Robust FeCoP nanoparticles grown on a rGO-coated Ni foam as an efficient oxygen evolution catalyst for excellent alkaline and seawater electrolysis

Electrochemical water splitting is a potential green hydrogen energy generation technique. With the shortage of fresh water, abundant seawater resources should be developed as the main raw material for water electrolysis. However, since the precipitation reaction of chloride ions in seawater will compete with the oxygen evolution reaction (OER) and corrode the catalyst, seawater electrolysis is restricted by the decrease in activity, low stability, and selectivity. Rational design and development of efficient and stable catalysts is the key to seawater electrolysis. Herein, a high-activity bimetallic phosphide FeCoP, grown on a reduced graphene oxide (rGO)-protected Ni Foam (NF) substrate using FeCo Prussian Blue Analogue (PBA) as a template, was designed for application in alkaline natural seawater electrolysis. The OER activity confirmed that the formed FeCoP@rGO/NF has high electrocatalytic performance. In 1 M KOH and natural alkaline seawater, the overpotential was only 257 mV and 282 mV under 200 mA cm(-2), respectively. It also demonstrated long-term stability up to 200 h. Therefore, this study provides new insight into the application of PBA as a precursor of bimetallic phosphide in the electrolysis of seawater at high current density.

Automated summary

Electrochemical water splitting is a potential technique for green hydrogen energy generation, but the use of seawater as raw material is restricted by the decrease in activity, low stability, and selectivity caused by the precipitation reaction of chloride ions. In this study, a FeCoP catalyst grown on a rGO-protected Ni Foam substrate showed high electrocatalytic performance in alkaline seawater electrolysis, with low overpotentials and long-term stability.