Tailoring crystal quality in ZnO nanomaterials for enhanced photocatalytic performances toward removals of organic pollutants for environmental protection
摘要
In this work, the crystal quality of ZnO nanomaterials tailored in by manipulating defects in related properties, which are helpful in enhancing the photocatalytic performance. ZnO nanomaterials have been successfully prepared by a one-step hydrothermal method using only zinc acetate as the raw material for the removal of methyl blue (MB) and tetracycline (TC). The X-ray diffraction (XRD) results indicated that the ZnO-2 sample has the smallest micro-stress and the lowest dislocation density, and it possesses the highest crystal quality. Microscopic analysis results indicated that the additional amount of zinc acetate and nitrogen doping directly affects the morphology and crystal quality of ZnO nanomaterials. The photoluminescence (PL) spectra studies indicated that the high crystal quality and uniform morphology promote the effective separation of photogenerated carriers. The influence of crystal quality on the photocatalytic degradation efficiency of ZnO nanomaterials was systematically studied. Evaluation of photocatalytic activity against methylene blue and tetracycline demonstrated the superior performance of ZnO-2 catalyst, which was contributed to the high charge separation efficiency due to its higher crystal quality and uniform morphology. Notably, the photodegradation efficiency of 10 mg/L MB by the 50 mg ZnO-2 sample reached 99.2% with 30 min. The photodegradation efficiency of 20 mg/L TC by the 50 mg ZnO-2 sample reached 93.4% with 40 min. Quenching tests proved that the hydroxyl radical (•OH) and the superoxide radical