Mesoporous Nanostructured CoFe–Se–P Composite Derived from a Prussian Blue Analogue as a Superior Electrocatalyst for Efficient Overall Water Splitting

Electrocatalytic water splitting requires the development of attractive and earth-abundant catalysts. In this work, a novel four-part electrocatalyst of mesoporous cobalt/iron phosphorus–selenide nanocomposite (CoFe–Se–P) was derived from hollow CoFe Prussian blue analogues (CoFe-PBA) and combined by phosphatization and selenylation. This novel electrocatalyst displays an efficient and durable bifunctional catalysis performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In view of strong electron interaction among Co, Fe, Se, and P, this four-part electrocatalyst exhibits a lower onset potential of −35.9 mV and an overpotential of −172.5 mV at a current density of 10 mA cm–2 in acidic solution for HER. In alkaline solution, the onset potential and the overpotential are maintained at approximately −33 and −183.1 mV, respectively. Moreover, the proposed CoFe–Se–P catalyst possesses superior OER performance with a lower onset potential of 1.07 V and overpotential of 1.44 V at a current density of 10 mA cm–2 in 0.1 M KOH solution. The versatile electrocatalyst can catalyze water splitting in a two-electrode system at a potential of 1.59 V. The proposed strategy offers insight into the rational design and development of promising electrode materials with distinct architectures for electrochemical energy storage and conversion.