Efficient degradation of formaldehyde based on DFT-screened metal-doped C 3 N 6 monolayer photocatalysts: performance evaluation and mechanistic insights.

Photocatalytic oxidation is an efficient and promising technology for reducing indoor pollution levels of formaldehyde (HCHO). However, developing efficient and low-cost photocatalysts for the removal of HCHO remains challenging due to the time-consuming and expensive nature of traditional "trial and error" and "directed research" approaches. To achieve this goal, first-principles density functional theory (DFT) calculations were conducted to high-throughput screen candidate TM-C 3 N 6 photocatalysts for high-performance degradation of HCHO. The results revealed that Zr-C 3 N 6 and Hf-C 3 N 6 in functionalizing C 3 N 6 with 28 transition metals showed excellent adsorption energy of HCHO, boosting the highly effective capture of HCHO. Meanwhile, an excellent adsorption performance mechanism was further elicited by the electric structure-property relationship. In addition, reaction mechanisms for HCHO degradation and three potential reaction pathways for HCHO degradation were systematically evaluated. Our findings indicated that hydroxyl-assisted dehydrogenation and oxygen-assisted dehydrogenation are the most favorable pathways, with rate-limiting steps involving the formation of ˙OH and ˙O radicals. Overall, this study may provide new insights into a high-throughput screening of novel photocatalysts that are both high-performing and low-cost for the removal of formaldehyde. This, in turn, can accelerate the experimental development process and reduce the associated costs and time consumption.