Computational screening of M-N-C single-atom sensors for multicomponent VOC detection

Volatile organic compounds (VOCs) pose serious risks to environmental safety and human health, yet their multicomponent detection remains limited by insufficient sensitivity, selectivity, and reusability. In this work, first-principles calculations were used to screen graphene-supported transition-metal single-atom M₁-N_X-C materials for detecting five representative VOCs, including CB, T, o-DCB, m-DCB, and p-DCB. Forty candidates were constructed by combining ten transition-metal centres with four nitrogen coordination environments. A multidimensional screening framework was established by integrating adsorption energy, Bader charge transfer, band gap variation, TranSIESTA transport response, and recovery time. The results show that nitrogen coordination generally enhances VOC adsorption, while the metal centre and local coordination environment jointly regulate adsorption stability, charge transfer, electronic perturbation, and desorption behaviour. Cu₁-N₃-C exhibits detectable responses toward all five VOCs and shows strong potential as a universal sensing material, whereas Ni₁-N₃-C responds to four VOCs. Co₁-N₂-C and Mn₁-N₁-C achieve faster recovery with clear electrical responses, making them suitable for repeated sensing. This work establishes a structure-property-guided screening strategy for M-N-C single-atom sensors and provides a theoretical foundation for the rational design of reusable, selective, and multicomponent VOC detection materials.