Superhydrophilic/underwater superaerophobic self-supporting CuS/Cu foam electrode for efficient oxygen evolution reaction

Hydrogen production by electrochemical overall water splitting is an economic and green approach to resolve the looming energy and environmental crisis. However, the electrocatalytic oxygen evolution reaction (OER) generally occurs at low rate due to the delayed reaction kinetics of four-electron transfer. Herein, a kind of crater-like micro-nano structure CuS three-dimensional electrode that was supported on a Cu foam was prepared and used as an electrode anode for overall water splitting. The superhydrophilic/underwater superaerophobic structure can significantly reduce the bubble adhesion on the electrode surface and improve the OER performance. The CuS/CF electrode showed good wettability and superaerophobicity with an underwater contact angle of 153.5°. The CuS/CF (CuS/Cu foam) electrode has been proved to have excellent electrocatalytic activity for water decomposition. In 1.0 M KOH solution, the OER overpotential is 350 mV at 10 mA cm−2 and the Tafel slope is 83 mV dec−1. In acidic medium of 0.5 M H2SO4 solution, the overpotential of hydrogen evolution (HER) is 134 mV at 10 mA cm−2 and the Tafel slope is 114 mV dec−1. The underwater superaerophobic electrode still has strong stability after 10 h test. This work provides a new potential electrochemical catalyzed approach to water decomposition by constructing a super-infiltration electrode.