Phase control and induction of visible-light photocatalytic activity in hierarchical porous structure nanocrystalline TiO2 prepared using a MOF-5-derived nanoporous carbon template

Abstract

BackgroundNanocasting is a powerful method to induce unique structural and morphological characteristics. It is known that the phase, morphology, and nanostructure of TiO2 facilitate its photocatalytic performance and band gap energy. In this context, we simultaneously controlled the TiO2 phase and improved its photocatalytic activity by choosing the appropriate carbon substrate and synthesis process. MethodsIn this study, a high surface area nanoporous carbon with an extremely interconnected mesoporous network and accessible pores in terms of depth and size was derived from MOF-5. This hard template used for the synthesis of titanium oxide (TiO2) nanoparticles by nanocasting. in addition to the anatase phase, the brookite phase was successfully produced using this nanocasting approach by penetrating NaF solution to the template pores under hydrothermal conditions. Significant FindingsThe results showed that, the interconnected mesoporous network of the carbon template led to the formation of brookite and anatase TiO2 with highly developed mesoporous and macroporous structures and very high surface areas of 109 and 126 m2g−1, respectively. Furthermore, the fabricated brookite and anatase showed enhanced photocatalytic efficiency in visible light because of the increase in light harvesting ability and the reduction in band gap energy to 2.84 and 2.60 eV, respectively.