Accelerated Photogenerated Charge Separation Driven Synergistically by the Interfacial Electric Field and Work Function in Z-Scheme Zn-Ni₂P/G-C₃N₄ for Efficient Photocatalytic Hydrogen Evolution

Abstract

The design of green and low-cost Z-scheme heterojunctions with the interfacial electric field (IEF) is of prime importance to their photocatalytic hydrogenation performance and practical application. In this work, we construct a novel Z-scheme heterojunction photocatalyst comprised of Zn-Ni₂P/g-C₃N₄ nanosheets for hydrogen evolution reaction (HER). Experimental results and density functional theory calculations demonstrate that the construction of Z-scheme Zn-Ni₂P/g-C₃N₄ heterostructure not only promotes the generation of IEF directing from Zn-Ni₂P to g-C₃N₄, along with work function, accelerating the photogenerated charge separation in Zn-Ni₂P/g-C₃N₄, but also leads to the upshift of the p-band state density in Zn-Ni₂P/g-C₃N₄, favorable for the H* adsorption toward HER. The Zn-Ni₂P/g-C₃N₄ photocatalyst demonstrated excellent photocatalytic HER activity, with a hydrogen production rate of up to 1077 µmol g⁻¹ h⁻¹ and a stability of 49 h. Our findings provide a new method to enhance the separation of photogenerated charges. This improvement boosts the photocatalytic properties of solar-driven materials and devices.

Keywords

Z-scheme heterojunction / g-C₃N₄ / interfacial electric field / work function / hydrogen evolution

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