Photocatalytic Mechanism and Enhanced Hydrogen Evolution in Z‐Scheme PtS2/SiC van der Waals Heterojunction

Abstract

Addressing the pressing challenges of energy shortages and environmental pollution, solar‐driven hydrogen production offers a promising solution for clean energy. This study presents a novel PtS2/SiC van der Waals heterojunction designed using density functional theory. The heterojunction possesses an indirect bandgap of 1.33 eV and an interlayer electrostatic potential difference of 8.6 eV. The heterojunction efficiently facilitates the generation of photoexcited electrons and holes, driven by a work function difference of 1.439 eV, enabling the transfer of photogenerated carriers between the materials via a Z‐scheme mechanism. Electrons accumulate in the conduction band of SiC, while holes localize in the valence band of PtS2. This mechanism provides a high redox overpotential, which provides more energy for water splitting and spatially separates charge carriers, achieving high carrier mobility. At pH = 7 in the light, the free energy of the heterojunction is significantly reduced, demonstrating the ability to spontaneously decompose water to produce hydrogen. Additionally, within the visible light spectrum, the heterojunction reaches a peak light absorption coefficient of 3.6 × 10⁵ cm−1 at a wavelength of 387.5 nm, highlighting its exceptional potential as a photocatalytic material.