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

Abstract

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 O₂ 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.