Plasmonic Ni 3 N Cocatalyst Boosting Directional Charge Transfer and Separation toward Synergistic Photocatalytic-Photothermal Performance of Hydrogen and Benzaldehyde Production as Well as Bacterial Inactivation.

Charge separation and transfer are the dominating factors in achieving high activity of solar energy-based photocatalysis. Here, a plasmonic transition metal nitride, Ni 3 N, nanosheet was fabricated and employed as an efficient cocatalyst to couple with Cd 0.9 Zn 0.1 S (CZS) solid solution via a self-assembly method to form a novel Ni 3 N/CZS heterojunction with an intimate interface. On one hand, localized surface plasmon resonance of the Ni 3 N nanosheets endowed the fabricated Ni 3 N/CZS composite with a wide-spectrum light absorption capacity, even to the near-infrared range. On the other hand, Ni 3 N as a cocatalyst can not only effectively induce the directional electron transfer from CZS to Ni 3 N active sites but also enhance the surface charge separation efficiency of the Ni 3 N/CZS heterojunction by 4.1 times compared to that of pure CZS. Plasmonic Ni 3 N also provided a photothermal effect to enhance the surface temperature of the composite for boosting the catalytic reaction kinetics. As a result, under visible light irradiation, the optimal Ni 3 N/CZS composite exhibited simultaneous H 2 generation and benzaldehyde formation rates of 35.08 and 16.44 mmol g -1 h -1 , which were 9.4 and 5.9 times those of CZS, respectively; and the composite also demonstrated a strong antibacterial ability with a sterilization rate of 99.7% toward Escherichia coli . Besides that, under NIR light, plasmonic Ni 3 N offered extra hot electrons that can transfer back to CZS to take part in the photocatalytic reaction, leading to the Ni 3 N/CZS composite still having a high H 2 production of 179.6 μmol g -1 h -1 . This work focuses on developing and applying novel plasmonic cocatalysts in photocatalysis for achieving adjustable electron transfer and fast charge separation for extensive practical application.