First-principles study of precise O vacancy-deficient MXene as an ORR/OER bifunctional catalyst

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 718; p. 136899
• Main Authors: Li, Hao, Xie, Kun, Shi, Pei, Wang, Chaoyang, Lin, Long, Xu, Dongxia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.08.2025
• Subjects: adsorption; catalysts; catalytic activity; Density functional theory; electrochemistry; Electronic structure; energy; MXene; oxygen; oxygen production; Oxygen reduction and oxygen evolution reaction; Density functional theory; Electronic structure; Oxygen reduction and oxygen evolution reaction; MXene
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2025.136899

The catalytic activity of MXene catalysts for oxygen reduction and oxygen evolution reaction (ORR and OER) is limited by the coordination environment of the active center. However, the mechanism of how vacancy-induced reconstruction catalysts promote ORR/OER remains unclear. Here, we exploit oxygen vacancies in Mo2CO2 to reveal the influence of defects in the reconstruction process and the limitations of active center coordination environments with different TM atom compositions on the catalytic process. Through theoretical calculations, we found that the enhanced adsorption of OOH* by the oxygen defects during the catalytic process drove the catalyst's reconstruction, especially in the OER reaction, where the presence of O vacancies somewhat breaks the linkage between OH* and the overpotential and shows excellent OER activity. It was found that the Os-OV@Mo2CO2 catalyst had the highest activity with theoretical overpotentials ηORR = 0.43 V and ηOER = 0.49 V, which were close to or better than those of conventional Pt (111) and IrO2 (110). In addition, we systematically investigated the interactions between the catalyst and the reaction intermediates during the reaction process and elucidated the relationship between the changes in the free energies of different oxygenated intermediates. Overall, this study provides a feasible approach for the design and development of advanced bifunctional electrocatalysts, enriches the application of MXene, a novel two-dimensional material, in the electrochemical energy field, and provides theoretical experience for the design of defective MXene catalysts. [Display omitted] •Oxygen-deficient MXene materials has potential for candidates as OER/ORR bifunctional catalysts.•Oxygen defects enhance the interaction of transition metal atoms with the catalyst substrate.•Os-Ov@Mo2CO2 Oxygen Vacancy Coordination Breaks ηOER-∆GOH* Linearity.•Electronic Structure and Catalytic Mechanism of MXene-Based Transition Metal SACs.