Two-dimensional MXene supported single transition metal atom for HCHO catalytic oxidation: A first-principles study combined with Microkinetics

Catalytic oxidation is an efficient and environmentally friendly strategy for the removal of pollutant HCHO. Recent proof -of -concepts experiments indicate that single -atom catalysts (SACs) exhibit good activity for HCHO catalytic degradation, but a major obstacle is to look for an effective SAC. Herein, ten 3d transition metal SACs decorated on Mo 2 CS 2 substrate were designed and constructed to catalyze HCHO using periodic density functional theory calculations. The results showed that the single atoms are inclined to locate at the Mo top site on the surface and most SACs can stay stable. Among these SCAs, Ti, V, Cr, and Mn SACs have shallow energy barriers of O 2 activation and can facilitate O 2 dissociation at room temperature. Therefore, two typical HCHO oxidation pathways on TM@Mo 2 CS 2 (TM = Ti, V, Cr, and Mn) catalyst were investigated in detail. The V@Mo 2 CS 2 has the lowest energy barrier of 1.72 eV for the rate -limiting step during HCHO oxidation via path -I (O 2 adsorption and activation, HCHO* -> CHO* -> CO* -> CO 2 *). Correlation analysis verifies that the Bader charge and O 2 adsorption are the appropriate descriptions for HCHO catalytic oxidation activity. Microkinetic simulations are further performed to reveal the relationship between HCHO oxidation rate and temperature.