Enhanced photocatalytic activity of ZnO/La2O3 composite modified by potassium for phenol degradation

•ZnO/La2O3 composite was successfully prepared by potassium modification.•K-dopants added to the ZnO lattice improved the optical absorption.•La2O3 nanorods promote ZnO distribution and protect ZnO from agglomeration.•Synergetic effects generated by K and La2O3 account for its superior property.

K-doped ZnO/La2O3 composite photocatalyst was synthesized via facile sol–gel route using glucose as a complexing agent. The concentrations of K and La2O3 were varied, it was found that the formation of ZnO/La2O3 composite mainly lay in the promotional effect of potassium and 10 mol% content of K-doping was optimum to obtain ZnO/La2O3 composite. The results showed that, in contrast to pure ZnO and undoped ZnO/La2O3, K-doping greatly changed the microstructure, morphology, optical property and photocatalytic performance of ZnO/La2O3 composite. The photocatalytic activity of K-doped ZnO/La2O3 composite yielded 98.5% degradation of phenol solution after 2.5 h visible light irradiation, which was explained by the synergetic effect generated by the introduction of both K and La2O3.

Graphical abstractZnO/La2O3 composite modified by 10 mol% potassium was successfully prepared by the glucose sol–gel method, whose phenol degradation was 98.5% after 2.5 h visible light irradiation, which is superior to that of undoped ZnO/La2O3 and pure ZnO. The excellent activity of K-doped ZnO/La2O3 is ascribed to the synergetic effects generated by the introduction of both K and La2O3. (a) HRTEM image of K-doped ZnO/La2O3 and (b) degradation of phenol over various samples as a function of time under visible light irradiation.Figure optionsDownload full-size imageDownload as PowerPoint slide