Recent progress in first row transition metal Layered double hydroxide (LDH) based electrocatalysts towards water splitting: A review with insights on synthesis

Electrocatalytic water splitting plays a pivotal part towards the construction of sustainable and environmental benign energy conversion and generation sector that ultimately addresses the global fossil fuel dependence. Hence, robust, highly active and budget-friendly earth-abundant materials are required that catalyses hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting (OWS) under low overpotential with high efficiency. First row transition metal based Layered double hydroxide (LDH) catalysts are promising alternatives of noble metal counterparts because of their advantageous physio-chemical properties. This review summarises, recent research efforts towards fabrication of LDHs systems including adopted modification strategies; doping/defect engineering, exchanging interlayer anion, nanostructured morphology, designing hierarchical heterostructure or nanocomposites, etc for improved activity. Furthermore, the review describes the activity of different LDH derived materials along with brief explanation of reaction mechanisms and important parameters relating to electrocatalytic water splitting. Moreover, a comprehensive literature overview highlighting recent achievements on LDH and derived electrocatalysts towards HER, OER and OWS performance is also discussed in details. Finally, a personal perspective is provided on challenges and future opportunities for developing superior LDHs based electrocatalysts for realistic applications.