Probing the potential of Al2CO/SiC heterostructures for visible light-driven photocatalytic water splitting using first-principles strategies

Abstract

Photocatalytic water splitting is a sustainable and eco-friendly method for renewable energy production. The development of an efficient photocatalyst based on two-dimensional (2D) heterostructures with suitable band offsets is at the heart of relevant research activities. In this work, we predict a novel 2D heterostructure of Al₂CO and SiC based on first-principles calculations of the structural, electronic, optical, interfacial, and photocatalytic mechanisms. The results indicate that AB stacking of the interface is energetically more favorable with a direct band gap of 2.27 eV. The interface exhibits strong covalent interaction, straddling-type band alignment, and suitable redox potentials for water splitting. Owing to their exceptional stability, the findings based on the work function revealed an efficient charge transfer mechanism due to the internal electric field. Furthermore, the optical properties of the structure indicate strong light harvesting ability in visible and ultraviolet regions. The findings suggest that the proposed heterostructure offer suitable band edge positions for hydrogen and oxygen evolution reactions. The mechanisms of water splitting, hydrogen and oxygen production are examined to explore the prospects of overall water splitting. Three fundamental steps—Volmer, Heyrovsky, and Tafel—are investigated to study the hydrogen evolution reaction (HER) activity. The screening of whole reaction pathways for oxygen production exhibited low theoretical overpotential and enhanced catalytic efficiency. This study demonstrates that the Al₂CO/SiC heterostructure is a promising material for overall water splitting in various pH ranges under visible light irradiation.