Strong electronic coupling in Mn0.5Cd0.5S/Nb2CTX ohmic junctions enhances photocatalytic hydrogen evolution

Abstract

The strong electron coupling and intrinsic electric field within composite photocatalysts can enhance the transport efficiency of photo-generated charges during photocatalytic hydrogen evolution. This study successfully constructed Mn_0.5Cd_0.5S/Nb₂CT_X ohmic junctions by loading Mn_0.5Cd_0.5S nanoparticles onto Nb₂CT_X, thereby enhancing the photocatalyst's hydrogen evolution performance. Mn_0.5Cd_0.5S/Nb₂CT_X forms a close interface contact, providing a proficient conductive conduit for electron migration throughout the progression of photocatalytic hydrogen generation. XPS characterization and density functional theory analyses indicate a pronounced robust electronic interaction at the Mn_0.5Cd_0.5S/Nb₂CT_X interface. This enhances the local electron density within Nb₂CT_X, thus promoting the total photocatalytic performance in H₂ evolution. The Mn_0.5Cd_0.5S/15%Nb₂CT_X composite catalyst displays remarkable photocatalytic hydrogen generation performance up to 25 mmol (g⁻¹ h⁻¹), coupled with an observed apparent quantum yield (AQY) as high as 2.28% under irradiation of 450 nm. This study shows a novel strategy to improve photocatalysis-driven hydrogen generation by constructing a charge-based coupling where an ohmic junction meets a catalyst supported on MXene materials.