A surface configuration strategy to hierarchical Fe-Co-S/Cu2O/Cu electrodes for oxygen evolution in water/seawater splitting

Abstract Fabrication of low-cost but effective catalytic electrode for oxygen evolution is an important issue for water splitting. In this study, a self-supporting electrode composed of hierarchical microstructure was fabricated by a surface configuration strategy. Thin nanosheet-like Fe-Co sulfide units were loaded on one-dimensional Cu2O/Cu framework through an electrodeposition route, during which Cu(OH)2 nanowires were used as a template to generate one-dimensional Cu2O/Cu framework. Benefiting from the unique hierarchal microstructure that can expose more catalytic active centers and facilitate the release of oxygen bubbles, this self-supported Fe-Co-S/Cu2O/Cu catalytic electrode presents superb catalytic activity towards oxygen evolution. In 1 M KOH, the obtained catalytic electrode only requires an overpotential of 338 mV for 50 mA cm−2. It is proposed that oxyhydroxides involved with sulfur species formed on the electrode surface during oxygen evolution process, while the hierarchical microstructure of the electrode keeps. Especially, the Fe-Co-S/Cu2O/Cu catalytic electrode shows excellent catalytic performance for salty water and real seawater splitting, and demonstrates excellent catalytic stability. This study provides an effective strategy towards the fabrication of metal sulfide electrode with hierarchical microstructure for water/seawater splitting.