2D/1D Zn0.7Cd0.3S p-n heterogeneous junction enhanced with NiWO4 for efficient photocatalytic hydrogen evolution

Abstract

Bimetallic solid solutions have attracted much attention in the field of photocatalysis due to their excellent photocatalytic properties. Here, Zn0.7Cd0.3S solid solution with two morphologies was prepared by typical solvent-thermal method. The co-existence of 1D rod-like Zn0.7Cd0.3S and 2D sheet-like Zn0.7Cd0.3S can be found in SEM and TEM diagrams. This special structure can provide a larger specific surface area for exposing more active sites and expanding optical contact surface, which is favorable for boosting photocatalytic water-splitting reaction. In addition, a p-n junction formed by the interface contact between NiWO4 and Zn0.7Cd0.3S effectively promotes the transfer of interfacial charges through the built-in electric field, and thus recombination of the electron-hole pairs is greatly inhibited. The highest photocatalytic H2 production rate in the Na2S/Na2SO3 system is 15.95 mmol h−1 g−1, which is 3.16 times higher than the bare Zn0.7Cd0.3S. Meanwhile, Mott-Schottky curves further confirmed the Zn0.7Cd0.3S and NiWO4 suitable conduction band and valence band position, forming a more effective thermodynamic charge transfer path. This work provides for the first time 2D/1D structure of Zn0.7Cd0.3S and highlights the more efficient photocatalytic hydrogen evolution performance of the p-n junction in Zn0.7Cd0.3S/NiWO4.