Inhibition of H2-O2 recombination using amino functional groups to anchor oxygen for enhancing photocatalytic hydrogen generation

Abstract

The recombination reaction of hydrogen and oxygen on the photocatalyst surface is a universal phenomenon, and it competes with the photocatalytic water splitting. To improve the photocatalytic hydrogen production efficiency, the rapid and effective separation of generated hydrogen and oxygen is one of the important means to inhibit this reverse reaction. Herein, theoretical simulation find that the amino-functionalized titanium dioxide (AF-TiO2) has excellent thermodynamic stability, and shows a strong oxygen adsorption capacity as well as is easy to release hydrogen compared with bare TiO2. So the amino functional groups on the catalyst surface can be used as an anchor sites for oxygen to separate well hydrogen and oxygen. Based on the theoretical results, the amide-functionalized AF-TiO2/Pt photocatalyst is synthesized by solvothermal method. A series of structural tests find that the AF-TiO2/Pt surface contains abundant and stable amide groups, which act as oxygen adsorption sites to reduce hydrogen-oxygen recombination. Therefore, AF-TiO2/Pt catalyst shows a high and stable photocatalytic hydrogen production activity under UV light triggering in pure water, which is 14.25 times than the H2 evolved over TiO2/Pt. Research ideas and design methods in this paper might provide a new way for the preparing solar-driven high active photocatalyst.