Strain-driven electronic structure modulation in ZrO2/ZnIn2S4 S-scheme heterojunctions: a theoretical study of multiscale modelling

Abstract

Photocatalytic hydrogen generation via water splitting offers an environmentally benign route to obtain green and sustainable energy. However, limited photocatalytic efficiency arising from rapid electron–hole recombination remains a critical challenge in the catalysis process. S-scheme heterojunctions leverage interfacial internal electric fields (IEFs) to drive charge separation, as the photocatalytic performance can be effectively enhanced by modulating field intensity. In response to the pressing demand for solar-to-hydrogen (STH) conversion efficiency improvement, this study proposes a scalable strategy for industrial photocatalytic systems through hydrodynamic strain engineering of catalyst particles to design a physical stimulation strategy for improving the photocatalytic performance of the S-scheme heterojunction. By employing hydrocyclone-induced high-frequency periodic oscillatory loading, interfacial strain displacements of up to 0.6 Å were achieved in ZrO₂/ZnIn₂S₄ heterojunctions, as quantified through finite element analysis. Density functional theory calculations elucidate the strain-dependent electronic restructuring, revealing interlayer spacing as a critical determinant of interfacial charge density distribution. Vertical compressive strain was found to intensify interfacial electron coupling, significantly reinforcing the IEF. Consequently, the strain–electronic interaction establishes a structure–activity relationship where optimized strain states accelerate photogenerated carrier separation. This study proposes an industrially scalable strategy for photocatalytic hydrogen evolution, utilizing hydrocyclone-mediated particle strain engineering to amplify the carrier separation efficiency inherent in the S-scheme heterojunction.