Capacitance effect of ZnIn2S4 with delicate morphology control on photocatalytic hydrogen evolution

Abstract

The capacitance effect of semiconductor photocatalysts for hydrogen production is significant; however, the intrinsic role of capacitance in relation to the morphologies of photocatalysts remains unclear. Herein, we designed three different morphologies of ZnIn₂S₄ semiconductor material—spherical, bulk, and rod-like—to determine their capacitance. In this study, the small capacitance characteristics of spherical ZnIn₂S₄ (0.363F/g) enabled photoelectrons to quickly transfer to the surface and participated in the photocatalytic hydrogen evolution reaction, leading to a photocatalytic activity of 159 μmol/h/g. When TiVAlC nanoparticle with M_n+1AX_n (MAX) nanostructure was employed as efficient co-catalyst, TiVAlC/ZnIn₂S₄-S achieved an increased activity of 285 μmol/h/g at 420 nm, which was 1.75 times that of TiVAlC/ZnIn₂S₄-B and 2.39 times that of TiVAlC/ZnIn₂S₄-R. This enhanced performance was attributed to the synergistic effect of the high-efficiency semiconductor photocatalyst ZnIn₂S₄-S with small capacitance and the superior conductivity of the Mxene material TiVAlC.