Identifying the Transfer Kinetics of Adsorbed Hydroxyl as a Descriptor of Alkaline Hydrogen Evolution Reaction

Abstract

The key descriptor that dominates the kinetics of the alkaline hydrogen evolution reaction (HER) has not yet been unequivocally identified. Herein, we focus on the adsorbed hydroxyl (OHad) transfer process (OHad + e− ⇄ OH−) and reveal its crucial role in promoting the overall kinetics of alkaline HER based on Ni/Co‐modified MoSe2 model catalysts (Ni‐MoSe2 and Co‐MoSe2) that feature almost identical water dissociation and hydrogen adsorption energies, but evidently different activity trends in alkaline (Ni‐MoSe2 ≫ Co‐MoSe2) and acidic (Co‐MoSe2 ≥ Ni‐MoSe2) media. Experimental and theoretical calculation results demonstrate that tailoring MoSe2 with Ni not only optimizes the hydroxyl adsorption, but also promotes the desorption of OH− and the electron‐involved conversion of OHad to OH−, all of which synergistically accelerate the kinetics of OHad + e− ⇄ OH− and thereby the overall kinetics of the alkaline HER.

Competitive Adsorption: Reducing the Poisoning Effect of Adsorbed Hydroxyl on Ru Single‐Atom Site with SnO2for Efficient Hydrogen Evolution

“…As displayed in Figure S29b, the Ru/C owned a more negative potential than that of Ru SAs‐SnO 2 /C in 1.0 M KOH. The slightly negative surface charge on the Ru SAs‐SnO 2 /C indicated that the strong adsorption strength between adsorption site and OH ad hindered the OH ad transfer process (OH ad +e − OH − ) [3] . The above tests were performed to evaluate their ability for OH‐adsorption under positive potential and without external voltage.…”

“…However, the influence of adsorbed hydroxyl (OH ad ) on active sites has been paid less attention. Principally, the Volmer step (H 2 O+e − H ad +OH − ) can be divided into H 2 O H ad +OH ad and OH ad +e − OH − [3] . (H ad : the adsorbed hydrogen atom).…”

Interfaces Decrease the Alkaline Hydrogen-Evolution Kinetics Energy Barrier on NiCoP/Ti3C2Tx MXene

“…1,2 The hydrogen evolution reaction (HER) kinetics in alkaline medium is much slower than that in acid solution, due to more complex steps of adsorption and dissociation of water in an environment full of hydroxyl (OH − ) disturbance. 3,4 According to the Arrhenius equation, we can deduce the kinetics energy barrier (E a ) by designing suitable catalysts or increase the reaction temperature (T) to boost the alkaline HER kinetics. Few-layered Ti 3 C 2 T x MXenes have been confirmed as ideal substrates to disperse and load catalytically active material, as they show the advantages of better electron conductivity and anti-interference of hydroxyls by their surface electronegativity.…”

“…Water electrolysis in alkaline medium has been regarded as a promising approach to achieve large-scale renewable hydrogen production. , The hydrogen evolution reaction (HER) kinetics in alkaline medium is much slower than that in acid solution, due to more complex steps of adsorption and dissociation of water in an environment full of hydroxyl (OH – ) disturbance. , According to the Arrhenius equation, we can deduce the kinetics energy barrier ( E a ) by designing suitable catalysts or increase the reaction temperature ( T ) to boost the alkaline HER kinetics. Few-layered Ti 3 C 2 T x MXenes have been confirmed as ideal substrates to disperse and load catalytically active material, as they show the advantages of better electron conductivity and anti-interference of hydroxyls by their surface electronegativity. − Transition metal phosphides (TMPs) have been thought as one kind of promising alternatives for noble metal platinum in alkaline HER catalysis, , because their diversity (rich stoichiometric components, easy doping by heteroatoms, controllable phase transitions, etc .)…”

Interfacial engineering in amorphous/crystalline heterogeneous nanostructures as a highly effective battery-type electrode for hybrid supercapacitors

“…The rst-principles calculations show that amorphous phosphate and oxides can produce a large number of dangling bonds on the surfaces of the material, making them promising candidates for electrocatalysis and power storage. 16,17 Meanwhile, the amorphous phase reduces the interfacial transport barrier and increases charge storage sites to dredge carriers at the interface. Zhang et al recommended amorphous Co-Ni pyrophosphates as a battery-type electrode, which proved to possess excellent specic capacity and high cycling stability.…”