UV light-activated Eu/ZnO flower-like microsphere for detecting NO2 gas with high response

In this work, the ZnO microsphere is prepared by hydrothermal method and modified with different concentrations of Eu. The morphology of ZnO:Eu sample shows flower-like microspheres with many nanosheets. The gas performance of ZnO:Eu microsphere is investigated for detecting NO 2 . Compared with pure ZnO, the response of ZnO:2 % Eu sensor is increased by 8 times, and the optimal operating temperature of that is decreased to 130 °C. Especially, the gas sensing properties of ZnO:2 % Eu sensor is enhanced under UV excitation. The recovery time of ZnO:Eu sensor is reduced by 1200 s, and the response is increased by 3.6 times under UV excitation. The above results show an increase in sensor response due to doping Eu and UV excitation. At last, the possible gas mechanism of ZnO:Eu is discussed with and without UV excitation. This finding provides important guidance for UV-assisted sensors to enhance NO 2 response.