(40h) Synthesis of Highly Crystalline Mesoporous Transition Metal Oxides Using Laboratory Made Diblock Copolymer as Structure Directing Agent and Their Application to Photocatalyst
Highly crystalline and thermally stable mesoporous titanium oxide and niobium oxide with uniform pores have been synthesized by using laboratory made poly(ethylene oxide)-b-polystyrene(PEO-b-PS) diblock copolymers as structure directing agent. The amphiphilic diblock copolymers with various molecular weights were prepared through simple synthetic method called atom transfer radical polymerization (ATRP). This method can be easily applicable to researchers without any experiences in polymer synthesis. Pore size of transition metal oxides can be also easily controlled by changing the molecular weight of structure directing agent, PEO-b-PS. The photocatalytic activity of prepared TiO2 (CASH-TiO2) for water splitting and Methylene Blue degradation was studied and the TiO2 (P123-TiO2) templated by commercial triblock copolymer Pluronic P123 was used for comparison. The photocatalytic activity of CASH-TiO2 was about 2 times higher than that of P123-TiO2 in both hydrogen evolution and MB degradation. Though CASH-TiO2 has smaller surface area than the P123-TiO2, it exhibited high activity due to efficient charge transfer resulting from high crystallinity of mesostructured walls.