される。
なお、図２（ｂ）に示す各ピークは、ＴｉＯ２のアナターゼ結晶構造を示している。
2A and 2B show XRD patterns of the TiO 2 composite porous silica photocatalyst particles according to Examples 1 to 3. FIG. 2A shows a low angle XRD pattern, and FIG. 2B shows a high angle XRD pattern.
The low-angle XRD peak shown in FIG. 2A shows the degree of regularity of the pore arrangement. It is confirmed that as the content of TiO 2 increases, the peak broadens and becomes one, and the regularity decreases.
Further, as shown in FIG. 2B, the TiO 2 composite porous silica photocatalyst particles according to Examples 1 to 3 have at least a diffraction peak of X-ray diffraction in a range where the diffraction angle (2θ) is 5 degrees or less. One is allowed. This diffraction peak is caused by the substance structure other than TiO 2 in consideration of the TEM image observation and the analysis result by the adsorption method. In the present photocatalyst particle, the regularity of the wall structure formed by amorphous SiO 2 , that is, the fine structure. The fact that the pores are regularly arranged indicates that the mesopores are regularly arranged.
Moreover, the pore diameter distribution curve created based on the above-mentioned BJH analysis is shown in FIG. In FIG. 3, it is confirmed that the pore diameter distribution becomes wider and the size uniformity decreases as the content of TiO 2 increases as the regularity shown in FIG.
Each peak shown in FIG. 2 (b) shows the anatase crystal structure of TiO 2.
＜高分解能電子顕微鏡像＞
ＦＥＩ社製電界放射型透過型電子顕微鏡ＴｅｃｎａｉＧ２Ｆ２０を使用し、加速電圧２００ｋＶで、透過電子像観察（ＴＥＭ観察）を行った。
<High resolution electron microscope image>
Using a field emission type transmission electron microscope TecnaiG2F20 manufactured by FEI, transmission electron image observation (TEM observation) was performed at an acceleration voltage of 200 kV.
図４（ａ）〜図６（ｂ）に、実施例１〜３に係るＴｉＯ２複合化多孔質シリカ光触媒粒子のＴＥＭ像を示す。なお、図４（ａ）は、実施例１、図５（ａ）は、実施例２、図６（ａ）は、実施例３に関するＴＥＭ像を示し、図４（ｂ）は、実施例１、図５（ｂ）は、実施例２、図６（ｂ）は、実施例３に関する部分拡大像を示す。 4 (a) to 6 (b) show TEM images of the TiO 2 composite porous silica photocatalyst particles according to Examples 1 to 3. FIG. 4A shows a TEM image related to Example 1, FIG. 5A shows Example 2 and FIG. 6A shows Example 3 and FIG. 4B shows Example 1. FIG. 5B shows a partially enlarged image related to the second embodiment and FIG. 6B shows a partially enlarged image related to the third embodiment.
図４（ａ）〜図６（ｂ）から、ＴｉＯ２ナノ粒子は、ナノサイズの大きさを保持したまま、細孔を閉塞することなくシリカ表面に高分散状態で存在することが確認される。なお、ＸＲＤ回折ピークから求めたＴｉＯ２ナノ粒子の大きさは６００℃で約７nmと元の大きさを保持し、８００℃では粒成長して約１５ｎｍに増大することから、ＴｉＯ２ナノ粒子は、細孔径３．５（実施例１）よりも大きいことから、細孔内ではなく、１次粒子の外側に存在する。ＴｉＯ２ナノ粒子が細孔外に担持されると、細孔内に担持される場合と比較して、細孔入り口及び細孔内部の閉塞あるいは細孔表面の平滑性を損なうことがなく、分解対象分子の吸着及び脱着が容易で、しかも照射光を有効に受けることが可能であることから、より高活性な光触媒サイトとしての役割を担うことができる。
また、図４（ａ）〜図６（ｂ）のＴＥＭ像分析、及び図２（ａ）、図２（ｂ）のＸＲＤパターン分析から、ＴｉＯ２ナノ粒子の担持量が少ない場合、純粋な多孔質シリカのメソポーラス構造がそのまま反映され、細孔構造は、体心立方晶系の規則配列を有することが認められる。
しかし、ＴｉＯ２ナノ粒子の担持量が多くなるに伴い、幅広い１本のＸＲＤ回折ピークが低角に認められることから、メソポーラス構造の規則性が低くなり、これに伴い細孔分布もブロード化することが分かる（図２（ａ）、図３参照）。
このことから、用いるＴｉＯ２ナノ粒子の量が少ない場合、１次粒子である前述のメソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］の規則性を損なうことなく、ＴｉＯ２ナノ粒子が高分散化して１次粒子と複合化し、１次粒子間の衝突によって集合し、２次粒子が生成されると考えられる（図１（ｄ）参照）。
一方、用いるＴｉＯ２ナノ粒子の量が多い場合、ＴｉＯ２ナノ粒子とメソポーラス構造前駆体［Ｎ０Ｈ＋］［Ｘ−Ｉ＋］の相互作用が顕著となり、これらの複合化によって、規則性の低い１次粒子が形成され、更に集合して２次粒子が生成されると推定される。
4 (a) to 6 (b), it is confirmed that the TiO 2 nanoparticles are present in a highly dispersed state on the silica surface without blocking the pores while maintaining the nano-sized size. . The size of the TiO 2 nanoparticles obtained from XRD diffraction peak retained about 7nm and original size at 600 ° C., since it increases approximately 15nm and at 800 ° C. grain growth, TiO 2 nanoparticles Since the pore diameter is larger than 3.5 (Example 1), it exists outside the primary particles, not inside the pores. When the TiO 2 nanoparticles are supported outside the pores, they are decomposed without impairing the pore entrance and the inside of the pores or the smoothness of the pore surface as compared with the case where they are supported inside the pores. Since the target molecule can be easily adsorbed and desorbed and can receive irradiation light effectively, it can serve as a more highly active photocatalytic site.
Further, from the TEM image analysis of FIGS. 4 (a) to 6 (b) and the XRD pattern analysis of FIGS. 2 (a) and 2 (b), when the amount of TiO 2 nanoparticles supported is small, pure porosity It is recognized that the mesoporous structure of porous silica is reflected as it is, and the pore structure has a regular arrangement of body-centered cubic system.
However, as the amount of TiO 2 nanoparticles supported increases, a wide single XRD diffraction peak is observed at a low angle, so the regularity of the mesoporous structure is lowered, and the pore distribution is also broadened accordingly. It can be seen (see FIGS. 2A and 3).
From this, when the amount of TiO 2 nanoparticles used is small, the TiO 2 nanoparticles can be obtained without impairing the regularity of the aforementioned mesoporous structure precursor [N 0 H + ] [X − I + ] as primary particles. Is highly dispersed and combined with primary particles, and is aggregated by collisions between the primary particles to generate secondary particles (see FIG. 1D).
On the other hand, when the amount of TiO 2 nanoparticles to be used is large, the interaction between the TiO 2 nanoparticles and the mesoporous structure precursor [N 0 H + ] [X − I + ] becomes remarkable. It is presumed that low primary particles are formed and further aggregated to produce secondary particles.
＜光触媒能評価＞
ＪＩＳ Ｒ１７０１−２に準拠して平板流通法により光触媒能の評価を行った。
具体的には、実施例１〜６及び比較例２に係るＴｉＯ２複合化多孔質シリカ光触媒粒子（ただし、実施例４を除く）各１ｇに、純水を滴下してペースト状に分散したサンプルを、５０ｍｍ×１００ｍｍのセラミックス板上に薄く、できるだけ均一になるように塗布して、空気中で乾燥後、紫外線ランプ照射下で前処理を１日間行い、不純物による影響を取り除いた。その後、このセラミックス基板を光照射反応装置のリアクター内に設置して、濃度５ｐｐｍのアセトアルデヒド（相対湿度５０％）の原料ガスを流速１Ｌ／ｍｉｎで流通させ、リアクターの上部から紫外線ランプにより紫外光を照射した。なお、比較例１に係る多孔質シリカ粒子については、ＴｉＯ２ナノ粒子が含まれないため、光触媒能評価を行わなかった。
初期濃度５ｐｐｍのアセトアルデヒドは、紫外光照射開始９０分前からリアクターに流通させ、紫外光照射は、照射開始（反応時間０とする）後、１８０分間照射した後で停止させた。紫外光照射の停止後、原料ガスを３０分間リアクターに流通させ、その後、バイパスに原料ガスの流路を切り替え３０分後に評価試験を終了させた。
流通後のアセトアルデヒド濃度を５分間毎にＦＩＤ方式によりガスクロマトグラフィーで分析すると同時に、発生したＣＯ２濃度を米国サーモ社製４１Ｃ−ＣＯ２モニターで連続的に計測し、アセトアルデヒドの分解率と転換率を求めた。転換率は、アセトアルデヒドの流通濃度と発生するＣＯ２濃度の割合から求めた。完全分解、即ち、転換率１００％では、分解成分がＣＯ２とＨ２Ｏだけで副生成物の発生が認められないことから、化学量論比でアセトアルデヒド量の２倍のＣＯ２が発生することになる。
<Evaluation of photocatalytic activity>
Based on JIS R1701-2, the photocatalytic ability was evaluated by a flat plate flow method.
Specifically, a sample in which pure water was dropped into 1 g of each of TiO 2 composite porous silica photocatalyst particles (excluding Example 4) according to Examples 1 to 6 and Comparative Example 2 and dispersed in a paste form. Was applied on a 50 mm × 100 mm ceramic plate so as to be as uniform as possible, dried in air, and pretreated for 1 day under irradiation with an ultraviolet lamp to remove the influence of impurities. After that, this ceramic substrate is placed in the reactor of the light irradiation reaction apparatus, and a source gas of acetaldehyde having a concentration of 5 ppm (relative humidity 50%) is circulated at a flow rate of 1 L / min, and ultraviolet light is emitted from the upper part of the reactor by an ultraviolet lamp. Irradiated. Note that the porous silica particles according to Comparative Example 1, because it does not contain TiO 2 nanoparticles was not performed photocatalytic activity evaluation.
Acetaldehyde with an initial concentration of 5 ppm was allowed to flow through the reactor 90 minutes before the start of ultraviolet light irradiation, and the ultraviolet light irradiation was stopped after irradiation for 180 minutes after the start of irradiation (reaction time 0). After the ultraviolet light irradiation was stopped, the raw material gas was circulated through the reactor for 30 minutes, and then the flow of the raw material gas was switched to the bypass, and the evaluation test was terminated after 30 minutes.
Analyzing the acetaldehyde concentration after distribution by gas chromatography using the FID method every 5 minutes, and simultaneously measuring the generated CO 2 concentration with a 41C-CO 2 monitor manufactured by Thermo Corporation, USA, the decomposition rate and conversion rate of acetaldehyde Asked. The conversion rate was determined from the ratio of the distribution concentration of acetaldehyde and the generated CO 2 concentration. With complete decomposition, that is, with a conversion rate of 100%, the decomposition components are only CO 2 and H 2 O, and generation of by-products is not observed. Therefore, CO 2 is generated in a stoichiometric ratio that is twice the amount of acetaldehyde. It will be.
図７に、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子の光触媒能特性を示す。なお、該図７中、太線がアセトアルデヒド濃度の推移を示し、細線がＣＯ２濃度の推移を示す。
該図７に示されるように、紫外光照射９０分前からの接触でアセトアルデヒド濃度は、５ｐｐｍから２ｐｐｍまで大きく減少し、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子は、流通下でも分解対象物質を吸着させやすく、大きな動的吸着能を有していることが明瞭である。吸着飽和に達した後に紫外光を開始すると（図７中の０ｍｉｎ）、１．２ｐｐｍまでアセトアルデヒド濃度が低下し、この状態が紫外光を照射する間継続されていた。紫外光の照射を止めると（図７中の１８０ｍｉｎ）、アセトアルデヒド濃度は、初期濃度の５ｐｐｍに戻り、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子によるアセトアルデヒド分解量は、約３．８ｐｐｍで、分解率は、約７５％である。
一方、ＣＯ２濃度は、紫外光照射（図７中の０ｍｉｎ）と同時に上昇し、ＣＯ２の発生が続き、紫外光を照射する間大凡１３ｐｐｍを保持していた。ベースラインは、５ｐｐｍで、アセトアルデヒドの光触媒反応に伴って分解量の２倍に相当する約８ｐｐｍのＣＯ２の発生を確認でき、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子は、アセトアルデヒドを完全分解していることが分かる。
なお、図７中の−６０ｍｉｎの時点で、ＣＯ２濃度が上昇しているが、これは、バイパスからリアクターに四方バルブを切り替える際、リアクター内部に存在していたＣＯ２が押し出される測定上の理由に基づくものであり、実施例１に係るＴｉＯ２複合化多孔質シリカ光触媒粒子の光触媒能特性によるものではない。
FIG. 7 shows the photocatalytic performance characteristics of the TiO 2 composite porous silica photocatalyst particles according to Example 1. In FIG. 7, the thick line shows the transition of the acetaldehyde concentration, and the thin line shows the transition of the CO 2 concentration.
As shown in FIG. 7, the acetaldehyde concentration is greatly reduced from 5 ppm to 2 ppm by contact from 90 minutes before the ultraviolet light irradiation, and the TiO 2 composite porous silica photocatalyst particles according to Example 1 are in circulation. It is clear that the substance to be decomposed is easily adsorbed and has a large dynamic adsorption ability. When ultraviolet light was started after reaching adsorption saturation (0 min in FIG. 7), the acetaldehyde concentration decreased to 1.2 ppm, and this state was continued while the ultraviolet light was irradiated. When the ultraviolet light irradiation was stopped (180 min in FIG. 7), the acetaldehyde concentration returned to the initial concentration of 5 ppm, and the amount of acetaldehyde decomposed by the TiO 2 composite porous silica photocatalyst particles according to Example 1 was about 3.8 ppm. The decomposition rate is about 75%.
On the other hand, the CO 2 concentration increased simultaneously with the irradiation with ultraviolet light (0 min in FIG. 7), the generation of CO 2 continued, and was maintained at approximately 13 ppm during the irradiation with ultraviolet light. The baseline was 5 ppm, and the generation of about 8 ppm CO 2 corresponding to twice the amount of decomposition accompanying the photocatalytic reaction of acetaldehyde could be confirmed. The TiO 2 composite porous silica photocatalyst particles according to Example 1 were acetaldehyde. It can be seen that is completely decomposed.
Note that the CO 2 concentration increases at the time of −60 min in FIG. 7, but this is due to measurement in which CO 2 existing inside the reactor is pushed out when the four-way valve is switched from the bypass to the reactor. This is based on the reason and is not based on the photocatalytic properties of the TiO 2 composite porous silica photocatalyst particles according to Example 1.
また、実施例２から６に係るＴｉＯ２複合化多孔質シリカ光触媒粒子においても、ＴｉＯ２ナノ粒子の含有率によらず、いずれも高いアセトアルデヒド分解率と完全分解挙動を示した。
各ＴｉＯ２複合化多孔質シリカ光触媒粒子のアセトアルデヒド分解率を下記表２に示す。
Also, the TiO 2 composite porous silica photocatalyst particles according to Examples 2 to 6 all showed high acetaldehyde decomposition rate and complete decomposition behavior regardless of the content of TiO 2 nanoparticles.
The acetaldehyde decomposition rate of each TiO 2 composite porous silica photocatalyst particle is shown in Table 2 below.
以上のように、本発明のＴｉＯ２複合化多孔質シリカ光触媒粒子は、分解対象物質に対する大きな動的吸着能を有するとともに、分解対象物質に対する優れた分解能を有する。また、本発明のＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法によれば、短時間かつ低温の生成条件で効率良くＴｉＯ２複合化多孔質シリカ光触媒粒子を製造することができる。 As described above, the TiO 2 composite porous silica photocatalyst particles of the present invention have a large dynamic adsorption ability for the decomposition target substance and an excellent resolution for the decomposition target substance. Further, according to the manufacturing method of the TiO 2 composite porous silica photocatalyst particles of the present invention can be produced efficiently TiO 2 composite porous silica photocatalyst particles short time and at a low temperature of production conditions.
Claims (3)
細孔形成剤としてポリプロピレンオキシドの重量平均分子量が２，５００以上で、ポリエチレンオキシドの重合割合が４０％以上のポリエチレンオキシド−ポリプロピレンオキシド−ポリエチレンオキシド（ＰＥＯ−ＰＰＯ−ＰＥＯ）であるトリブロック共重合体を硝酸水溶液に添加して溶解させ、前記トリブロック共重合体を含む第１の酸性溶液を調製するトリブロック共重合体含有酸性溶液調製工程と、
前記ＴｉＯ２ナノ粒子がアセチルアセトンにより炭素数１〜４の低級アルコール中に分散されたＴｉＯ２ゾルを前記第１の酸性溶液に添加し、前記ＴｉＯ２ナノ粒子及び前記トリブロック共重合体を含有する第２の酸性溶液を調製するＴｉＯ２−トリブロック共重合体含有酸性溶液調製工程と、
前記第２の酸性溶液とシリカ源としての水ガラス水溶液とを混合し、水ガラス混合液を調製する水ガラス混合工程と、
前記水ガラス混合液を２５℃〜４０℃の温度条件下で１時間〜６時間撹拌し、シリカ母材の外壁に前記トリブロック共重合体が規則配列された粒子の表面に前記ＴｉＯ２ナノ粒子が担持された１次粒子が凝集した２次粒子の前駆体粒子を形成する前駆体粒子形成工程と、
前記水ガラス混合液から分離された前記前駆体粒子を４００℃〜１，０００℃の温度条件下で０．５時間〜６時間焼成して前記前駆体粒子から前記トリブロック共重合体を除去し、前記ＴｉＯ２複合化多孔質シリカ光触媒粒子を形成する光触媒粒子形成工程と、
を含むことを特徴とするＴｉＯ２複合化多孔質シリカ光触媒粒子の製造方法。 Porous structure in which mesopores and micropores coexist, and the mesopores are regularly arranged so that at least one diffraction peak is observed at a diffraction angle (2θ) of 5 degrees or less in an X-ray diffraction pattern using a CuKα radiation source. A method for producing TiO 2 composite porous silica photocatalyst particles having TiO 2 nanoparticles supported on the outer surface of the pores of silica particles and exhibiting photocatalytic activity,
A triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) having a weight average molecular weight of 2,500 or more as a pore-forming agent and a polymerization ratio of polyethylene oxide of 40% or more. A triblock copolymer-containing acidic solution preparation step of preparing a first acidic solution containing the triblock copolymer,
Was added TiO 2 sol which the TiO 2 nanoparticles dispersed in a lower alcohol of 1-4 carbon atoms by acetylacetone in the first acidic solution, containing the TiO 2 nanoparticles and the triblock copolymer A TiO 2 -triblock copolymer-containing acidic solution preparation step for preparing a second acidic solution;
A water glass mixing step of mixing the second acidic solution and a water glass aqueous solution as a silica source to prepare a water glass mixed solution;
The water glass mixture is stirred for 1 to 6 hours under a temperature condition of 25 ° C. to 40 ° C., and the TiO 2 nanoparticles are formed on the surface of the particles in which the triblock copolymer is regularly arranged on the outer wall of the silica base material. A precursor particle forming step of forming precursor particles of secondary particles in which primary particles on which the particles are supported are aggregated;
The precursor particles separated from the water glass mixture are calcined at 400 ° C. to 1,000 ° C. for 0.5 hours to 6 hours to remove the triblock copolymer from the precursor particles. A photocatalyst particle forming step of forming the TiO 2 composite porous silica photocatalyst particles;
TiO 2 The method of producing a composite of a porous silica photocatalyst particles, which comprises a.
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