Plasmon-Induced and Multichannel Electron Transfer-Improved Photocatalytic Hydrogen Production by CdS–Au–Pt Heterostructure

Light-driven charge separation efficiency has prime importance in semiconductor-assisted water splitting reactions for dihydrogen production. A profound electron(e – )-hole(h + ) separation can be achieved by a multicomponent hybrid and with the rapid hole-scavenging mechanism of the sacrificial reagent. In this context, a Pt/Au/CdS hetero-nanostructure has been synthesized and evaluated for photocatalytic hydrogen production with a sulfide shuttle as the sacrificial agent under λ > 300 nm of illumination. Hexagonal-cubic core–shell CdS nanostructures with dendrite architecture were prepared by a facile hydrothermal technique and metallic Au/Pt was impregnated with the photodeposition method. The photodeposition strategy facilitates uniform dispersion of metallic particles on the CdS surface, wherein each component has close contact with others. The plasmonic gold nanoparticles (Au NPs) in the hybrid nanostructure amplify the light-harvesting ability due to its pronounced surface plasmon resonance and also provide multiple “hot electron” injection channels. These electron transfer channels, i.e., Au to CdS, CdS to Pt, and Au to Pt, enhance the cocatalyst effect of Pt. Pt 0.72 /Au 0.28 /CdS exhibited the highest H 2 production of 15 mmol·h –1 ·g –1 with an apparent quantum efficiency (AQE) of 4.20% (λ = 420 nm) using aqueous Na 2 SO 3 –Na 2 S solution as the sacrificial agent. Herein, sulfide shuttles vitalized the hydrogen production efficiency by effectively scavenging the generated hole and its intrinsic photolytic mechanism also provided molecular hydrogen. The present work demonstrated a promising efficiency of multichannel electron transfer pathways in amelioration of hydrogen production. Simultaneously, the dual advantages of the Na 2 SO 3 –Na 2 S shuttle offer a unique opportunity for application of sulfide-containing wastewater as the sacrificial agent in a photocatalytic hydrogen production framework.