Bimetallic (NiCo) metal-organic framework nanosheets with ultrafine Ru as bifunctional electrocatalyst for overall water splitting

Constructing metal-support interface and modulating electronic structure are challenging despite the promising potential in boosting electrocatalytic activity for alkaline overall water splitting. Herein, ultrafine Ru nanoparticles coupled with bimetallic (NiCo) metal-organic framework nanosheets fabricated on CC (Ru/NiCo NDC/CC, NDC: 2,6-naphthalenedicarboxylic) were well-designed to achieve the aforementioned strategies. The coupling effect of Ru and NiCo NDC effectively regulated the electronic structure of Ru/NiCo NDC, which facilitated electron transfer and enhanced the intrinsic activity for overall water splitting. The presence of NiCo NDC nanosheets provided larger surface area for anchoring more ultrafine Ru, which significantly increased electrochemically active area, augmenting electrocatalytic activity for alkaline water splitting. Consequently, the optimal Ru/NiCo NDC/CC required low overpotentials of 61 and 59 mV at −10 mA cm⁻² in acidic and alkaline solution, respectively. Additionally, Ru/NiCo NDC/CC electrocatalyst exhibited a superior activity for OER with an overpotential 228 mV at 10 mA cm⁻². Moreover, the water electrolyzer fabricated by Ru/NiCo NDC/CC as bifunctional electrocatalyst delivered a current density of 10 mA cm⁻² at 1.56 V. This work highlights the feasibility of a dual strategy of constructing metal-support and regulating electronic structure in enhancing electrocatalytic performance.