Role of Oxidized Mo Species on the Active Surface of Ni–Mo Electrocatalysts for Hydrogen Evolution under Alkaline Conditions
Azofra Mesa, Luis
Emwas, Abdul-Hamid M.
KAUST DepartmentCatalysis for Energy Conversion (CatEC)
Centre for Research and Development, Saudi Arabian Basic Industries Corporation (SABIC), 4700 KAUST, Thuwal 23955-6900, Saudi Arabia
Chemical Science Program
KAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division
Online Publication Date2020-10-20
Print Publication Date2020-11-06
Permanent link to this recordhttp://hdl.handle.net/10754/665658
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AbstractA Ni–Mo composite functions as a promising non-noble metal electrocatalyst for the hydrogen evolution reaction (HER) in alkaline water. Despite its industrial relevance, the kinetic origin of the high catalytic activity remains under debate. The present report discusses a reaction mechanism of HER on Ni–Mo catalysts by combining experimental and theoretical studies. In contrast to a Ni catalyst, a Ni–Mo catalyst is insensitive to CO gas introduced during HER. In situ spectroscopic measurements including Raman spectroscopy and electron paramagnetic resonance (EPR) show that Mo3+ prevails during HER catalysis. Density functional theory (DFT) simulations corroborate the thermodynamic stability and HER activity of Mo3+-containing centers on Ni(111) at HER potentials. Notably, Ni is demonstrated to play no direct role as a catalytic site but to effectively disperse and activate the oxidized catalytic Mo species. The results illustrate how to improve the electrocatalytic activity for alkaline HER.
CitationBau, J. A., Kozlov, S. M., Azofra, L. M., Ould-Chikh, S., Emwas, A.-H., Idriss, H., … Takanabe, K. (2020). Role of Oxidized Mo Species on the Active Surface of Ni–Mo Electrocatalysts for Hydrogen Evolution under Alkaline Conditions. ACS Catalysis, 12858–12866. doi:10.1021/acscatal.0c02743
SponsorsThe research reported in this study was supported by the King Abdullah University of Science and Technology. The authors acknowledge the support of SABIC in funding this research. Computational resources were provided primarily by the KAUST Supercomputing Laboratory and the Shaheen II supercomputer. Computational work was also partially performed using resources of the National Supercomputing Centre, Singapore (https://www.nscc.sg).
PublisherAmerican Chemical Society (ACS)