Tuning coordination microenvironment of V2CTx MXene for anchoring single-atom toward efficient multifunctional electrocatalysis

The rational design of low-cost and high-performance multifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) is essential for efficient overall water splitting and rechargeable metal-air battery. Herein, through density functional theory calculations, we creatively regulate the coordination microenvironment of V2CTx MXene (M-v-V2CT2, T = O, Cl, F and S) as substrates of single-atom catalysts (SACs), and then systematically explore their HER, OER, and ORR electrocatalytic performance. Our results disclose that Rh-v-V2CO2 is a promising bifunctional catalyst for water splitting (overpotentials of 0.19 and 0.37 V for HER and OER). Besides, Pt-v-V2CCl2 and Pt-v-V2CS2 possess desirable bifunctional OER/ORR activity with overpotentials of 0.49/0.55 V and 0.58/0.40 V, respectively. More interestingly, Pt-v-V2CO2 is a promising trifunctional catalyst under vacuum, implicit and explicit solvation conditions, which transcends commercially used Pt and IrO2 catalysts for HER/ORR and OER. The electronic structure analysis further demonstrates that surface functionalization can optimize the local microenvironment of the SACs and thus tune the interaction strength of intermediate adsorbates. This work provides a feasible strategy for developing advanced multifunctional electrocatalysts and enriches the application of MXene in energy conversion and storage.