化學(xué)專業(yè)外文資料翻譯--具有高靈敏度的甲醛氣體傳感器的制備及其氣敏特性-預(yù)覽頁
【正文】 ll response to alcohol and gasoline, but large response to formaldehyde gas. The response to 10 ppm formaldehyde gas is more than 80. The response is considerably larger than those recently reported for SnO2–Sb2O4,WO3–Sb2O4, NiO, and formaldehyde gas sensors [17–21]. This gas sensor showed large response to formaldehyde gas and high selectivity against alcohol and gasoline. This result indicates that the CdO–In2O3 specimen is a good gassensing material for detecting formaldehyde, which can be applied for monitoring and controlling of the formaldehyde gas. A good response and quick response/recovery time were observed with this sensor at the optimal operating temperature of 95 .C. The response changes of the gas sensor to different formaldehyde gas concentrations (10–100 ppm) are shown in Fig. 5. As a highly sensitive sensor, it can measure very low concentrations, even 10 ppm. The output voltage increases in a linear relation to the formaldehyde gas concentration with a short response time. Response time and recovery time (defined as the time required to reach 90% of the final equilibrium value) was 2 min and the recovery time was 4 min. The gassensing mechanism is based on the changes in conductance of the CdO–In2O3 material. The oxygen adsorbed on the surface of the material influences the conductance of the CdO–In2O3 sensor. The oxygen adsorption depends on the particle size, large specific area of the material, and the operating temperature of the sensor [22]. With the increasing temperature in air, the state of oxygen adsorbed on the surface of the CdO–In2O3 material undergoes the following Fig. 3. The effects of operating temperature on the sensor response to 100 ppm formaldehyde. increasing concentrations operated at an operating temperature of The oxygen species capture electrons from the material, leading to an increase in hole concentration and a decrease in electron concentration. When the sensor is exposed to formaldehyde gas, the electrons trapped by the adsorptive states will be released, leading to a decrease in sensor resistance. So, the CdO–In2O3 sensor is — 45 — sensitive to reducing formaldehyde gas. The sensors have good stabilities (no shown data). The stability mechanism is more plicated and further work is to be done to get a definite understanding. 4. Conclusion Preparation of the CdO–In2O3 specimen used as a sensing material to formaldehyde has been shown to be feasible by the solidstate synthesis technologies. The fabricated sensor showed large response magnitude, high selectivity, quick responses, and good recovery to formaldehyde gas at a low operating temperature (95 .C). The experimental results indicate the potential of using CdOmixed In2O3 material for formaldehyde gas sensing. Acknowledgements This work was supported by National Natural Science Foundation of China (No. 50662020), and Natural Science Foundation of Yunnan Province, China (No. 2020E0013M).
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