Construction of Oxygen Vacancies of Zr-Doped CeO2 with Enhanced Dye Adsorption Performance

Congo red (CR), a highly pigmented anionic dye, is highly toxic and resistant to degradation. The discharge of CR wastewater into the natural environment can lead to ecological destruction and harm to human health. CeO2 as an adsorbent possesses the advantages of excellent acid and alkali resistance, biocompatibility, stable physical and chemical properties, and nontoxic by-products. The impact of Zr doping on the adsorption performance of nano-CeO2 was investigated. XPS and Raman characterisation revealed that Zr doping effectively enhanced the oxygen vacancy ratio at the active sites for CR adsorption on the surface of nano-CeO2. When the doping amount of Zr was 3%, the nanoparticles with the best adsorption properties were obtained, and the adsorption amount of CR at room temperature was as high as 3642.05 mg/g, which was approximately three times the adsorption amount of undoped CeO2. This excellent adsorption property shows good prospects for the removal of anionic dyes from wastewater.