# Photocatalytic CO2 Reduction Using Zinc Indium Sulfide Aggregated Nanostructures Fabricated under Four Anionic Conditions

## TL;DR

This study explores how different anionic precursors affect the photocatalytic performance of zinc indium sulfide in reducing CO2, finding that one combination significantly boosts CO production.

## Contribution

The study introduces a novel method to optimize ZIS photocatalysts by systematically varying anionic precursors to enhance CO2 reduction efficiency.

## Key findings

- ZIS synthesized with Zn(CH3CO2)2/In2(SO4)3 achieved the highest CO production yield of 134 μmol g−1h−1.
- More zinc and indium vacancy defects in ZIS-AceSO4 improve photocatalytic performance, confirmed by EDS analysis.
- Energy levels of VBM and CBM were determined, offering insights into band alignment for photocatalytic processes.

## Abstract

Zinc indihuhium sulfide (ZIS), among various semiconductor materials, shows considerable potential due to its simplicity, low cost, and environmental compatibility. However, the influence of precursor anions on ZIS properties remains unclear. In this study, we synthesized ZIS via a hydrothermal method using four different anionic precursors (ZnCl2/InCl3, Zn(NO3)2/In(NO3)3, Zn(CH3CO2)2/In(CH3CO2)3, and Zn(CH3CO2)2/In2(SO4)3), resulting in distinct morphologies and crystal structures. Our findings reveal that ZIS produced from Zn(CH3CO2)2/In2(SO4)3 (ZIS-AceSO4) exhibited the highest photocatalytic CO2 reduction efficiency, achieving a CO production yield of 134 μmol g−1h−1. This enhanced performance is attributed to the formation of more zinc and indium vacancy defects, as confirmed by EDS analysis. Additionally, we determined the energy levels of the valence band maximum (VBM) and the conduction band minimum (CBM) via UPS and absorption spectra, providing insights into the band alignment essential for photocatalytic processes. These findings not only deepen our understanding of the anionic precursor’s impact on ZIS properties but also offer new avenues for optimizing photocatalytic CO2 reduction, marking a significant advancement over previous studies.