Laser Ablation Nanoarchitectonics of Au-Cu Alloys Deposited on TiO₂ Photocatalyst Films for Switchable Hydrogen...

The regulation of H₂ evolution from formic acid dehydrogenation using recyclable photocatalyst films is an essential approach for on-demand H₂ production. We have successfully generated Au-Cu nanoalloys using a laser ablation method and deposited them on TiO₂ photocatalyst films (Au Cu_100- /TiO₂). The Au-Cu/TiO₂ films were employed as photocatalysts for H₂ production from formic acid dehydrogenation under light-emitting diode (LED) irradiation (365 nm). The highest H₂ evolution rate for Au₂₀Cu₈₀/TiO₂ is archived to 62,500 μmol h^-1 g^-1 per photocatalyst weight. The remarkable performance of Au₂₀Cu₈₀/TiO₂ 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 TiO₂ is vital to supply the photoexcited electrons of TiO₂ to its surface for H₂ 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.