Interfacial Structure of Water as a New Descriptor of the Hydrogen Evolution Reaction

Abstract

Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and activity is still yet to be established. Herein, using Pt and Pt–Ni nanoparticles we first demonstrate a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer changes from the proton acceptors to the donors with increasing pH. In the base, the reactivity of the interfacial water varied its structure, and the activation energies of water dissociation increased in the sequence: the dangling O−H bonds < the trihedrally coordinated water < the tetrahedrally coordinated water. Moreover, optimizing the adsorption of H and OH intermediates can re‐orientate the interfacial water molecules with their H atoms pointing towards the electrode surface, thereby enhancing the kinetics of HER. Our results clarified the dynamic role of the water structure at the electrode–electrolyte interface during HER and the design of highly efficient HER catalysts.

Engineering the Electronic Interaction between Metals and Carbon Supports for Oxygen/Hydrogen Electrocatalysis

“…116 Thus, the deposition of Ni(OH) 2 on Pt improve the slow kinetics under alkaline solutions. The importance of interfacial water structure is also verified by Xu et al and Sun et al 117,118 Moreover, Jia et al unified the HER/HOR kinetics with an adsorbed hydroxyl (OH ad )−water−alkali metal cation (AM + ) adducts. 119 These findings provide other paths for understanding reacting mechanisms and optimizing electrocatalytic performances.…”

Sulfate‐Functionalized RuFeOx as Highly Efficient Oxygen Evolution Reaction Electrocatalyst in Acid

“…The extensive band at 3000 to 3600 cm −1 was attributed to the OH stretching mode of the interfacial water. [ 27 ] This broad peak can be deconvoluted into three peaks, which are corresponding to the strongly bonded “ice‐like” water (strongly OH, ν(OH) s , ≈3200 cm −1 ), the medially bonded “liquid‐like” water (medially OH, ν(OH) w , ≈3400 cm −1 ), and the isolated non‐hydrogen‐bonded water (free OH, ν(OH) i , ≈3600 cm −1 ), respectively, [ 20b,28 ] and the deconvolution results are summarized in Table S2, Supporting Information. Compared with RuO 2 , the sulfate doped catalysts have a larger proportion of the medially bonded water.…”

Microstrain Engineered NixS2/PtNi Porous Nanowires for Boosting Hydrogen Evolution Activity

“…Thus, the NiS 2 /PtNi NWs, Ni 3 S 2 /PtNi NWs, and PtNi NWs follow Heyrovsky steps (39 mV dec −1 ) in alkaline solution, and Pt/C follows Volmer steps (118 mV dec −1 ). 29,30 These results indicate that the Ni x S 2 /PtNi interface heterostructures promote the HER kinetics of Ni x S 2 /PtNi NWs compared with PtNi NWs and Pt/ C. Among current state-of-art Pt-based and non-Pt-based catalysts reported elsewhere, NiS 2 /PtNi NWs shows the best HER activity (Table S1) in alkaline electrolyte. Then, the stability of NiS 2 /PtNi NWs was assesed using an accelerated LSV test in 0.1 M KOH.…”

“…The Tafel slopes of NiS 2 /PtNi NWs, Ni 3 S 2 /PtNi NWs, PtNi NWs, and Pt/C are 38, 54, 63, and 102 mV dec –1 in 0.1 M KOH, respectively. Thus, the NiS 2 /PtNi NWs, Ni 3 S 2 /PtNi NWs, and PtNi NWs follow Heyrovsky steps (39 mV dec –1 ) in alkaline solution, and Pt/C follows Volmer steps (118 mV dec –1 ). , These results indicate that the Ni x S 2 /PtNi interface heterostructures promote the HER kinetics of Ni x S 2 /PtNi NWs compared with PtNi NWs and Pt/C. Among current state-of-art Pt-based and non-Pt-based catalysts reported elsewhere, NiS 2 /PtNi NWs shows the best HER activity (Table S1) in alkaline electrolyte.…”