Z-Scheme heterostructures of 2D SnC/Sc2CCl2 for overall water splitting with strong redox potential under visible light

Abstract

The two-dimensional (2D) Z-scheme system is an effective approach for hydrogen production via photocatalytic water splitting (PWS). This study established a 2D van der Waals (vdW) SnC/Sc₂CCl₂ heterojunction for PWS. The electronic and optical properties of the designed heterojunction were determined using first-principles methods, showing that the heterojunction, acting as a Z-scheme photocatalyst (ZSP), formed an induced internal electric field to achieve effective electron–hole separation. The strong redox ability (∼1.5 eV) and moderate energy barrier of the SnC/Sc₂CCl₂ heterojunction further enabled efficient PWS. Moreover, the PWS process benefited from the heterojunction's favorable absorption coefficient (10⁵ cm⁻¹) and solar-to-hydrogen conversion efficiency (21.36%) under visible light. The proposed Z-scheme SnC/Sc₂CCl₂ heterojunction is a promising candidate for photocatalytic overall water splitting (POWS) across a pH range of 0–14.