Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Abstract

Bifunctional hydrogen electrocatalysis (hydrogen‐oxidation and hydrogen‐evolution reactions) in alkaline solution is desirable but challenging. Among all available electrocatalysts, Ni‐based materials are the only non‐precious‐metal‐based candidates for alkaline hydrogen oxidation, but they generally suffer from low activity. Here, we demonstrate that properly alloying Ni with Mo could significantly promote its electrocatalytic performance. Ni4Mo alloy nanoparticles are prepared from the reduction of molybdate‐intercalated Ni(OH)2 nanosheets. The final product exhibits an apparent hydrogen‐oxidation activity exceeding that of the Pt benchmark and a record‐high mass‐specific kinetic current of 79 A g−1 at an overpotential of 50 mV. A superior hydrogen‐evolution performance is also measured in alkaline solution. These experimental data are rationalized by our theoretical simulations, which show that alloying Ni with Mo significantly weakens its hydrogen adsorption, improves the hydroxyl adsorption and decreases the reaction barrier for water formation.

Sequential self-reconstruction of localized Mo species in hierarchical carbon/Co–Mo oxide heterostructures for boosting alkaline hydrogen evolution kinetics and durability

“…3c). 27–29 In contrast, the weak Mo 6+ signals are detected from the Mo 3d spectrum of Co@NCNT/CoMo y O x , 30 suggesting that a large amount of Mo species is oxidized and dissolved into the electrolyte in the form of MoO 4 2− , 31 which is consistent with the mapping and EDS results. Besides, the Co 2p spectrum of Co@NCNT/CoMo y O x shows a slight increase in the peak area ratio of Co 3+ /Co 2+ as compared with that of pristine Co@NCNT/CoMoO x , which could be ascribed to the re-formation of cobalt oxides after the dissolution of MoO 4 2− in the CoMoO x matrix (Fig.…”

Catalyst overcoating engineering towards high-performance electrocatalysis

“…Typically, alloying with another metal (i.e. NiMo, 268,269 NiCu, 270 CoNiMo, 271 NiWCu 272 ), doping with a non-metal element (i.e. N, B), 273,274 strain engineering 275 and interfacial construction 276 have been validated to be available attempts for modulating the electronic structure of Ni and optimizing the binding interactions with surface intermediates.…”

Synergistic Electrocatalysts for Alkaline Hydrogen Oxidation and Evolution Reactions

“…Ni-based materials are listed with a specific focus due to their competitive activity to the Pt/C in alkaline, as widely reported in recent literature. [67][68][69] For PGM 1 /PGM 2 combination, Pt-Ru alloys are the most reported HOR catalysts in alkaline and are widely explored in both model systems and practical devices. [21,28,72,73] The appropriate HBE of Pt and oxophilic Ru provide superior HOR activity.…”

“…[40,83,84] The Gibbs free energy of H adsorption (ΔG Had ) on pure Ni was about -0.3 eV, which is slightly away from the thermoneutral state (ΔG Had = 0). [69] Alloying Ni with another metal (Ni/non-PGM) can not only modulating the H adsorption behavior on Ni but also introducing the synergistic sites for the adsorption of OH ad .…”

“…Copyright 2020, Springer Nature. f-h) Reproduced with permission [69]. Copyright 2021, John Wiley & Sons.…”