Interesting molecular adsorption strategy induced surface charge redistribution of commercial TiO2: Boosting 9 times photocatalytic hydrogen production performance

Abstract

A higher conduction band position and more photogenerated electrons are distinctly important for the high-efficiency photocatalytic hydrogen evolution performance. However, raising conduction band position will enlarge the band gap and reduce the production of photogenerated electrons. Herein, a super simple and efficient ammonia molecular adsorption strategy was proposed and designed to promote efficient hydrogen production by a simple ammonia molecules adsorption on commercial TiO2 surface. The experimental and theoretical calculation results indicated that aniline can be successfully adsorbed on TiO2 surface by a straightforward mechanical grinding method, and the photocatalytic hydrogen production performance of TiO2 can be improved by more than 9 times after the adsorption of aniline. This is because the adsorbed aniline can provide electrons to the TiO2 surface and lead to a charge redistribution and accumulation on the surface of TiO2. Excessive electrons make the conduction band of TiO2 bend upward, thus improving the photogenerated electron reduction ability and the photocatalytic performance of TiO2. In addition, the adsorption of aniline enables TiO2 to show light absorption in the visible region, generating more photogenerated electrons to participate in the photocatalytic water splitting reaction. In this work, the molecular adsorption strategy is not only simple to operate, but also can improve the photoreduction ability and surface charge quantity of materials. It provides a simple and efficient new method for photocatalyst modification in addition to the traditional modification methods such as doping compounds.