Novel dual co-catalysts decorated Au@HCS@PdS hybrids with spatially separated charge carriers and enhanced photocatalytic hydrogen evolution activity

Efficient charge separation and lower apparent activation energy of water splitting reaction remain the effective solutions to enhance the photocatalytic hydrogen performance. We design and fabricate novel Au@HCS@PdS hierarchical architectures with spatially separated oxidative and reductive co-catalysts by in-situ chemical process for hydrogen production. With the introduction of Au and PdS co-catalysts, photo-induced electron-hole pairs are not only effectively separated, but also reduce the activation energy and accelerate the surface oxidation-reduction reactions. As expected, Au@HCS@PdS hybrids exhibit remarkable H-2 evolution rate (16.35 mmol h(-1) g(-1)), which is about 112 times of hollow CdS photocatalyst and the average apparent quantum efficiency (AQE) reached 41% at 420 nm within 4h. Based on the techniques of surface photovoltage spectroscopy (SPV), electron spin resonance (ESR), linear sweep voltammetry (LSV) and the apparent activation energies which are calculated by an Arrhenius equation, the processes of electrons and holes transfer paths are proposed. The research will deepen our understanding over the surface reaction and provide new insights on the design of photocatalysts with multiple architectures and spatial charge separation.