Solution plasma-assisted synthesis of oxyhydroxides for advanced electrocatalytic water splitting

•MNiOOH (M = Fe, Co, Ni, and Cu) nanosheets were prepared on nickel foam surface by solution plasma.•MNiOOH oxyhydroxides were employed as electrocatalysts for efficient water splitting.•FeNiOOH exhibited excellent HER and OER performance. The fabrication of simple, fast, environmentally friendly, inexpensive, and catalytically active materials is of great importance for both efficient electrolytic water low-carbon hydrogen production technology and environmental remediation. Here, we report a solution plasma method, specifically, the formation of oxyhydroxides on nickel foam by solution plasma treatment at room temperature and pressure and without any chemical addition. The eco-friendly method yields a oxyhydroxides layer with numerous active sites on nickel foam. FeNiOOH catalyst exhibits remarkable performance as both HER and OER catalysts, requiring mere overpotentials of 257 and 320 mV, respectively, to achieve a current density of 50 mA cm−2. Moreover, these catalysts demonstrate excellent stability, with only a slight decrease in activity observed after a 50 h stability test. This work provides an effective strategy for rationalizing self-supporting electrodes composed of nanostructured arrays on conducting substrates, creating new opportunities for finding advanced materials. We believe that solution plasma-modified high-surface area nickel foam can be used in various electrocatalytic processes.