Interfacial Water Enrichment and Reorientation on Pt/C Catalysts Induced by Metal Oxides Participation for Boosting the Hydrogen Evolution Reaction

Abstract

State-of-the-art hydrogen evolution reaction (HER) catalysts have been Ptor Pt-based alloys so far due to their extremely low onset potential; however, their HER kinetics become worse under strong cathodic polarization. Herein, we take commercial Pt/ C decorated with a small amount of metal oxides (MO x -Pt/C) as model catalysts to improve the HER kinetics at a wide cathodic potential range in alkaline conditions. The MO x -Pt/C catalysts markedly reduce the Tafel slope and overpotential under both small and large cathodic polarization. Multiscale simulations reveal that the metal oxides can cause a so-called local electric field enhancement and induce interfacial water enrichment and reorientation. It accelerates the diffusion of hydrated K + and facilitates the activation of interfacial water, which boosts the Volmer step to match the fast H 2 evolution especially under strong potential polarization. Our work discloses important clues about how multiple components play a role in HER electrocatalysis.

Hierarchically Heterostructured Ni(OH)2/Fe–Ni2P Nanoarray: A Synergistic Electrocatalyst for Accelerating Alkaline Hydrogen Evolution

“…35−37 In the meantime, the transferred electrons are enriched on the Fe−Ni 2 P terminal, promoting its H* capture for achieving high-efficient hydrogen evolution. 38,39 The two components complement each other in advantages and synergistically enhance the alkaline HER process, as schematically depicted in Figure 4a and S5) and the corresponding ECSA-normalized current density (j ECSA ) of −0.56 mA cm −2 at 120 mV (Figure 4c), demonstrating its enriching active site couples with superior intrinsic activity. The comparison of turnover frequency (TOF) also confirms the above conclusion (Figure S6).…”

“…Thanks to the aforementioned heterointerface engineering, the Ni­(OH) 2 terminal exposes abundant electron-deficient surface, which is conducive to driving the nucleophilic attack toward molecular H 2 O and accelerating the rate-determined water dissociation step. − In the meantime, the transferred electrons are enriched on the Fe–Ni 2 P terminal, promoting its H* capture for achieving high-efficient hydrogen evolution. , The two components complement each other in advantages and synergistically enhance the alkaline HER process, as schematically depicted in Figure a. As a consequence, Ni­(OH) 2 /Fe–Ni 2 P possesses the highest double-layer capacitance ( C dl ) of 8.60 mF cm –2 (Figure b and S5) and the corresponding ECSA-normalized current density ( j ECSA ) of −0.56 mA cm –2 at 120 mV (Figure c), demonstrating its enriching active site couples with superior intrinsic activity.…”

Water Electrolysis toward Elevated Temperature: Advances, Challenges and Frontiers

“…In the case of PEMECs, the conducted ion is proton (H + ) transported through a polymer electrolyte membrane, while the deposited electrocatalysts promote the HER and OER on both sides, which are elucidated by eqs and . Currently, the most predominant disadvantage of operating PEMECs at lower temperature in the range of 25–100 °C is the relatively high cost induced by their great dependence on precious metals, such as Pt/Pd as HER electrocatalysts , and RuO 2 /IrO 2 as OER electrocatalysts. − Although a cost reduction is urgently needed, the inherently high gas purity caused by the dense membrane structures and exceptional dynamic response properties derived from compact configurations suggest great potential for practical PEMEC applications. 2 H + + 2 e − → H 2 H 2 O → 0.5 O 2 + 2 H + + 2 e − …”

Advancing the Electrochemistry of Gas‐Involved Reactions through Theoretical Calculations and Simulations from Microscopic to Macroscopic

“…also simulated by FES that metal oxides can cause so‐called LEF enhancement and induce interfacial water enrichment and reorientation, which accelerated the diffusion of hydrated K + and promoted the HER. [ 176 ]…”

“…Besides, Wei et al also simulated by FES that metal oxides can cause so-called LEF enhancement and induce interfacial water enrichment and reorientation, which accelerated the diffusion of hydrated K + and promoted the HER. [176] In addition to LEF, the conductivity of catalyst and the adsorption/desorption capacity of intermediates and products in the HER process can also be simulated and explored by FES. Chu's group designed a 3D layered nanoflower structure composed of MoSe 2 and graphene with excellent HER performance.…”