Synthesis of NiS2/polyvinylpyrrolidone/(CuIn)0·2Zn1·6S2 type II heterojunction photocatalysts for high-efficiency photocatalytic hydrogen production under visible light

Abstract

A robust NiS 2 /polyvinylpyrrolidone/(CuIn) 0·2 Zn 1·6 S 2 (NiS 2 /PVP/CIZS) photocatalyst was successfully synthesized through a sequential hydrothermal treatment. Firstly, the addition of PVP reduces the size of CIZS nanoparticles, resulting in appearing surface effect, and hence an improvement of chemical activity. Moreover, the small size of PVP/CIZS possesses a shorten transfer distance of photo-induced carriers. The photocatalytic H 2 evolution rate of 0.8 g PVP/CIZS elevates to 3112.7 μmol/g/h under visible light. After coupling with NiS 2 , the light absorption range and separation efficiency of photo-induced carriers for NiS 2 /PVP/CIZS composites have been elevated and the optimal photocatalytic hydrogen evolution rate of 15% NiS 2 /PVP/CIZS reaches up to 5369.4 μmol/g/h. There forms a type Ⅱ heterostructure on NiS 2 /PVP/CIZS, and the heterostructure facilitates to suppress the recombination and elevate the separation of photo generated electrons and holes. Therefore, the synergistic effect of size control and constructing a type Ⅱ heterostructure with NiS 2 on PVP/CIZS floriform photocatalyst helps to enhance photocatalytic performance of the composites. This work opens up a new way to prepare highly efficient photocatalysts under visible light. • NiS 2 /PVP/CIZS type II heterostructure was prepared by sequential hydrothermal method. • Adding PVP reduces the size of CIZS nanoparticles, resulting in a surface effect. • The optimal photocatalytic H 2 evolution rate of 15%NiS 2 /PVP/CIZS is 5369.4 μmol/g/h. • The synergism of surface effect and heterostructure elevates photocatalytic activity.