Self-Supporting np-AlFeNiO Bifunctional Electrode Material for Electrochemical Water Splitting Prepared by Electrooxidation

Hydrogen production through water splitting is a promising path to develop renewable green energy. Effective, stable, and low-cost catalysts are the key to water splitting. In the present work, a series of self-supporting nanoporous alloys are prepared by using a dealloying process followed by electrooxidation. Among them, the np-AlFeNiO-4s sample exhibits remarkable activity (10 mA cm−2 at 32 mV for the HER and 278 mV for the OER) and good long-term stability (100 h) in alkaline conditions for both the HER and the OER. It only requires 1.56 V to reach 10 mA cm−2 current density for total water splitting performance. The very short time of electrooxidation can significantly improve the HER performance. Electrooxidation makes the metal and metal oxide sites on the electrode surface effectively coupled, which greatly enhances the kinetic rate of the Volmer and Heyrovsky steps. Appropriate electrooxidation is a rapid and easy way to improve the activity of the electrocatalyst, which has a broad application prospect in electrochemical water splitting.