Optimizing noble metals exploitation in water oxidation catalysis by their incorporation in layered double hydroxides

Water oxidation (WO) is considered the ideal process for the generation of electrons and protons necessary for the production of sustainable fuels. The unfavorable kinetics of this reaction requires the development of highly efficient catalysts (WOCs). The most promising performance has been obtained with noble metal based systems, which however pose challenges for the careful exploitation of these precious elements. In this Review, one of the most promising strategies for the development of WOCs in a ‘noble metal atom economy’ fashion is described, that is, the incorporation of these metals in layered double hydroxides (LDHs) of earth abundant elements. A rapidly raising number of studies demonstrate that excellent catalytic activity and durability can be obtained by following this strategy. The strong electronic coupling between noble metal nanoparticles or single atoms and the LDHs matrix is typically responsible for such intriguing results. Interestingly, noble metal incorporation as low as 1 wt% allows to boost the catalytic performance of intrinsically active systems like NiFe-LDHs, but also to activate otherwise inert materials like ZnAl-LDHs.