Improved Electrocatalytic Performance in Overall Water Splitting with Rational Design of Hierarchical Co₃O₄@NiFe Layered Double Hydroxide Core‐Shell Nanostructure

Abstract

The development of low‐cost and highly reactive electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in basic media is still a great challenge. Herein, we design a three‐dimensional Co3O4@NiFe‐LDH (LDH: layered double hydroxide) core‐shell nanostructure on Ni foam, in which the core Co3O4 nanowires play a key role in the stability and the shell NiFe‐LDH nanosheets provide the main active sites for electrocatalytic water splitting. The as‐prepared Co3O4@NiFe‐LDH exhibits excellent electrocatalytic activity for OER with a low overpotential of 269 mV at a current density of 100 mA cm−2, a small Tafel slope of 66 mV dec−1, and excellent stability without degradation over 40 h. Furthermore, the sample also demonstrates robust performance for HER with a low overpotential of 74 mV at a current density of 10 mA cm−2. Most importantly, when employing the Co3O4@NiFe‐LDH/NF as both anode and cathode, only 1.56 V is needed to achieve a current density of 10 mA cm−2, which is lower than the combination of Pt/C and IrO2 catalysts for overall water splitting. This work provides a significant strategy toward the rational design of novel core‐shell electrocatalysts for overall water splitting.

Holey Assembly of Two‐Dimensional Iron‐Doped Nickel‐Cobalt Layered Double Hydroxide Nanosheets for Energy Conversion Application

“…[18] It was proposed that doping of Mn 2 + could stabilize the lower oxidation state of Ni and promotet he formation of active b-NiOOH along with activation of the basal plane of NiFe-LDH. Furthermore, the OER activity of LDHs can also be enhanced by hybridization with carbonaceous materials such as carbon nanotubes (CNTs), [19] reduced graphene oxide (rGO), [20] macro/mesoporousc arbon) [21] or non-carbonaceousm aterials, such as metal oxides (NiO, [22] Co 3 O 4, [23] and NiCo 2 O 4 ), [24] metal phos-phides( Ni 5 P 4 /NiP 2, [25] Cu 3 P, [26] and NiCoP), [27] metal sulfides (NiCo 2 S 4 ), [28] and metal selenides (NiSe x ) [29] owing to synergistic effects and improved conductivity arising from interfacial electron transfer.…”

One‐Step Synthesis of NiFe Layered Double Hydroxide Nanosheet Array/N‐Doped Graphite Foam Electrodes for Oxygen Evolution Reactions

“…Among these candidates, NiFe layered double hydroxide (LDH) catalysts have been attracting more and more research attention in electrocatalysis because of their special nanostructure, tunable composition, and large specific surface area. [22][23][24][25][26][27] To improve the intrinsic conductivity, LDH coupled with carbonaceous materials (graphene, carbon nanotubes, and carbon quantum dots etc.) has been widely explored.…”

“…As reported, low‐cost transition metals and their derivatives, especially Ni based oxides, hydroxides, sulfides, and phosphides have been indicated as favorable candidates for water splitting because of their earth abundance and high catalytic performance characteristics. Among these candidates, NiFe layered double hydroxide (LDH) catalysts have been attracting more and more research attention in electrocatalysis because of their special nanostructure, tunable composition, and large specific surface area . To improve the intrinsic conductivity, LDH coupled with carbonaceous materials (graphene, carbon nanotubes, and carbon quantum dots etc.)…”

Layered FeCoNi double hydroxides with tailored surface electronic configurations induced by oxygen and unsaturated metal vacancies for boosting the overall water splitting process

“…66 Such a high performance and low-cost F-FeCoNi-Ov LDH/NF electrocatalyst can be considered as a prominent candidate for overall water splitting to produce hydrogen gas. Besides, the comparisons of the water oxidation performance between this work and other reports [67][68][69][70][71][72][73][74][75] are listed in Fig. 9d.…”