Vanadium tetrasulfide as an earth-abundant and noble-metal-free cocatalyst for a solar-to-hydrogen conversion reaction

Abstract

Designing non-precious metal cocatalysts with high surface area that facilitate interfacial charge separation is a significant challenge in solar-to-hydrogen energy conversion reactions. Herein, we report a heterostructured photocatalytic system consisting of highly dispersed oxygen-doped VS₄ nanoparticles on a one-dimensional network of cadmium sulfide nanorods. Structural and morphological investigations revealed that the VS₄ nanoparticles created Schottky heterojunctions for efficient charge transfer and provided abundant catalytic active sites. Additionally, the higher work function of VS₄ enabled a superior transfer of photoinduced charge carriers from CdS to all accessible VS₄ NPs, realizing excellent visible photocatalytic hydrogen evolution activity. As a result, the obtained CdS/VS₄ heterostructures exhibited an outstanding catalytic activity of 5846 μmol g⁻¹ h⁻¹, which was five times higher than that of pure CdS nanorods. Moreover, the optimized CdS/VS₄ photocatalytic system with an ultralow amount of the VS₄ cocatalyst outperformed the Pt and MoS₂ cocatalysts in the CdS-Pt and CdS-MoS₂ photocatalytic systems, respectively. This study demonstrates a breakthrough in the exploration and development of non-noble-metal-based cocatalysts for efficient charge separation in solar-to-fuel conversion reactions.