Advanced Self‐Standing Electrodes for Water Electrolysis: A Review on Strategies for Further Performance Enhancement

Abstract

The large‐scale application of water electrolysis to produce high purity H2 greatly relies on the development of highly efficient and stable catalysts. In this field, substantial progress has been witnessed during the past years, and self‐standing electrode represents a remarkable milestone. A series of problems associated with common powder catalysts, including insufficient active sites exposure, limited mass transfer, easily peeling off, etc., can be solved by the construction of self‐standing electrode. However, there is still room for further performance enhancement. Therefore, the latest achievements and challenges on the design of advanced self‐standing electrodes for water electrolysis is summarized in this review. Firstly, we outline the methods for controllable synthesis of self‐standing electrodes. Then, particular attention is paid to the adopted strategies for tuning the structure and surface electron configuration of the electrodes, as well as the related performance enhancement mechanisms. Finally, remaining challenges and future perspectives for development of advanced self‐standing electrodes for water electrolysis are concluded.

Highly Active and Stable NiCuMo Electrocatalyst Supported on 304 Stainless Steel Porous Transport Layer for Hydrogen Evolution in Alkaline Water Electrolyzer

“…After a transitory of ≈1 h, the overpotential for HER remains quite stable for (at least) 100 h, with a value of 165 ± 45 mV, demonstrating the high stability of this electrode. This is the lowest overpotential value if compared with other values reported in the literature for stability tests carried out at 100 mA cm −2 for 100 h. [ 23,39 ]…”

“…After a transitory of ≈1 h, the overpotential for HER remains quite stable for (at least) 100 h, with a value of 165 ± 45 mV, demonstrating the high stability of this electrode. This is the lowest overpotential value if compared with other values reported in the literature for stability tests carried out at 100 mA cm −2 for 100 h. [23,39] To further demonstrate the outstanding stability of 3Mo electrocatalyst, the electrode was studied after the stability test with morphological characterization and evaluating Ni, Cu, and/or Mo loss during 100 h polarization by ICP-OES.…”

Self-standing 2D/2D Co3O4@FeOOH nanosheet arrays as promising catalysts for the oxygen evolution reaction

“…Moreover, as OER occurs at the well-known three-phase boundary, an OER catalyst appealing for optimized electrode architecture for the efficient exposure of active sites and facilitating mass transfer. [26][27][28] For instance, as reported by Zheng and coworkers, a core-shell Ni 3 S 2 @MoS 2 /FeOOH heterostructure in a hierarchical manner was constructed by coupling FeOOH with Ni 3 S 2 @MoS 2 nanowire arrays. 29 In these heterostructures, the synthesis of FeOOH mostly relies on the hydrolysis of Fe 3+ under various conditions, for example, under hydrothermal or electrodeposition conditions.…”

The progress of research on vacancies in HMF electrooxidation

“…Surface defects, considered critical in electrocatalyst design, serve as key factors in modulating catalytic activity and selectivity ( Ares and Novoselov 2022 ; Yan et al, 2022 ). Among them, point defects, which encompass vacancies, substitutions, insertions, and interstitial atoms within the crystal lattice, can influence the electronic structure and surface reactivity of catalysts via doping or inherent mechanisms ( Xiang et al, 2019 ; Xiang and Wang 2022 ; Huang et al, 2023 ; Wang et al, 2023 ). Line defects, such as dislocations and grain boundaries, constitute one-dimensional imperfections altering the local electronic environment and surface morphology, potentially affecting catalytic activity.…”