NiCo-Based Electrocatalysts for the Alkaline Oxygen Evolution Reaction: A Review

Abstract

Electrocatalytic water splitting is a sustainable way to produce hydrogen energy, but the oxygen evolution reaction (OER) at the anode has sluggish kinetics and low energy conversion efficiency, which is the major bottleneck for large-scale hydrogen production. The design and synthesis of robust and low-cost OER catalysts are crucial for the OER. NiCo-based electrocatalysts have suitable atomic and electronic structures, and show high activity and stability during the OER process. Recently, significant progress has been made in regulating the structure and composition of NiCo-based catalysts and understanding the nature of catalysis, especially the OER mechanism, catalytic active sites, and structure–activity relationship. In this work, we summarized and discussed the latest development of NiCo-based electrocatalysts in the OER, with particular emphasis on catalyst design and synthesis, strategies for boosting OER performance, and understanding the nature of catalysis from experimental and theoretical perspectives. The OER mechanism, some activity descriptors, and atomic and electronic structure–activity relationships based on NiCo-based electrocatalysts are unveiled. Finally, some challenges and futuristic outlooks for improving the performance of NiCo-based electrocatalysts are proposed, and we hope this review can provide guidance for the design of more efficient NiCo-based electrocatalysts.

Stabilization of Co oxide during oxygen evolution in alkaline media by the introduction of Mn oxide

“…Electrodes with similar composition (Co,Mn-and Co-based oxide) investigated in alkaline pH (13)(14), [58][59][60][61][62] showed 10 in a range of 320-430 mV, which tend to increase under OER conditions, thus agreeing with the observations herein. Although the introduction of a second transition metal into the Co oxide structure has reduced the overpotential in some cases, [39,[63][64][65] while it was increased in other cases. [66] Catalytic trends can also be followed using the maximum current density (jmax, at an ohmic drop-corrected potential (E-iRu) of approximately 1.73 V vs. RHE) over cycling.…”

Interfacial Engineering of Two‐Dimensional MoN/MoO2 Heterostructure Nanosheets as a Bifunctional Electrocatalyst for Overall Water Splitting

“…[2] As a new type of energy source, hydrogen is expected to become the most potential candidate to replace fossil fuel in the future in arrears to its high energy density and almost zero pollution. [3,4] At the present time, the hydrogen production by electrolysis of water is one of the cleanest ways. However, the two-part main reactions involved in the water electrolysis, namely hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), are slow, resulting in high energy consumption.…”

“…The exponential rise in energy demand is leading to global energy crisis and the resulting environmental problem from fossil fuels, it is crucial to develop clean and sustainable energy [2] . As a new type of energy source, hydrogen is expected to become the most potential candidate to replace fossil fuel in the future in arrears to its high energy density and almost zero pollution [3,4] . At the present time, the hydrogen production by electrolysis of water is one of the cleanest ways.…”

Unveiling the mechanism of high-performance hydrogen evolution reaction on noble-metal-free (113)-faceted Ni3C: ab initio calculations

“…The electronic structure can be effectively adjusted by Ni, indicating the great potential of Ni-based catalysts in electrocatalysis. 23 Yan et al dispersed uniform Ni 3 C nanodots in ultrathin N-doped carbon nanosheets and when doped with Fe, the Ni 3 C-based nanosheets exhibited outstanding electrocatalytic properties towards both HER and oxygen evolution reactions (OER). 24 As for HER, Ni 3 C also exhibits great performance.…”