Co3O4/stainless steel catalyst with synergistic effect of oxygen vacancies and phosphorus doping for overall water splitting

The electrolysis of water into hydrogen and oxygen provides an effective means of storing electrical energy indirectly.The current challenge is to design an optimal catalyst that exhibits low overpotentials,long-term stability,universal availability,and only uses inexpensive materials.Herein,a Co3O4nanoflower/stainless steel(P-Ov-CO3O4/SS) catalyst with both oxygen vacancies(Ovs) and phosphorus doping was perfectly prepared via a simple three-step method.The Ovs promoted charge transfer and accelerated the electrocatalysis,while P finely tuned the surface charge state.This resulted in numerous active sites for catalysis,and the synergistic effect of phosphorus doping and oxygen vacancies was finely demonstrated.The resultant electrocatalyst exhibited low hydrogen evolution overpotentials of 118 mV(-10 mA·cm-2) and 242(-200 mA·cm-2),as well as oxygen evolution overpotentials of 327 mV(100 mA·cm-2) and 370 mV(200 mA·cm-2),owing to the excellent synergistic effect of the Ovs and low-temperature phosphating.Moreover,P-Ov-Co3O4/SS//P-Ov-Co3O4/SS exhibited a low water splitting voltage of 1.681 V at 20 mA.cm-2.These findings will enable the synthesis of novel high-performance electrocatalysts for overall water splitting.