Well-defined Fe/Cu diatomic catalysts for boosted peroxymonosulfate activation to degrade organic contaminants

Abstract

The Fe-N-C catalyst with a FeNx active site has gained ever-increasing attention for peroxymonosulfate (PMS) activation to degrade organic contaminants, however, the regulation of the electronic configuration of Fe centers to further enhance the catalytic ability still remains a huge challenge. Herein, a well-defined Fe/Cu diatomic catalyst (Fe/CuDA-NC) was successfully fabricated. The Fe/CuDA-NC/PMS system can almost completely degrade sulfamethoxazole (SMX) in a wide pH range (3.0–9.0). Significantly, the degradation rate constant in Fe/CuDA-NC/PMS reaction (0.4672 min−1) was twice as high as that in Fe single-atom Fenton-like system (0.2213 min−1). Theoretical simulations illustrated that electron transfer from nearby Cu atom to Fe atom effectively optimized the bonding orbital distribution in the Fe 3d orbitals and subsequently promoted the adsorption and activation of PMS. Besides, the sulfate radicals (SO4−·), hydroxyl radicals (OH), superoxide radicals (O2–), high-valent metal-oxo species, and mediate metal-peroxo intermediates, made vital contributions to the decomposition and mineralization of SMX. We further deposited the catalysts on the widely used polyvinylidene fluoride (PVDF) microfiltration membrane and demonstrated that the target contaminants were oxidized to remove over 90 % in 60 min when passing through the filter, which showed the prospect of utilizing this novel catalyst in practical applications.