Doping β-CoMoO₄ Nanoplates with Phosphorus for Efficient Hydrogen Evolution Reaction in Alkaline Media

Abstract

Mass production of hydrogen by electrolysis of water largely hinges on the development of highly efficient and economical electrocatalysts for hydrogen evolution reaction (HER). Though having the merits of high earth abundance, easy availability, and tunable composition, transition-metal oxides are usually deemed as poor electrocatalysts for HER. Herein, we demonstrate that doping β-CoMoO 4 nanoplates with phosphorus can turn them into active electrocatalysts for HER. Theoretical calculation and experimental studies unravel that enhanced electrical conductivity and optimized hydrogen adsorption free energy are major causes for the improvement of intrinsic activity. As a result, only an overpotential of 138 mV is required to drive hydrogen evolving at a current density of 10 mA cm −2 in 1 M KOH for P-doped β-CoMoO 4 , which outstrips many recently reported transition-metal oxides and is just slightly inferior to commercial Pt/C. This work opens a new route to tune the HER performance of transition-metal oxides.

Phosphorus‐Functionalized Fe2VO4/Nitrogen‐Doped Carbon Mesoporous Nanowires with Exceptional Lithium Storage Performance

“…The formation energies ( E form ) of different doped systems were calculated to evaluate the stability of different doped models, where E form was calculated using Equation : …”

Tailoring Oxygen Vacancies in CoMoO4 for Superior Lithium Storage

“…CoMoO 4 draws great attention due to its variable oxidation states and unique d-electron configuration. [5] Compared with the individual cobalt oxide and molybdenum oxide, the electrochemical reactivity of the electrode material would be effectively promoted due to the synergistic effect between cobalt and molybdenum. [6,7] For example, Chen and co-workers reported the fabrication of CoMoO 4 /carbon cloth with a high specific capacity of 764 mA h g À 1 after 1000 cycles at 1200 mA g À 1 .…”

“…The conversion‐type anodes, including metal oxides, [2] metal sulfides, [3] and metal carbides, [4] have been demonstrated as promising anode candidates of LIBs, derived from their high theoretical capacity, rich structural chemistry, and high abundance. CoMoO 4 draws great attention due to its variable oxidation states and unique d‐electron configuration [5] . Compared with the individual cobalt oxide and molybdenum oxide, the electrochemical reactivity of the electrode material would be effectively promoted due to the synergistic effect between cobalt and molybdenum [6,7] .…”

Recent advances in transition metal-based electrocatalysts for alkaline hydrogen evolution

“…Mo-based materials are promising HER catalysts among which transition metal molybdates (MMoO 4 ) have been demonstrated as efficient electrocatalysts for alkaline HER due to their high activities and adjustable electronic structures by the synergy of Mo and M 54. Lately, Li and co-workers investigated the catalytic properties of P-doped β-CoMoO 4 prepared by a two-step strategy(Figure 7a) 53. The doped sample showed a better performance than β-CoMoO 4 and Co-Mo-O, with a small overpotential (η 10 = 138 mV) and a low Tafel slope (68.76 mV dec -1 )(Figure 7b and c).The density of states (DOS) of different samples indicated that the P doping narrowed the bandgap of β-CoMoO 4 from 2.09 eV to 1.87 eV, introduced more charge carriers and ameliorated the electrical conductivity (Figure 7d).…”