Controllable synthesis of large-scale SnSe2 nanosheet arrays and Te/SnSe2 vertical mixed-dimensional heterostructures for hydrogen evolution reaction

Abstract

As a characteristic two-dimensional (2D) layered material, SnSe2 exhibits promising applications in optoelectronic devices and energy catalysis due to its distinct physical and chemical properties. However, the controllable synthesis of large-scale SnSe2 nanostructures remains a significant challenge. In this study, we present an innovative growth strategy utilizing an FTO substrate as an in situ Sn source, enabling controlled synthesis of large-area (4 cm × 4 cm) SnSe2 nanosheet arrays. One-dimensional (1D) Te/two-dimensional (2D) SnSe2 vertical mixed-dimensional heterostructures were further fabricated. The Te/SnSe2 vertical heterostructures demonstrate significantly enhanced hydrogen evolution reaction performance compared to individual Te and SnSe2 nanostructures, achieving an overpotential of 0.73 V at 10 mA/cm2 and a Tafel slope of 110.05 mV/dec in a 1 M KOH electrolyte. The first-principles calculation results reveal that interfacial charge redistribution at the heterojunction substantially lowers the water dissociation energy barrier while optimizing hydrogen adsorption free energy. This growth strategy establishes a viable pathway for fabricating large-area 1D/2D vertical heterojunctions, and the combined experimental and theoretical findings advance our fundamental understanding of their hydrogen evolution reaction mechanisms.