Achieving High‐Performance Electrocatalytic Water Oxidation on Ni(OH)₂ with Optimized Intermediate Binding Energy Enabled by S‐Doping and CeO₂‐Interfacing

Abstract

The adsorption energy of the reaction intermediates has a crucial influence on the electrocatalytic activity. Ni‐based materials possess high oxygen evolution reaction (OER) performance in alkaline, however too strong binding of *OH and high energy barrier of the rate‐determining step (RDS) severely limit their OER activity. Herein, a facile strategy is shown to fabricate novel vertical nanorod‐like arrays hybrid structure with the interface contact of S‐doped Ni(OH)2 and CeO2 in situ grown on Ni foam (S‐Ni(OH)2/CeO2/NF) through a one‐pot route. The alcohol molecules oxidation reaction experiments and theoretical calculations demonstrate that S‐doping and CeO2‐interfacing significantly modulate the binding energies of OER intermediates toward optimal value and reduce the energy barrier of the RDS, contributing to remarkable OER activity for S‐Ni(OH)2/CeO2/NF with an ultralow overpotential of 196 mV at 10 mA cm−2 and long‐term durability over 150 h for the OER. This work offers an efficient doping and interfacing strategy to tune the binding energy of the OER intermediates for obtaining high‐performance electrocatalysts.

Facilitating active NiOOH formation via Mo doping towards high-efficiency oxygen evolution

“…The results reveal a prominent transition peak at 1.43 V ( vs. RHE) for the NiFeMo-LDH, which is lower than that of NiFe-LDH (1.53 V). 56 The potential that the phase angle peak occurs is in agreement with the OER onset potential of the LSV curves. 57 This also suggests faster reaction kinetics for water oxidation, indicating a pronounced reduction in charge transfer resistance for the NiFeMo-LDH catalysts compared to NiFe-LDH.…”

“…67,68 The current difference caused by the alcohol oxidation reaction can reveal the catalyst surface coverage of *OH, further indicating the adsorption of *OH. 69 The greater ethanol oxidation reaction current density of the NiFe-LDH catalyst suggests its stronger *OH adsorption than that of the NiFeMo-2 catalyst, indicating that the incorporation of Mo modulates the adsorption energy of *OH in NiFeMo-2, thus promoting the dehydrogenation process. The catalytic behaviour during the OER process was thoroughly investigated by in situ Raman spectroscopy, which can unravel the evolution of active species under various applied potentials and study the surface dynamic reconstruction process of the catalyst.…”

Facet-Dependent Lattice Oxygen Activation on Oxygen-Defective Co3O4 for Electrocatalytic Oxygen Evolution Reaction

“…31,34 As displayed in Figure S1 To probe the effect of the crystal facets of oxygen-defective Co 3 O 4 on the OER kinetics, the Tafel slopes for all catalysts were obtained by a steady-state polarization technique to remove the impact of the rate of increase of electrode potential or polarization with the log of the current density. 40,41 As shown in Figures S7−S10 42,43 The intrinsic OER activities of the four samples were explored, and electrochemically active specific surface area (ECSA) was used to normalize their OER LSV plots. The cyclic voltammetry (CV) curves at the non-Faradaic process potential range (Figure S11 This signifies that the (001) facet exhibits better stability as a promising OER electrocatalyst than the (111) facet for the oxygen-defective Co 3 O 4 .…”

“…The smallest angles for Vo-Cubic-Co 3 O 4 at each potential demonstrate that the electrochemical OER process involved more electrons than other catalysts.45−47 These results suggest that the (001)-faceted oxygen-defective Co 3 O 4 possesses superior electron transfer ability and OER kinetics compared to those of (111)-faceted oxygen-defective Co 3 O 4 .To further investigate the mechanism for the improved OER activity, the values of apparent activation energy (denoted as E app ) for the four catalysts were calculated on the basis of the temperature-dependent OER performance. The LSV curves of Cubic-Co 3 O 4 , Vo-Cubic-Co 3 O 4 , T-Oc-Co 3 O 4 , and Vo-T-Oc-Co 3 O 4 samples were measured at different temperatures(30,40,50,60, and 70 °C) as shown in FigureS19. It is expected that the OER performances of all the catalysts are enhanced with the increase of temperature.…”

“…To probe the effect of the crystal facets of oxygen-defective Co 3 O 4 on the OER kinetics, the Tafel slopes for all catalysts were obtained by a steady-state polarization technique to remove the impact of the rate of increase of electrode potential or polarization with the log of the current density. , As shown in Figures S7–S10, steady-state chronoamperometric responses of Cubic-Co 3 O 4 , Vo-Cubic-Co 3 O 4 , T-Oc-Co 3 O 4 , and Vo-T-Oc-Co 3 O 4 were performed to extract their Tafel slopes. The obtained Tafel plots for the samples are depicted in Figure c, illustrating that the Tafel slope of Vo-Cubic-Co 3 O 4 is 58.2 mV/dec, which is much smaller than other catalysts Cubic-Co 3 O 4 (96.9 mV/dec), T-Oc-Co 3 O 4 (107.3 mV/dec), and Vo-T-Oc-Co 3 O 4 (78.8 mV/dec).…”