Unveiling the mechanism of thermal catalytic oxidation of HCHO from the kiln exhaust gas using Sc-decorated Cr₂CO₂-MXenes

HCHO is one of the volatile organic compounds (VOCs), whose toxicity and volatility have a significant effect on health and the environment. In this study, Sc/Cr2CO2 as a single-atom catalyst was investigated for the oxidation of HCHO using thermal catalysis and density functional theory (DFT). Sc/Cr2CO2 shows excellent thermal stability as revealed from ab initio molecular dynamic (AIMD) simulations. With an increase in temperature, the adsorption of O-2 and HCHO on Sc/Cr2CO2 is enhanced. The results of Gibbs free energy indicate that the catalytic reactivity of Sc/Cr2CO2 is enhanced for HCHO when temperature is increased. For the dissociation of O-H bonds, the diffusion barriers of high temperature (448 K) are lower than those of room temperature (298 K) at the Eley-Rideal (ER) path, which indicates that the reaction can be promoted for the ER path at high temperatures. Thus, Sc/Cr2CO2 can be a promising high-temperature HCHO oxidation candidate. This work may pave the way for the next generation of advanced catalytic materials for high-efficiency catalytic HCHO oxidation with the kiln exhaust gas.