A facile approach for surface modification of TiO2 nanosheets to enhance photocatalytic hydrogen evolution activity

TiO2 nanosheets have a great potential in photocatalytic H2 evolution, but they suffer from low catalytic activity at present. Although the surface modification has been extensively used to improve the catalytic performance, regulating the surface functional groups of TiO2 nanosheets to enhance the photocatalytic activity has been largely overlooked. In this study, we attempt to tailor the surface properties of TiO2 nanosheets by adjusting the surface functional groups so as to improve their photocatalytic H2 production activity. With adding a small amount of alcohols in the synthesis system, the surface hydroxyl groups of TiO2 nanosheets were regulated successfully. Interestingly, the TiO2 nanosheets prepared with adding ethylene glycol possess the significantly more surface hydroxyl groups and exhibit a narrower bandgap, a higher hydrophilicity, and a slower recombination rate of photo-induced carriers than the conventional nanosheets. Benefit from these special properties, the ability of the hydroxyl-rich TiO2 nanosheets to photocatalyze H2 evolution is obviously improved.