Atomic-level charge separation boosting the photocatalytic hydrogen evolution

Abstract

The synergistic implementation of atomic-level charge separation strategies for bulk–surfaces is a meaningful study that fundamentally addresses the shortcomings of single materials. Here, we report for the first time the atomic-level engineering of atomic doping in combination with surface ion grafting, which can be coordinated to significantly facilitate photocatalytic H2 evolution. More impressively, the study systematically investigated the atomic doping effects of Fe, Co, Ni and Cu atoms, and analyzed the conditions for optimal doping with experimental and theoretical calculations. The doping of variable valence Cu atoms leads to the emergence of newly occupied electronic states at the Fermi energy level, which effectively improves the carrier separation. The X-ray absorption spectroscopy (XAS) results verified the precise coordination environments of the doped Cu atoms, as well as confirmed the solid grafting of Ni ions on the catalyst surface. Furthermore, the hydrogen production rate of 1.2 % Cu–Zn0.67Cd0.33S–0.5 wt% Ni reached 38.17 mmol/g/h, corresponding to an apparent quantum efficiency of 35.5 %, which is 82.8 times higher than that of pure ZCS. Besides, the H2 production rate can reached 118.73 mmol/g/h without cooling. Meanwhile, the synergistic strategy of manipulating the bulk and surface photo-charges of Zn0.67Cd0.33S also effectively enhances the photothermal effect and further improves its photocatalytic performance. This work provides different inspirations for bottom-up design of efficient photocatalysts to achieve synergistic facilitation strategies.