Prussian blue analog-derived Fe-Co-P as excellent electrocatalyst for oxygenevolution reaction

Due to the environmental deterioration caused by overuse of fossil fuels and generating largeamounts of greenhouse gases, it is significant to develop efficient and economical techniques forproducing green and renewable energy sources [۱]. Among the competitive candidates, the rapidprogress in hydrogen and oxygen production via electrochemical water splitting (ECWS) has madeit a promising solution [۲]. ECWS is composed of oxygen evolution reaction (OER) and hydrogenevolution reaction (HER). However, the sluggish kinetics of OER due to its four-electron transferprocess is still a challenge, which greatly limits the electrocatalytic efficiency [۲]. In addition to,noble metal-based oxides, such as RuO۲ and IrO۲, are recognized as state-of-the-art OERelectrocatalysts [۳] and since these catalysts are expensive, thus extensive research is being doneto replace them. In this regard, transition metal salts, organometallic compounds, metal-organicframeworks (MOFs), polyoxometalates (POMs), Prussian blue (PB) and other nanostructures havebeen investigated. Among them, PB and Prussian blue analogs (PBAs) are of special interest, asthey are excelent catalysts and precursor materials due to their easy, robust and cost-effectivesynthesis, highly porous structure and designed morphology, improved electron transport andaccessible catalytic sites [۱]. The PB, termed ferric ferrocyanide, is a polynuclear complexincluding transition metal (Fe) and cyanide group (CN) and as a MOF has had industrialapplications since the ۱۸th century, which initial structural forms discovered by Keggin and Miles.Their proposed form showed that PB comprises iron ions including ferrous (Fe۲+) and ferric (Fe۳+)located at the corners of a cube which is linked by cyanide ligands with the general formula ofFe۳+۴[Fe۲+(CN)۶]۳, their assembly can be achieved by mixing ferric or ferrous withhexacyanoferrate ions and different oxidation states of iron [۴]. Which, PB-based catalysts it hasshown broad application in different disciplines especially OER based on publications since ۱۹۸۶.Herein, FeCoP nanocages have been obtained from FeCo-PBA nanocube precursor via a facilephosphorization route. The porous hollow structure and unique multi-void interior provide exposedactive sites and a large surface area. In the FeCoP catalyst, both P and metals (Fe and Co) serve asactive sites, and the synergism between them induces an optimized electronic structure. Finally,these nanocage structures showed good catalytic activity for OER.

کلیدواژه ها:

Prussian blue ، Water splitting ، Oxygen evolution reaction