Prussian blue- and Prussian blue analogue-derived materials: progress and prospects for electrochemical energy conversion

Electrochemical energy conversion with efficient catalyst systems can be utilized for the production of clean and sustainable energy. Extensive studies have been carried out in last two decades to replace state-of-the-art noble metal catalysts by efficient transition metal based materials. Transition metal salts, organometallic compounds, metal organic frameworks (MOFs), polyoxometallates (POMs) etc. have been explored as the precursors for the materials synthesis. In this respect, Prussian blue (PB) and Prussian blue analogues (PBAs) attain special interest as the precursors of the materials due to their facile, robust and cost effective synthesis, highly porous structure and designed morphology. Moreover, PBAs can be prepared with multi-metal system, core-shell and hollow structure. A series of materials have been synthesized by employing PB or PBA with tailorable properties like exposed facets, porous structure, high electrochemical surface area, improved electron transport and accessible catalytic sites. These materials are found to produce excellent electrochemical activity for oxygen evolution, hydrogen evolution, oxygen reduction as well as overall water splitting. In this review, we have focused on the recent progress in PB and PBA derived materials describing their synthesis, diverse architecture, morphology and enhanced electrochemical performances. The major achievements and challenges related to PB and PBA derived materials for the energy conversion have been discussed with the direction of possible future advancement.