Electronic structure modulation and peroxymonosulfate activation mechanism of N-doped MnCo2O4: A study on the efficient catalytic degradation of sulfamethoxazole

• Nitrogen-doped MnCo 2 O 4 catalysts synthesized via urea-assisted thermal treatment. • Nitrogen doping enhances electronic structure and reactive oxygen species generation. • Oxygen vacancies and electron-rich metal sites improve PMS activation efficiency. • Achieved efficient degradation of sulfamethoxazole through enhanced catalysis. • Provides new insights into catalyst design for environmental remediation. In this study, a nitrogen-doped MnCo 2 O 4 composite material (nN-MCO) was successfully synthesized via a urea-assisted thermal treatment method and applied for the activation of peroxymonosulfate (PMS) to degrade sulfamethoxazole (SMX). By introducing metal-N (M−N) bonds, the concentration of oxygen vacancies on the catalyst surface and its electron transfer capability with PMS were significantly enhanced. Experimental characterizations demonstrated that nitrogen doping not only strengthened the covalency of the metal-O (M−O) bonds but also facilitated the formation of electron-rich metal sites through electronic rearrangement, further improving the adsorption and activation of PMS. The 2 N-MCO catalyst successfully degraded 98.0 % of SMX within 5 min and maintained a removal efficiency of 85.0 % after four consecutive cycles. The study revealed that 1 O 2 , SO 4 − , OH and O 2 − were all involved in the degradation of SMX, with 1 O 2 identified as the dominant reactive oxygen species. This work presents a simple and effective nitrogen-doping strategy for surface modification of spinel-based catalysts, enhancing the MnCo 2 O 4 composite’s electronic structure, strengthening metal–oxygen bonds, and creating electron-rich sites. These modifications promote oxygen vacancies, improve electron transfer, and enable efficient reactive oxygen species (ROS) generation, offering valuable insights and theoretical support for PMS-based oxidation processes in pollutant treatment.