Visible‐Light‐Driven Selective Mineralization of Organohalides on Spatially Close Au Single‐Atom and Nanocluster Neighbors Over Poly(Heptazine Imides)

Organohalides are commonly found pollutants with long-term persistence in industrial wastewater and drinkable water. Although these pollutants only constitute a small portion of the total organic carbon (TOC), they contribute major toxicity, posing a threat to ecosystem, biodiversity, and public health. Selective removal of organohalides from wastewater/drinkable water is costly due to the orders of magnitude lower concentration of organohalides as compared to interferences. Herein, spatially close Au single atoms and nanoclusters composing of approximately 3-10 Au atoms were grown on highly crystalline potassium-incorporated poly(heptazine imides). Microscopy and spectroscopy characterizations together with theoretical calculations revealed that under visible-light illumination, the highly localized photogenerated holes could enable simultaneous generation of •OH on Au single atoms and selective adsorption of organohalides on Au nanoclusters, which greatly promoted the targeted removal of trace organohalides in water containing high concentrations of interferences. The fixed-bed photoreactor built using the spatially close Au single atoms and nanoclusters on poly(heptazine imides) achieved quick degradation of refractory organohalide pollutants in tap water and ground water (2 L h^-1), exhibiting an over 3-fold log efficiency enhancement compared to traditional advanced oxidation processes.