In-situ functionalized carbon nitride membrane for ultra-efficient non-radical Fenton-like catalysis: The critical role of interlayer confinement for singlet oxygen generation

Functionalized carbon nitride membrane was designed within the interlayer nanochannels. • Pseudo-first-order kinetics constant for Co@2D CN membrane/PMS system reached 0.24 ms −1 . • Interlayer confinement modulated PMS activation promote generation of SO 5 ●– and produce 1 O 2 . • Membrane-based interlayer confinement addressed reaction selectivity in Fenton-like catalysis. Heterogeneous Fenton-like catalysis is a promising approach for wastewater treatment but is constrained by mass transport limitations and poor reaction selectivity. To address these challenges, an in-situ functionalized membrane with active cobalt modification on a two-dimensional carbon nitride (2D CN) substrate (Co@2D CN membrane) was designed and applied to activate peroxymonosulfate (PMS) and remove emerging organic contaminants under continuous-flow conditions. The in-situ functionalization strategy preserved the interlayer nanochannels of the 2D membrane and ensured uniform cobalt dispersion, thereby providing an efficient platform for non-radical Fenton-like catalysis under interlayer confinement. Mechanistic analysis revealed that interlayer confinement enhanced singlet oxygen ( 1 O 2 ) production by promoting electron transfer between cobalt sites and PMS to form SO 5 ●– precursors. Furthermore, density functional theory (DFT) calculations demonstrated that interlayer confinement tailored PMS adsorption and molecular configuration, facilitated electron transfer between Co sites and PMS, and lowered thermodynamic barriers of PMS activation, which accelerated the self-reaction of SO 5 ●– precursors and boosted 1 O 2 evolution. With distinctive unoccupied π* orbitals, long lifespan and selective oxidation properties, 1 O 2 greatly mitigated the interference of coexisting anions and natural organic matter (NOM). This work demonstrates that interlayer confinement efficiently promotes selective 1 O 2 production, offering a promising strategy for membrane-based nonradical Fenton-like catalysis toward practical wastewater remediation. Download: Download high-res image (312KB) Download: Download full-size image