Interfacial engineering of an S-scheme Ni–Co PBAs/Borophene heterojunction: electronic structure modulation and enhanced photocatalytic H2 production

The simultaneous management of charge separation and surface reaction energetics remains a pivotal challenge in the development of efficient photocatalysts for hydrogen production. Herein, we report a dual‑functional interfacial engineering strategy by constructing an S‑scheme heterojunction between nickel‑cobalt Prussian blue analogues (Ni–Co PBAs) and metallic Borophene (Bp). The optimized Ni–Co PBAs/Bp composite achieves an exceptional hydrogen evolution rate of 56.04 mmol g −1 over 5 h in an Eosin Y‑sensitized system under visible light, surpassing its individual components by factors of 29 and 4.4, respectively. Integrated in situ spectroscopic and DFT analyses unveil a synergistic mechanism: Bp not only serves as a charge‑transfer mediator to enable efficient S‑scheme electron flow driven by a built‑in electric field, but also acts as an electronic modulator to upshift the d‑band center of Ni/Co sites, thereby optimizing hydrogen adsorption free energy. This work provides a concrete blueprint for developing high‑performance photocatalysts via co‑optimizing macroscopic charge dynamics and atomic‑scale site reactivity for solar fuel production.