Fabrication of porous Cl-Nb2O5-x nanostructures with large surface areas for photodegradation of organic contaminant: Morphology evolution, performance, and mechanism

Fabricating semiconductor photocatalysts with abundant oxygen vacancies and porous structures contributes to charge separation and surface photocatalytic degradation reactions. In this work, porous Cl-Nb₂O_5-x nanostructures were synthesized via a calcination method using NbCl₅ as the niobium and chlorine sources to achieve efficient tetracycline degradation under visible-light irradiation. Porous Nb₂O_5-x nanostructures were formed during the calcination process accompanied by the generation of oxygen vacancies. The obtained Cl-Nb₂O_5-x samples demonstrated significantly enhanced photocatalytic performance compared to commercial Nb₂O₅. The synthesized Cl-Nb₂O_5-x-450 sample exhibited the highest photocatalytic performance, achieving a maximal rate constant of 0.03093 min⁻¹, which markedly surpassed that of commercial Nb₂O₅. The remarkable enhancement in tetracycline degradation of the Cl-Nb₂O_5-x photocatalysts was mainly attributed to the generation of oxygen vacancies and porous structures with large surface areas. Finally, the photodegradation pathways of tetracycline facilitated by the Cl-Nb₂O_5-x photocatalysts and a plausible photocatalytic mechanism of the Cl-Nb₂O_5-x photocatalysts were also investigated in this work.