Enhancing singlet oxygen production of dioxygen activation on the carbon-supported rare-earth oxide nanocluster and rare-earth single atom catalyst to remove antibiotics.

Singlet oxygen (O) is extensively employed in the fields of chemical, biomedical and environmental. However, it is still a challenge to produce high- concentration O by dioxygen activation. Herein, a system of carbon-supported rare-earth oxide nanocluster and single atom catalysts (named as REO/RE-C, RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc and Y) with similar morphology, structure, and physicochemical characteristic are constructed to activate dissolved oxygen (DO) to enhance O production. The catalytic activity trends and mechanisms are revealed experimentally and are also proven by theoretical analyses and calculations. The O generation activity trend is GdO/Gd-C>ErO/Er-C>SmO/Sm-C>pristine carbon (C). More than 95.0% of common antibiotics (ciprofloxacin, ofloxacin, norfloxacin and carbamazepine) can be removed in 60 min by GdO/Gd-C. Density functional theory calculations indicate that GdO nanoclusters and Gd single atoms exhibit the moderate adsorption energy of ·O to enhance O production. This study offers a universal strategy to enhance O production in dioxygen activation for future application and reveals the natural essence of basic mechanisms of O production via rare-earth oxide nanoclusters and rare-earth single atoms.