Laser Ablation Nanoarchitectonics of Au-Cu Alloys Deposited on TiO 2 Photocatalyst Films for Switchable Hydrogen Evolution from Formic Acid Dehydrogenation.

The regulation of H 2 evolution from formic acid dehydrogenation using recyclable photocatalyst films is an essential approach for on-demand H 2 production. We have successfully generated Au-Cu nanoalloys using a laser ablation method and deposited them on TiO 2 photocatalyst films (Au x Cu 100- x /TiO 2 ). The Au-Cu/TiO 2 films were employed as photocatalysts for H 2 production from formic acid dehydrogenation under light-emitting diode (LED) irradiation (365 nm). The highest H 2 evolution rate for Au 20 Cu 80 /TiO 2 is archived to 62,500 μmol h -1 g -1 per photocatalyst weight. The remarkable performance of Au 20 Cu 80 /TiO 2 may account for the formation of Au-rich surfaces and the effect of Au alloying that enables Cu to sustain the metallic form on its surface. The metallic Au-Cu surface on TiO 2 is vital to supply the photoexcited electrons of TiO 2 to its surface for H 2 evolution. The rate-determining step (RDS) is identified as the reaction of a surface-active species with protons. The results establish a practical preparation of metal alloy deposited on photocatalyst films using laser ablation to develop efficient photocatalysts.