Nickel phosphonate-derived Ni2P@N-doped carbon co-catalyst with built-in electron-bridge for boosting photocatalytic hydrogen evolution

• Published in: Inorganic chemistry frontiers 2022-05, Vol.9 (9), p.1964-1972
• Main Authors: Li-Jiao, Gao, Xin-Lian, Song, Jin-Tao, Ren, Zhong-Yong, Yuan
• Format: Article
• Language: English
• Subjects: Acceleration; Carbon; Catalysts; Charge transfer; Hydrogen evolution; Hydrogen production; Hydrogen-based energy; Inorganic chemistry; Nickel; Nitrogen; Noble metals; Phosphides; Phosphonates; Photocatalysis; Photocatalysts; Pyrolysis; Reaction kinetics; Solar energy conversion; Surface reactions; Transition metals
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/d2qi00064d

To construct photocatalytic systems that can efficiently convert solar energy to hydrogen energy, numerous studies have been focused on transition metal phosphide (TMP) co-catalysts, which display low overpotential and cost less than noble metals. However, as co-catalysts, the performance of pure TMPs is not satisfactory in photocatalytic H2 evolution, especially with regard to the acceleration of surface reaction kinetics and charge transfer through interfaces in the photocatalyst system. Herein, a nitrogen-doped carbon shell-coated nickel phosphide (Ni2P@CN) co-catalyst, which was fabricated via a one-step pyrolysis strategy with nickel phosphonate as the precursor and no extra P sources added, was composited with Cd0.5Zn0.5S (CZS). The surface reaction of the CZS/Ni2P@CN composite in photocatalytic H2 production was effectively accelerated owing to the abundant surface active sites afforded by the Ni2P@CN co-catalyst. Moreover, a series of experiments have demonstrated that the nitrogen-doped carbon shell (CN) encapsulates Ni2P and acts as a “built-in electron bridge” that provides a fast charge transfer channel from Cd0.5Zn0.5S to Ni2P. As a result of the unique interfaces and structure among Ni2P, CN and Cd0.5Zn0.5S, the CZS/Ni2P@CN-5% possesses an excellent photocatalytic H2 evolution rate (∼28.53 mmol h−1 g−1), which is up to 2.31 times as high as that of pristine Cd0.5Zn0.5S. This work brings a novel route to design marvellous co-catalysts in composite photocatalyst systems for boosting photocatalytic H2 production.