Sp-hybridized carbon- facilitated peroxymonosulfate activation for superior phenolic pollutant removal

Carbocatalysts, widely regarded as eco-friendly catalysts in the field of peroxymonosulfate (PMS) activation for pollutant removal, exhibit significant variations in performance depending on the type of carbon atom hybridization. Notably, the novel graphdiyne (GDY), characterized by its sp-hybridized carbon (sp-C), has recently garnered significant attention. However, the precise mechanistic role of sp-C on PMS activation remains unclear. Herein, we elucidate the role of sp-C on PMS activation and the corresponding mechanism behind enhanced phenolic pollutant degradation over the GDY catalyst. GDY demonstrates exceptional phenolic removal efficiency (97 %), which far exceeds that of traditional sp²-hybridized graphene (2 %). The GDY facilitates pollutant oxidation via a catalyst-mediated electron transfer mechanism. The sp-C provides additional sites for PMS adsorption and donates significantly more electrons from GDY to PMS (0.51 e more than graphene), effectively facilitating PMS activation, intermediate species conversion, and reaction kinetics during phenolic pollutant degradation. By integrating the monolithic GDY catalyst into a flow-through device for continuous phenolic pollutant removal, long-lasting phenolic removal was maintained for over 80 hours, with a removal rate exceeding 85 %. This work highlights that sp-C in GDY effectively enhances PMS activation, providing a pathway for efficient organic pollutant degradation in advanced oxidation processes.