Single-atom iron cocatalyst for highly enhancing TiO2 photocatalytic degradation of antibiotics and antibiotic-resistant genes

The efficient and sustainable utilization of solar energy and biomass resources through photocatalysis is important for achieving a carbon-neutral energy cycle. Here, we report an efficient photocatalyst SA-Fe@TiO2, where single -atom Fe sites are anchored to nitrogen-doped biochar and coupled with anatase TiO2. This innovative biochar-supported single -atom catalyst serves as a novel cocatalyst that can facilitate charge carrier separation and transfer. SA-Fe@TiO2 achieves an increase of 4.3 times in apparent rate constant for the degradation of the antibiotic sulfamethoxazole (SMX) and exhibits superior capacity for inactivating antibioticresistant genes compared with pure TiO2. Experimental evidence reveals the remarkable resistance of SAFe@TiO2 against environmental interferences, unveiling the involvement of three primary reactive species (h+, center dot OH, and center dot O2 ) in SMX photodegradation. In addition, we fabricate immobilized SA-Fe@TiO2 films that effectively degrade five distinct antibiotics within 20 min. This study presents a new method for developing singleatom photocatalysts for highly efficient environmental remediation in the context of carbon neutrality.