Ameliorating water splitting by entropy regulation and electronic structure engineering on pristine Prussian blue analog

Electrochemical water splitting is the most promising green method for hydrogen production. In this work, the traditional Prussian blue analogs were endowed with the new concept of high entropy to bring a breakthrough in electrocatalytic performance. A classic two-step synthetic strategy was employed to fabricate the high-entropy FeCoNiCr 6 P nanoparticle via phosphating the FeCoNiCr 6, which was prefabricated using a facile coprecipitation method. The phosphides can trap protons by acting as bases to promote the discharge step faster. FeCoNiCr 6 P requires a lower overpotential of only 268.3 mV at a current density of 100 mA cm −2 for OER. The FeCoNiCr 6 P//FeCoNiCr 6 P electrochemical water splitting couple can realize a low voltage of 1.58 V to at 10 mA cm −2 current density. Furthermore, the electronic states and coordination environment of catalyst active sites were investigated to get deeper insight into material design.