Superhydrophilic\nand Underwater Superaerophobic Dual-Function\nPeony-Shaped Selenide Micro–nano Array Self-Supported Electrodes\nfor High-Efficiency Overall Water Splitting Driven by Renewable Energy

With the intensification of global environmental pollution\nand\nresource scarcity, hydrogen has garnered significant attention as\nan ideal alternative to fossil fuels due to its high energy density\nand nonpolluting nature. Consequently, the urgent development of electrocatalytic\nwater-splitting electrodes for hydrogen production is imperative.\nIn this study, a superwetting selenide catalytic electrode with a\npeony-flower-shaped micronano array (MoS<sub>2</sub>/Co<sub>0.8</sub>Fe<sub>0.2</sub>Se<sub>2</sub>/Ni<sub><i>x</i></sub>Se<sub><i>y</i></sub>/nickel foam (NF)) was synthesized on NF\nvia a two-step hydrothermal method. The optimal catalytic activity\nof cobalt–iron selenide was achieved by adjusting the Co/Fe\nratio. The intrinsic catalytic activity of the electrodes was enhanced\nby incorporating transition metal selenides, which then served as\na precursor for the subsequent loading of MoS<sub>2</sub> nanoflowers\non the surface to fully expose the active sites. Furthermore, the\nsuperwetting properties of the electrode accelerated electrolyte penetration\nand electron/mass transfer, while also facilitating bubble detachment\nfrom the electrode surface, thereby preventing “bubble shielding\neffect”. This resulted in superior oxygen evolution reaction\n(OER) and hydrogen evolution reaction (HER) performance, as well as\noverall water splitting capabilities. In a 1.0 M KOH solution, the\nelectrode required only 166 and 195 mV overpotential to achieve a\ncurrent density of 10 mA cm<sup>–2</sup> for OER and HER, respectively.\nWhen functioning as a bifunctional catalytic electrode, only 1.60\nV of voltage was necessary to drive the electrolyzer to reach a current\ndensity of 10 mA cm<sup>–2</sup>. Moreover, laboratory simulations\nof wind and solar energy-driven water splitting validated the feasibility\nof establishing a sustainable energy-to-hydrogen production chain.\nThis work provides new insights into the preparation of low-overpotential,\nhigh-catalytic-activity superhydrophilic and underwater superaerophobic\ncatalytic electrodes by rationally adjusting elemental ratios and\nexploring changes in electrode surface wettability.