Accelerated kinetics of alkaline hydrogen evolution/oxidation reactions on dispersed ruthenium sites through N and S dual coordination

Descriptor-Driven Computational Design of Bifunctional Double-Atom Hydrogen Evolution and Oxidation Reaction Electrocatalysts for Rechargeable Hydrogen Gas Batteries

“…In terms of kinetics, the energy barrier of water activation (E a ) was investigated by conducting climbing image nudged elastic band (CI-NEB) calculations, which is generally considered as the kinetic rate-determining step that could affect the overall reaction rates. 29 As depicted in Figure 4b− 4e) and some other reported values. 25,29 For the MnFe-BN, the HOR is difficult to be achieved because of the high kinetic energy barrier of 0.96 eV (Figure 4f) for the water combination process.…”

“…29 As depicted in Figure 4b− 4e) and some other reported values. 25,29 For the MnFe-BN, the HOR is difficult to be achieved because of the high kinetic energy barrier of 0.96 eV (Figure 4f) for the water combination process. Therefore, the FeFe−BN is identified as the most promising HER/HOR catalyst with both excellent thermodynamic and kinetic activities in alkaline conditions.…”

“…This shows the obvious advantages of DACs and confirms the “double-atom active sites effect” as expected. Moreover, the reversible HER/HOR is expected to be kinetically available on FeFe-BN, CoCo-BN, and CoFe-BN with transition reaction barriers for the H 2 O dissociation of 0.55, 0.57, and 0.72 eV (Figure b–d), respectively, which are lower than that on the Pt(111) surface of 0.82 eV (Figure e) and some other reported values. , For the MnFe-BN, the HOR is difficult to be achieved because of the high kinetic energy barrier of 0.96 eV (Figure f) for the water combination process. Therefore, the FeFe–BN is identified as the most promising HER/HOR catalyst with both excellent thermodynamic and kinetic activities in alkaline conditions.…”

“…In terms of kinetics, the energy barrier of water activation ( E a ) was investigated by conducting climbing image nudged elastic band (CI-NEB) calculations, which is generally considered as the kinetic rate-determining step that could affect the overall reaction rates . As depicted in Figure b–f, a transition state (TS) was identified during the water activation step, which linked the initial state of the adsorbed water molecule (H 2 O*, IS) and the final state of coadsorbed H* and OH* (H* + OH*, FS).…”

Electrocatalytic Hydrogen Oxidation in Alkaline Media: From Mechanistic Insights to Catalyst Design

“…Efforts undertaken to date to design alkaline HOR catalysts can be roughly divided into three categories: (1) precise control of particle size, morphology, phase, or substrate composition to boost the activity of PGMs (Pt, Ru, Pd, Ir, etc . ); − (2) alloyed structure with less PGMs to simultaneously achieve better catalytic performance; − (3) developing PGM-free catalysts, which mainly focus on nickel-based ones. , However, the relatively strong adsorption of H on PGMs, PGM alloys, and Ni-based catalysts impedes the reversible H adsorption/desorption during the HOR process, engendering obstacles to reaction kinetics . It has been experimentally verified that H adsorption has a direct regulatory effect on HOR activity.…”