Optimization of Schottky barrier height and LSPR effect by dual defect induced work function changes for efficient solar-driven hydrogen production

Photocatalytic water splitting for hydrogen evolution provides a desired approach for sustainable clean energy. However, increasing the effective electron density for proton reduction remains a huge challenge due to the fast charge recombination kinetic. Herein, we propose an efficient strategy, based on manipulating the Schottky barrier height (SBH) and localized surface plasmonic resonances (LSPR) effect of Co-MoO2-x via dual defect (Co doping and oxygen vacancies) induced work function change, to achieve higher electrons density in plasmonic CdS/Co-MoO2-x@C Schottky junction photocatalyst for the first time. Through varying the Co heteroatom doping and oxygen vacancies in our Co-MoO2-x@C cocatalyst, we show adjustable SBH at the interface and tunable photothermal effect in CdS/Co-MoO2-x@C, which leads to inhibited energetic electrons backflow in metallic Co-MoO2-x to improve the electron density. Moreover, optimized electronic structure gives rise to a zero-approaching Gibbs free energy for intermediate state, enabling CdS/Co-MoO2-x@C with promoted intrinsic H2 evolution kinetics. Furthermore, the extended light absorption and elevated reaction temperature stemming from strong LSPR effect of Co-MoO2-x contribute to the decrease of apparent activation energy from 13.824 to 6.579kJ/mol for H2 evolution. To this end, CdS/Co-MoO2-x@C-7 photocatalyst yields a full-spectrum driven photocatalytic H2 production rate of 89.95 mmol g−1h−1, surpassing most reported CdS-based photocatalyst. This study opens a new avenue toward construction of efficient broad-spectrum active photocatalyst.