Synergistic mechanism of cation-modification and anion-defect dual engineering in FeCo hydroxide/MXene heterostructure for enhanced oxygen evolution

[Display omitted] •Ru-doped FeCo HNs with abundant Ov grown on MXene were prepared.•Optimizing the electronic structure for Ru-FeCo HNs/MXene has been achieved.•Ru-FeCo HNs/MXene show excellent OER performance.•DFT calculations investigated the enhanced OER mechanism. The oxygen evolution reaction (OER) is crucial for electrochemical energy conversion and storage. However, finding OER catalysts that are both effective and durable is still a difficult task. While cation modification and anion-defect engineering are essential for electrocatalysts’ OER activity, MXene-based materials have not been widely studied using these combined strategies. Here, we report a new approach to designing OER catalysts by combining doping and vacancy engineering. We have successfully created Ru-doped FeCo hydroxide nanoarrays with oxygen vacancies on MXene substrates (Ru-FeCo HNs/MXene), significantly enhancing OER kinetics. We use density functional theory (DFT) calculations to demonstrate that the electronic structure is tuned by the combined effects of Ru doping and O vacancy, which lowers the energy barriers for the adsorption/desorption of O-containing intermediates. The optimal Ru-FeCo HNs/MXene achieves outstanding OER activity with a small overpotential of 227 mV at 10 mA cm−2.