Efficient, Full Spectrum-Driven H₂ Evolution Z-Scheme Co₂P/CdS Photocatalysts with Co–S Bonds

Abstract

Exploring high-efficiency, low-cost, and stable photocatalysts that enable full solar spectrum including UV, visible, and near-infrared (NIR) light utilization for photocatalytic hydrogen generation still faces huge challenge. Herein, a Co₂P/CdS Z-scheme photocatalyst without a noble metal is rationally fabricated to achieve ultrabroad UV-vis-NIR harvesting. Compared to Pt/CdS, CdS, and Co₂P, the optimized Co₂P/CdS exhibits much more outstanding performance with the H₂ generation rates of 262.16, 66.98, and 3.93 mmol/g/h under solar, visible (780 nm > λ > 420 nm), and NIR (λ > 780 nm) light, respectively. Particularly, 10% Co₂P/CdS displays a prominent apparent quantum efficiency value of 2.26% at 700 nm. The Z-scheme transform route can effectively enhance the separation of charge carriers in Co₂P/CdS for UV-vis-driven HER, as confirmed by photoluminescence and photoelectrochemical measurements. More importantly, the Co-S bonds at the interface demonstrated by Fourier transform infrared, Raman (mapping), and X-ray photoelectron spectroscopy and density functional theory calculations can act as a "bridge" for charge transfer, thereby enhancing the full spectrum-driven H₂ evolution. To the best of our knowledge, this is a rare research on full spectrum-driven photocatalytic HER without a noble metal.