Mo₂C-MXene/CdS Heterostructures as Visible-Light Photocatalysts with an Ultrahigh Hydrogen Production Rate

Here, we report a visible-light photocatalyst (Mo2C-MXene/CdS) with H2 production rate higher than that of state-of-the-art catalysts based on noble metals or other MXenes. The photocatalyst was constructed from Mo2C MXene, Cd(NO3)2·4H2O, and thiourea with ethylenediamine, which has an acanthosphere structure with Mo2C two-dimensional (2D) sheets covered by wurtzite CdS nanocrystals. From theoretical calculation, Mo sites in the Mo2C-MXene/CdS(110) heterostructure provide an efficient reaction site for the hydrogen evolution reaction (ΔGH* = −0.18 eV). The electronic structures demonstrate that this heterostructure has favorable band gap and band edge position for water splitting. In experimental measurements, the photocatalyst shows a H2 production rate of 17 964 μmol g–1 h–1. The H2 production is ca. 20% higher than the previously reported value of Ti3C2 MXene catalysts and ca. 11% higher than that of noble-metal catalysts. Therefore, Mo2C-MXene/CdS heterostructure is a promising catalyst with ultrahigh performance to replace noble-metal catalysts.