A study on rationally designed GaN:ZnO/NiSe2 composite for photocatalytic hydrogen production under artificial as well as natural solar light

Abstract

This study demonstrates the effective synthesis of octahedral shaped GaN:ZnO microparticles using NH₄Cl as nitrogen source and cubic NiSe₂ nanoparticles utilizing hydrothermal method. Then the GaN:ZnO particles were readily combined with NiSe₂ nanoparticles, leading to the formation of a Schottky barrier at the GaN:ZnO and NiSe₂ interface. The physicochemical and optical properties of the prepared compounds were analysed using XRD, SEM, HR-TEM, XPS, and UV–Vis characterization techniques. The metallic nature and suitable work function of NiSe₂ accelerated the activity of GaN:ZnO. The effect of different weight percentages of NiSe₂ on the GaN:ZnO surface has been investigated. Under the optimal conditions, the photocatalyst achieved a remarkable H₂ evolution rate of 26,400 μmol h⁻¹.g⁻¹_cat. The enhanced hydrogen evolution rate is attributed to the combined effects of NiSe₂ on GaN:ZnO. As the wt % of NiSe₂ changes, the photocatalytic activity closely aligns with the light penetration effect. Moreover, beyond evaluating the catalytic activity, this study delves into activity under natural sunlight, and reusability over five cycles shows that it retains 88 % of its original performance alongside conversion efficiency of solar-to-hydrogen is also calculated.