Structural regulation of Fe–Co prussian blue analogues by incorporation of Pt for enhanced electrocatalytic overall water splitting

Abstract

The specific properties of easy manufacturing, open frameworks, and high specific surface area endow prussian blue analogues (PBAs) as promising electrode materials for water splitting. Herein, we reported the successful application of interface engineering strategy to introduce low content of Pt species to boost the electrocatalytic activity of FeCo PBAs by ammonia etching and subsequent calcination. The resulting PtCo alloy modified FeCo PBAs (PtCo–FeCo PBAs) complex reveals modest electrocatalytic activity with low overpotentials (η) of 139 mV for hydrogen evolution reaction (HER) and 310 mV for oxygen evolution reaction (OER) at 10 mA cm−2 in alkaline electrolyte. Remarkably, the PtCo–FeCo PBAs only required small cell voltage of 1.68 V to drive 10 mA cm−2 for overall water splitting and the ideal electrocatalytic activity can be maintained for more than 50 h at a current density of 10 mA cm−2. The structural analysis unveils that the strong interaction between FeCo PBAs host and PtCo alloy resulting in charge redistribution and ultimately lead to high electrocatalytic activity and stability of PtCo–FeCo PBAs for both HER and OER.