Advances and Challenges in Industrial-Scale Water Oxidation on Layered Double Hydroxides

A substantial effort is devoted to the development of efficient electrolyzers made of earth-abundant elements for lowtemperature industrial-scale water electrolysis. However, a large current density leads to the decline of the reaction kinetics that result from the decrease of local pH, the irreversible redox states of active metal sites, and the structure and composition collapse. Currently, the transition metal layered double hydroxides (LDHs) are proven as efficient alkaline oxygen evolution catalysts and demonstrate promising current density, generally at the scale of 10 mA cm-2 for the potential solar-driven catalysis concerning 10% solar-to-fuels efficiency. However, there is very limited progress in understanding the activity and stability degradation mechanism of LDHs at high current density, for instance above 100 mA cm-2. Here we introduce the current advances in achieving activity enhancement by tuning the composition, structure, and morphology of LDHs and present the degradation mechanism during the electrolysis under oxidative alkaline environments, long-term operation, and voltage fluctuations. Finally, we present the state-of-the-art approaches to stabilize the overall performance of LDHs for water oxidation and provide an outlook in this field.

Automated summary

This article discusses the development of efficient electrolyzers made of earth-abundant elements for low-temperature industrial-scale water electrolysis, focusing on the impact of active metal sites, structure, and composition on reaction kinetics as well as the current density issues of LDHs. Moreover, it introduces the degradation mechanism of LDHs in oxidative alkaline environments and approaches to stabilize the overall performance of LDHs.