Boosting Electrochemical Water Oxidation on NiFe (oxy) Hydroxides by Constructing Schottky Junction toward Water Electrolysis under Industrial Conditions

Abstract

The practical deployment of promising NiFe‐based oxygen evolution reaction (OER) electrocatalysts is heavily limited due to the constrain in both stability and activity under industrial conditions. Herein, a 3D free‐standing NiFe(oxy)hydroxide‐based electrode with Schottky junction is constructed, in which NiFe(oxy)hydroxide (NiFe(OH)x) nanosheets are chemically assembled on the top of metal‐like Ni3S2 scaffold that are in situ formed on commercial Ni mesh. Such an assembly enhances the binding strength of each components, promotes the charge transfer across the interfaces, and modulates the electronic and nanostructural features of NiFe(OH)x. Consequently, the electrode delivers current densities of as high as 500 and 1000 mA cm−2 for OER at overpotentials of only 248 and 270 mV with long‐term stability in 1 m KOH. When it was paired with a NiMo hydrogen evolution cathode in a practical two‐electrode system, a current density of 1000 mA cm−2 is achieved at a low cell voltage of ≈1.61 V at 80 °C in 30% KOH without losing performance for at least 1500 h. This is the best performance reported thus far for alkaline water electrolysis under industrial conditions, demonstrating its great potential for practical applications.

Construction of Synergistic Ni3S2‐MoS2 Nanoheterojunctions on Ni Foam as Bifunctional Electrocatalyst for Hydrogen Evolution Integrated with Biomass Valorization

“…[ 6–8 ] Therefore, considerable effort has been devoted to adapting alternative anodic reactions. [ 9–11 ] The electrochemical oxidation of 5‐hydroxymethylfurfural (HMF) has emerged as a promising alternative due to its low oxidation potential and high added value. Although various catalysts including NiCoFe LDH, [ 12 ] CoO‐CoSe 2 , [ 13 ] Ni x B, [ 14 ] and NiCo 2 O 4 [ 15 ] have been reported as potential electrocatalysts for HMF oxidation, they are only efficient for HMF oxidation and show poor HER performance.…”

Amorphous–crystalline FeNi2S4@NiFe–LDH nanograsses with molten salt as an industrially promising electrocatalyst for oxygen evolution

“…Moreover, in comparison with FeNi 2 S 4 (343 mV), NiFe-LDH (405 mV) and NiFe foam (456 mV), the FeNi 2 S 4 @NiFe-LDH only needs an ultralow overpotential of 306 mV to achieve a large current density of 1000 mA cm −2 , indicating that the synergetic effect between amorphous NiFe-LDH and crystalline FeNi 2 S 4 plays a vital role in achieving extraordinarily high OER activity on FeNi 2 S 4 @NiFe-LDH. 33 Fig. 3b displays the comparison of overpotentials at 100, 500 and 1000 mA cm −2 for FeNi 2 S 4 @NiFe-LDH and other references during the synthesis.…”

“…32 In principle, the direct combination of NiFe-LDH and a conductive substrate by a novel corrosion strategy can alleviate this problem. 33 Zou et al adopted an ultrafast hydrolysis method to construct amorphous Ni-Fe bimetallic hydroxides on Ni 3 S 2 surfaces. The composite Ni-Fe-OH@Ni 3 S 2 /NF electrocatalyst shows remarkable catalytic ability for the OER at large current densities, and only acquired 240 mV to achieve 100 mA cm −2 .…”

Wood‐Derived Monolithic Catalysts with the Ability of Activating Water Molecules for Oxygen Electrocatalysis

“…These shortcomings limit their application in the field of next-generation energy conversion. [26,27] Hence, the coupling of IMPs on the monolithic NWCC is able to improve the proton generation efficiency and stabilize the IMPs particles. The activating water strategy promotes the proton generation and enhances the ORR while enhances the OER activity.…”