Enhanced photocatalytic hydrogen production by loading histidine on TiO2

Although TiO2 exhibits excellent photocatalytic properties, its application has been limited owing to rapid e(-)/h(+) recombination. Therefore, TiO2 has failed to reach the desired effect in terms of efficient photocatalytic hydrogen production. In this study, a range of titanium dioxide catalysts loaded with histidine (His) were prepared by an easy dipping method, viz. by treating TiO2 in His aqueous solutions with different concentrations at ambient temperature. Photocatalytic hydrogen evolution by splitting water was performed on His-modified TiO2 under 300-W Xe irradiation. His-loaded TiO2 catalysts exhibited improved photocatalytic performance compared with pristine TiO2; TiO2 treated in 1 x 10(-3) mol center dot L-1 His showed the highest photocatalytic H-2 evolution activity (4.77 mu mol g(-1) h(-1) gm(-2)), which was 3.77 times higher than that of pure TiO2. Infrared and XPS analysis showed that His was successfully combined to the TiO2 surface by hydrogen bonding, constructing a fast channel for interfacial charge transfer. In the photocatalytic process, the photogenerated holes could migrate from the valence band of TiO2 to the highest occupied molecular orbital of His, which reduced the recombination rate of photogenerated e(-)/h(+) pairs, consequently, improved H-2 production efficiency. Importantly, the composite catalyst exhibited no decline in photocatalytic activity over 30 h of operation. This research provides an alternative approach for creating high-efficiency photocatalysts for H-2 production.

Automated summary

This study successfully improved the photocatalytic performance of TiO2 by loading histidine, which enhanced hydrogen production efficiency and maintained catalytic activity over 30 hours of operation.