The Role of Phosphate Group in Doped Cobalt Molybdate: Improved Electrocatalytic Hydrogen Evolution Performance

He, Guanjie (2020) The Role of Phosphate Group in Doped Cobalt Molybdate: Improved Electrocatalytic Hydrogen Evolution Performance. Advanced Science . ISSN 2198-3844

Full content URL: https://doi.org/10.1002/advs.201903674

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The Role of Phosphate Group in Doped Cobalt Molybdate: Improved Electrocatalytic Hydrogen Evolution Performance
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Abstract

The hydrogen evolution reaction (HER) is a critical process in the electrolysis of water. Recently, much effort has been dedicated to developing low-cost, highly efficient and stable electrocatalysts. Transition metal phosphides are investigated intensively due to their high electronic conductivity and optimized absorption energy of intermediates in acid electrolytes. However, the low stability of metal phosphide materials in air and during electrocatalytic processes causes a decay of performance and hinders the discovery of specific active sites. The HER in alkaline media is more intricate, which requires further delicate design due to the Volmer steps. In this work, we develop phosphorus modified monoclinic β-CoMoO4 as a low-cost, efficient and stable HER electrocatalyst for the electrolysis of water in alkaline media. The optimized catalyst shows a small overpotential of 94 mV to reach a current density of 10 mA cm-2 for the HER with high stability in KOH electrolyte, and an overpotential of 197 mV to reach a current density of 100 mA cm-2. Combined computational and in-situ spectroscopic techniques show P is present as a surface phosphate ion; that electron holes localise on the surface ions and both (P-O1-) and Co3+-OH- are prospective surface active sites for the HER.

Keywords:hydrogen evolution, electrocatalyst, density functional theory, in-situ ATR-IR
Subjects:F Physical Sciences > F200 Materials Science
F Physical Sciences > F120 Inorganic Chemistry
Divisions:College of Science > School of Chemistry
ID Code:40801
Deposited On:21 May 2020 14:59

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