Stable Ti3+ Defects in Oriented Mesoporous Titania Frameworks for Efficient Photocatalysis

Abstract By introducing a compatible reducing agent (2‐ethylimidazole) into a mono‐micelle assembly process, we present a type of ordered mesoporous TiO 2 microspheres that combines radially aligned mesostructure with Ti 3+ defects in mesoporous frameworks. Such reductant acts as a building block of mesostructured frameworks and reduces Ti 4+ in situ to generate defects during calcination, giving rise to the coexistence of bulk Ti 3+ defects and an ordered mesostructure. The mesoporous TiO 2 has both excellent mesoporosity (a high surface area of 106 m 2 g −1 , a mean pore size of 18.4 nm) and stable defects with an extended photoresponse. Such integration of unique mesoscopic architecture and atomic vacancies provide both effective mass transportation and enhanced light utilization, leading to a remarkable increase in H 2 generation rate. A maximum H 2 evolution rate of 19.8 mmol g −1 h −1 can be achieved, along with outstanding stability under solar light.