Synergizing the plasmonic and semiconductor properties of W18O49 for enhanced hydrogen evolution under broadband excitation

WO 2.72 , with its broad localized surface plasmon resonance (LSPR) response, holds significant potential for harvesting visible and near-infrared (NIR) solar radiation. However, due to its relatively low free electron density, its LSPR excitation intensity is inherently weaker compared to conventional plasmonic metals. In this study, we enhanced the LSPR response of WO 2.72 by coupling it with Au nanoparticles. Upon LSPR excitation, this hybrid structure enables efficient generation of hot electrons, which can be extracted by the surface-deposited CdS layer to drive hydrogen evolution reactions. Importantly, the incorporation of the CdS layer also leads to the formation of an S-scheme heterojunction between CdS and WO 2.72 due to their well-matched band structures. The formation of S-scheme heterojunction not only promotes more efficient UV-excited generation of photo electrons in WO 2.72 and CdS, but also prevents the mutual cancellation of hot electrons and photogenerated electrons due to interfacial band bending. This synergy ensures efficient generation and utilization of both hot electrons and photogenerated electrons, giving rise to an excellent hydrogen evolution rate of 165.5 ​mmol ​g −1 ​h −1 under the irradiation of the stimulated sunlight.