Subnano-Sized Pt-Au Alloyed Clusters as Enhanced Cocatalyst for Photocatalytic Hydrogen Evolution

Photocatalytic water splitting for H₂ evolution is regarded as the most promising way to overcome the energy and environmental crisis. Pt clusters as a cocatalyst can efficiently enhance the performance of H₂ generation in most photocatalysts, but the activity is still unsatisfied. By tuning the electronic structures of materials, one can develop catalysts with enhanced activity. Here we synthesize a Pt-Au alloy with subnano size as cocatalyst on TiO₂ nanosheets for photocatalytic H₂ generation that shows an outstanding activity with a H₂ generation rate of 80.1 μmol h^-1 for at least 100 h. The activity is twice than the pure Pt cocatalyst, mainly because the optimized hydrogen adsorption energy on Pt cluster is tuned by Au atoms.