Superwettable Surface-Dependent efficiently electrocatalytic water splitting based on their excellent liquid adsorption and gas desorption

Abstract

Superwettable surfaces has been applied for electrocatalytic water splitting, however, in this phase conversion reaction, the relationship between wettability and electrochemical processes is still unclear. Herein, we demonstrate superwettable surface dependent liquid adsorption and gas desorption for promotion of electrocatalytic reactions, where significant change of wetting state leads to an obvious decrease in overpotential of water splitting reactions. Through an amorphous coating strategy, an intrinsically non-superwettable Ni3S2 catalyst can be transitioned into superwettable Ni3S2 catalyst (Ni3S2@Ni(II)-TC), where water contact angle (WCA) is 0°, implying superhydrophilicity, and bubble contact angle is 153°, meaning under-water superaerophobicity. The Ni3S2@Ni(II)-TC electrode reduces the overpotential of OER from 267 mV to 186 mV and HER from 262 mV to 166 mV at 10 mA cm−2 compared with non-superwettable Ni3S2. The two-electrode electrolyzer performs water electrolysis at 10 mA cm−2 with the voltage of 1.53 V for 20 h without obvious decay.