Enhanced CO2 gas-sensing performance of ZnO nanopowder by La loaded during simple hydrothermal method

The use of semiconducting metal oxides to develop highly sensitive CO2 chemi-resistive sensing systems remains an important scientific challenge in the field of gas sensing. In this work, we describe the synthesis, characterization, and application of a very important CO2 gas sensing material ZnO-loaded with different atomic percentages of La prepared by a simple hydrothermal method. Synthesized samples were structurally and thermally characterized. The CO2 sensing characteristics of pure ZnO and La-loaded ZnO were compared using a homemade gas sensing measurement system. The sensitivity, operating temperature, and response/recovery time were systematically investigated based on the change in electrical resistance of the materials in the presence of CO2. Experimental results confirmed that 50 at% La-loaded ZnO showed a maximum response to 5000 ppm CO2 (65%) at an operating temperature of 400 °C. The sensing mechanism of the pure and La-loaded ZnO nanopowders is discussed in detail. We believed that the La-loaded, flower-like ZnO nanopowder offers a potential platform for semiconductor-oxide-based CO2 gas sensors.