# Direct Z-Scheme M2X/BiOY (M = Ag, Au; X = S, Se; Y = Cl, Br, I) Heterojunctions for Solar-Driven Photocatalytic Water Splitting Applications: A First-Principles Investigation

## TL;DR

This paper predicts new two-dimensional materials that could efficiently split water using sunlight, based on theoretical calculations.

## Contribution

The study proposes novel M2X/BiOY heterojunctions as efficient Z-scheme photocatalysts for solar water splitting through first-principles calculations.

## Key findings

- M2X/BiOY heterojunctions show staggered band alignments and suitable band edges for water splitting.
- These materials exhibit extended solar absorption in visible and near-infrared regions.
- Interfacial electric fields enhance carrier separation and redox overpotentials.

## Abstract

Two-dimensional direct Z-scheme photocatalysts have emerged as highly promising photocatalysts for solar-driven water splitting owing to their effective separation of photogenerated carriers and strong redox abilities. This study focuses on the theoretical prediction of promising Z-scheme photocatalysts for solar-driven water splitting based on M2X/BiOY (M = Ag, Au; X = S, Se; Y = Cl, Br, I) heterojunctions using first-principles calculations. All M2X/BiOY heterojunctions possess staggered band alignments, Z-scheme carrier migration, and suitable band edges for overall water splitting. Optical absorption spectra indicate that these heterojunctions exhibit significantly extended solar absorption in the visible and near-infrared regions. Moreover, the interfacial built-in electric fields of (0.46–0.72 V/Å) point from M2X to BiOY, promote photogenerated carrier separation, and enhance redox overpotentials, thereby improving photocatalytic performance. These results suggest that M2X/BiOY heterojunctions are promising Z-scheme photocatalysts for solar-driven water splitting and are expected to be experimentally prepared and realized in the near future.