Visible Light-Driven High-Entropy Narrow Band Gap (Y<sub>0.2</sub>La<sub>0.2</sub>Tb<sub>0.2</sub>Dy<sub>0.2</sub>Ho<sub>0.2</sub>)MnO<sub>3</sub> Photocatalyst: Structural Characterization, Selective Removal, DFT Calculation, and Photocatalytic Mechanism
Abstract
A (Y0.2La0.2Tb0.2Dy0.2Ho0.2)MnO3 (A5MnO3) high-entropy oxide was prepared by a simple polyacrylamide gel method and the addition of Y, La, Tb, Dy, and Ho elements in an equal molar ratio to the position of the Y element of YMnO3. The high-entropy A5MnO3 catalyst exhibits a high selectivity for degrading −C═O, −NH2, and −OH bonds, as demonstrated by the results. When the catalyst content and initial contaminant concentration were 1 g/L and 50 mg/L, respectively, the degradation percentages of tetracycline hydrochloride (TC) at pH 6.4 and doxycycline hydrochloride (DOX) at pH 3.8 by the A5MnO3 catalyst reached 77.33% and 90.86%, respectively. Using TC as a representative, the degradation pathway of TC degraded by an A5MnO3 catalyst and the toxicity of the intermediate were studied by using LC-MS and toxicity assessment software. First-principles calculation determined that the A5MnO3 catalyst is a narrow band gap semiconductor. The results confirmed that hole, hydroxyl, and superoxide radicals are the main active species of the A5MnO3 catalysts for the degradation of pollutants. A novel strategy and technical guidance are presented in this study to synthesize novel narrow band gap high-entropy oxides that can degrade pollutants in wastewater.