The Effect of Cu and Ga Doped ZnIn2S4 under Visible Light on the High Generation of H2 Production

Ikki Tateishi,Satoshi Kaneco,Mai Furukawa,Hideyuki Katsumata

doi:10.3390/chemengineering3040079

Abstract

A Cu+ and Ga3+ co-doped ZnIn2S4 photocatalyst (Zn(1−2x)(CuGa)xIn2S4) with controlled band gap was prepared via a simple one-step solvothermal method. Zn(1−2x)(CuGa)xIn2S4 acted as an efficient photocatalyst for H2 evolution under visible light irradiation (λ > 420 nm; 4500 µW/cm2). The effects of the (Cu and Ga)/Zn molar ratios of Zn(1−2x)(CuGa)xIn2S4 on the crystal structure (hexagonal structure), morphology (microsphere-like flower), optical property (light harvesting activity and charge hole separation ability), and photocatalytic activity have been investigated in detail. The maximum H2 evolution rate (1650 µmol·h−1·g−1) was achieved over Zn0.84(CuGa)0.13In2S4, showing a 3.3 times higher rate than that of untreated ZnIn2S4. The bandgap energy of Zn(1−2x)(CuGa)xIn2S4 decreased from 2.67 to 1.90 eV as the amount of doping Cu+ and Ga3+ increased.

Highlights

Global energy shortage and the environmental pollution associated with burning fossil fuels have stimulated people’s interest in clean and sustainable energy
We investigated photocatalytic activity, optical properties, and surface morphology of ZnIn2S4 simultaneously co-doped with Ga3+ and Cu+
The X-ray powder diffraction (XRD) pattern of ZnIn2S4 could be indexed as the hexagonal structure (JCPDS number 65-2023)

Summary

Introduction

Global energy shortage and the environmental pollution associated with burning fossil fuels have stimulated people’s interest in clean and sustainable energy. Specific requirements to improve the activity of the photocatalytic material include efficient light absorption, effective separation of photogenerated charge carriers, and better efficiency to the interface for direct release of hydrogen and/or oxygen from water [13,14,15]. The size of the band gap formed by the conduction band (CB) and the valence band of the semiconductor’s photocatalyst is the most important issue [16,17,18]. Sulfide photocatalysts are advantageous for visible light driven photocatalysts because they have narrow band gaps and negative valence bands, due to the S electron orbital, than oxide-based photocatalysts [22,23,24]

Methods

Results

Conclusion