Molten‐Salt‐Mediated Synthesis of an Atomic Nickel Co‐catalyst on TiO2 for Improved Photocatalytic H2 Evolution

• Published in: Angewandte Chemie International Edition 2020-04, Vol.59 (18), p.7230-7234
• Main Authors: Xiao, Mu, Zhang, Lei, Luo, Bin, Lyu, Miaoqiang, Wang, Zhiliang, Huang, Hengming, Wang, Songcan, Du, Aijun, Wang, Lianzhou
• Format: Article
• Language: English
• Subjects: atomic co-catalysts; Bonding strength; Catalysts; Charge transfer; Chemical bonds; Chemical synthesis; Environmental effects; Evolution; Hydrogen evolution reactions; Molten salts; molten-salt method; Nanoparticles; Nickel; oxygen vacancies; Photocatalysis; Salts; Titanium dioxide; Water splitting
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202001148

Atomic co‐catalysts offer high potential to improve the photocatalytic performance, of which the preparation with earth‐abundant elements is challenging. Here, a new molten salt method (MSM) is designed to prepare atomic Ni co‐catalyst on widely studied TiO2 nanoparticles. The liquid environment and space confinement effect of the molten salt leads to atomic dispersion of Ni ions on TiO2, while the strong polarizing force provided by the molten salt promotes formation of strong Ni−O bonds. Interestingly, Ni atoms are found to facilitate the formation of oxygen vacancies (OV) on TiO2 during the MSM process, which benefits the charge transfer and hydrogen evolution reaction. The synergy of atomic Ni co‐catalyst and OV results in 4‐time increase in H2 evolution rate compared to that of the Ni co‐catalyst on TiO2 prepared by an impregnation method. This work provides a new strategy of controlling atomic co‐catalyst together with defects for efficient photocatalytic water splitting. Atomic nickel: A facile molten‐salt method is used to prepare an atomic Ni co‐catalyst on TiO2. This system has photocatalytic H2 evolution activity that is four times higher than that of Ni nanoparticles on TiO2.