Crystal-Phase Engineering of ZrS2/γ-BC6N Heterostructures for Enhanced Type-II Photocatalytic Water Splitting

Abstract

The rational design of van der Waals heterostructures through crystal-phase engineering offers a promising yet underexplored avenue for developing highefficiency photocatalysts. Moving beyond the conventional ZrS 2 /h-BN system, this study introduces a dual-strategy of phase transition (from h-BN to γ-BN) and controlled carbon doping to dramatically enhance solar-driven water splitting. The calculations reveal that the optimized ZrS 2 /γ-BC 6 N heterostructure possesses an ideal indirect bandgap (2.30 eV) and a type-II band alignment, which synergistically promotes the spatial separation of photogenerated charge carriers. Its band edges fully span the water redox potentials from neutral to alkaline conditions, thermodynamically enabling overall water splitting. Remarkably, this crystal-phase-modulated heterostructure exhibits pronounced improvements in key functional properties: a visible-light absorption coefficient as high as 4.10 × 10 5 cm -1 , a projected solar-to-hydrogen efficiency of 15.54%, and a power conversion efficiency of 10.50%, outperforming all comparable configurations in the series. These findings not only confirm the exceptional potential of the ZrS 2 /γ-BC 6 N heterostructure but also establish