Tailoring crystal quality in ZnO nanomaterials for enhanced photocatalyic performances toward removals organic pollutants for environmental protection

In this work, the crystal quality tailored in ZnO nanomaterials that manipulated defects in related properties, which are helpful in enhancing the photocatalytic performance. ZnO nanomaterials have been successfully prepared by one-step hydrothermal method using only zinc acetate as the raw material for the efficient removal of methyl blue and tetracycline under simulated sunlight irradiation. The 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. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results indicated that the addition amount of zinc acetate and nitrogen doping directly affect 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 charge 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 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, under 30 minutes simulated sunlight exposure, the photodegradation efficiency of 10mg/L methyl blue by the 50mg ZnO-2 sample reached 99.2%. under 40 minutes simulated sunlight exposure, the photodegradation efficiency of 20mg/L tetracycline by the 50mg ZnO-2 sample reached 93.4%. Quenching tests proved that the hydroxyl radical (•OH) and the superoxide radical (\(\:{\text{O}}_{2}^{{\bullet\:}-}\)) played main role in the photodegradation of methylene blue and tetracycline under simulated sunlight irradiation. This research underscores the potential of ZnO-2 as a promising photocatalyst, offering stability, reusability, and effective utilization of sunlight for catalytic processes.