Accelerated activation of H2O2 and persulfate by Sm-doped ZnO@highly-defective layered yttria nanocomposite under visible-light irradiation for dyeing wastewater treatment: Comprehensive dominance of oxygen vacancies in photocatalytic advanced oxidation processes

Herein, innovative visible-light-driven nano-photocatalysts for accelerated-activation of H2O2 and persulfate (PS) are explored towards degradation of ionic-dyes from wastewater. Highly-defective yttria-layers (D-Y2O3) are customized and used for stabilization of ZnO and Sm-doped ZnO (Sm-ZnO) nanoparticles. Comparing to [email protected]2O3, [email protected]2O3 nanocomposite possesses advanced surface-area and porosity with significant surface-heterogeneity, elevated negatively-charged nanoparticles (ζav = −36.3 mV), large populations of oxygen vacancies, and enhanced visible-light absorptivity. PS-activation over visible-light-driven [email protected]2O3 photocatalyst ([email protected]2O3/PS/Vis) displays superior degradation efficiency (~100 %) of isosulfan-blue, Bismarck-brown, and methylene-blue dyes within 10 min, near-complete mineralization performance, and great cyclability. Such excellent photodegradability results from (i) synergistic combination of nanocomposite-PS-visible light, yielding highly-developed synergy-index values (SI = 3–20), (ii) abundant generation of reactive-oxidizing-species (SO4•-/h+/•OH synergistic ratio 1:1.8:1.9), and (iii) facilitated transference of photoexcited-electrons across oxygen vacancies in yttria-moiety, prohibiting electron-hole pairs recombination. Hence, [email protected]2O3/PS/Vis system is an extraordinarily candidate for complete destruction of organic-pollutants via newly photocatalytic-mechanism, whatever it treats it degrades.