Converting the toxic air pollutant N 2 O into less harmful gas has potential advantages. Herein, the feasibility of the N 2 O reduction reaction over pristine C 2 N and TM/C 2 N (TM = V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) monolayers are explored by density functional theory calculations with Grimme-D3 correction. The results reveal that the existence of TM atoms indeed improves the adsorption performance of C 2 N, where the TM atoms act as both electron acceptors and donors, favoring the activation of N 2 O and CO molecules. Based on thermal stability, selectivity, and catalytic activity, TM/C 2 N (TM = V and Mn) catalysts are screened from the above transition metal atoms. In particular, N 2 O reduction is a thermodynamically and kinetically favorable pathway, which can take place with negligible energy barriers on V/C 2 N and Mn/C 2 N catalysts. The CO 2 desorption on V/C 2 N and Mn/C 2 N catalysts is the rate-limiting step with the desorption barrier of only 13.1 and 15.1 kcal mol −1 , respectively. These results suggest that the screened TM/C 2 N (TM = V and Mn) materials can be used as promising catalysts for the adsorption and reduction of environmentally unfriendly N 2 O molecules.