Development of Electrochemical Water Splitting with Highly Active Nanostructured NiFe Layered Double Hydroxide Catalysts: A Comprehensive Review

Abstract

Electrochemical water splitting is a feasible and effective method for attaining hydrogen, offering a mechanism for renewable energy solutions to combat the world's energy crises due to the scarcity of fossil fuels. Evidently, the viability and stability of the electrocatalysts are fundamental to the electrochemical water-splitting process. However, the net efficiency of this process is noticeably hindered by the kinetic drawbacks related to the OER. Hence, NiFe LDH has been widely used as a highly efficient OER and HER catalyst material due to its unique nanostructure, tunable composition, and favorable electronic structure. This review offers a systematic analysis of the latest progress in the fabrication of functional NiFe LDH catalysts and associated fabrication strategies, structure optimizations, and performance improvements. Special emphasis is given to understanding the role of nanostructure engineering in increasing active site accessibility, enhancing the effectiveness of subsequent electron transfer, and boosting the intrinsic catalytic activity for HER and OER. Moreover, we discuss the influence of doping, defects, and the formation of heterostructures with other materials on the OER and HER activities of NiFe LDHs. Additional accounts of basic structures and the OER and HER catalytic activities are provided, along with an enhanced theoretical understanding based on DFT studies on the NiFe LDH. Moreover, the limitations and potential developments of the work focus on the need for existing synthesis approaches, the stability of the NiFe LDH catalysts, and their insertion into working electrochemical processes. This review is a comprehensive analysis of the current state of research and developments in the use of NiFe LDH catalysts for the electrochemical water-splitting process to foster improved development of sustainable hydrogen sources in the future.