Spatial confinement and electronic modulation of porous carbon-encapsulated Co3Mo3N coral-like architecture: Synergistically boosting peroxymonosulfate activation for robust recyclable 4-nitrophenol degradation.

Cobalt-based nitrides are promising catalysts for the activation of peroxymonosulfate (PMS). However, their catalytic efficiency and stability can be hindered by insufficient interfacial electron transfer and the deactivation of active metal centers. In this study, a bimetallic synergy strategy is employed to synthesize a highly efficient cobalt-molybdenum bimetallic nitride composite (Co3Mo3N@C) through a two-step H2/Ar annealing process. The Co3Mo3N@C/PMS system achieved a 96.0% removal efficiency of 4-nitrophenol (4-NP) within 25 min, demonstrating kinetic rate constants that are 16.6-fold and 3.2-fold higher than those of the Mo2N@C/PMS and Co4N@C/PMS systems, respectively. The enhanced catalytic performance can be primarily attributed to the wrinkled porous architecture, which exposes abundant accessible sites, and the synergistic Co-Mo electronic interaction that promotes interfacial electron transfer and redox cycling during PMS activation. Additionally, the system exhibits favorable catalytic performance across a broad pH range and under various water-matrix conditions. Mechanistic investigations reveal the coexistence of radical and non-radical oxidation pathways, along with an interfacial electron-transfer process. Furthermore, Co3Mo3N@C demonstrates good structural stability, reusability, and applicability towards different organic pollutants. These results indicate that coupling bimetallic electronic modulation with carbon confinement presents an effective strategy for designing efficient and durable PMS-activation catalysts for the remediation of organic pollutants.