Fabrication of Low Adsorption Energy Ni–Mo Cluster Cocatalyst in Metal–Organic Frameworks for Visible Photocatalytic Hydrogen Evolution

• Published in: ACS applied materials & interfaces Vol. 8; no. 17; pp. 10808 - 10819
• Main Authors: Zhen, Wenlong, Gao, Haibo, Tian, Bin, Ma, Jiantai, Lu, Gongxuan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.05.2016
• Subjects: adsorption; alloy nanoparticles; alloys; catalysts; coordination polymers; energy; fluorescence; Gibbs free energy; hydrogen; hydrogen production; lighting; nickel; photocatalysis; solvents; low adsorption energy; NiMo@MIL-101; density functional theory; apparent quantum efficiency; visible photocatalytic hydrogen generation
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.5b12524

An effective cocatalyst is crucial for enhancing the visible photocatalytic performance of the hydrogen generation reaction. By using density-functional theory (DFT) and frontier molecular orbital (FMO) theory calculation analysis, the hydrogen adsorption free energy (ΔG H) of Ni–Mo alloy (458 kJ·mol–1) is found to be lower than that of Ni itself (537 kJ·mol–1). Inspired by these results, the novel, highly efficient cocatalyst NiMo@MIL-101 for photocatalysis of the hydrogen evolution reaction (HER) was fabricated using the double solvents method (DSM). In contrast with Ni@MIL-101 and Mo@MIL-101, NiMo@MIL-101 exhibited an excellent photocatalytic performance (740.2 μmol·h–1 for HER), stability, and high apparent quantum efficiency (75.7%) under 520 nm illumination at pH 7. The NiMo@MIL-101 catalyst also showed a higher transient photocurrent, lower overpotential (−0.51 V), and longer fluorescence lifetime (1.57 ns). The results uncover the dependence of the photocatalytic activity of HER on the ΔG H of Ni–Mo (MoNi4) alloy nanoclusters, i.e., lower ΔG H corresponding to higher HER activity for the first time. The NiMo@MIL-101 catalyst could be a promising candidate to replace precious-metal catalysts of the HER.