Density functional theory-based screening of Ti₄C₃O₂-loaded single atoms for efficient selective catalytic oxidation...

Indoor formaldehyde (HCHO) pollution poses a major risk to human health. Low-temperature catalytic oxidation is an effective method for HCHO removal. The high activity and selectivity of single atomic catalysts provide a possibility for the development of efficient non-precious metal catalysts. In this study, the most stable single-atom catalyst Ti-Ti₄C₃O₂ was screened by density functional theory among many single atomic catalysts with two-dimensional (2D) monolayer Ti₄C₃O₂ as the support. The computational results show that Ti-Ti₄C₃O₂ is highly selective to HCHO and O₂ in complex environments. The HCHO oxidation reaction pathways are proposed based on the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. According to the reaction energy and energy span models, the E-R mechanism has a lower maximum energy barrier and higher catalytic efficiency than the L-H mechanism. In addition, the stability of the Ti-Ti₄C₃O₂ structure and active center was verified by diffusion energy barrier and ab initio molecular dynamics simulations. The above results indicate that Ti-Ti₄C₃O₂ is a promising non-precious metal catalyst. The present study provides detailed theoretical insights into the catalytic oxidation of HCHO by Ti-Ti₄C₃O₂, as well as an idea for the development of efficient non-precious metal catalysts based on 2D materials.