Nanostructured Spin Ladder Compound CaCu_2O_3 based Gas Sensor for the Detection of Volatile Organic Compounds

摘要

Several volatile organic compounds (VOCs) are found in human breath and the concentrations of such VOCs are usually measured to be at sub-ppm level or even lower for healthy human beings. Abnormal concentrations of the breath VOCs are reported to correlate with unhealthy/injurious body/organ conditions; for instance, acetone gas for diabetes, trimethylamine for uremic patients and ammonia gas for renal disease. Hence, VOCs can potentially be used as disease-specific biomarkers for non-invasive early detection or monitoring from breath. Acetone can be produced via the fatty acid oxidation in diabetes and ketoacidosis lack of insulin. Excessive acetone circulating in the blood system is excreted from the lungs. Higher acetone concentration ranges from 1.7 ppm to 3.7 ppm could be detected in breath for those who are diabetic, while the breath of healthy human typically contains less than 0.8 ppm. Gas sensors with sub-ppm acetone detection capacity play an important role in the development of non-invasive monitors or early diagnosis of potential diabetic patients. Up to date, various gas sensors have been successfully developed to detect acetone by controlling the morphology of nanomaterials or introducing the noble metals into nanoparticles. Although, these sensors had achieved the purpose to detect acetone gas, the high operating temperature, higher-energy cost, and the long response time still limit their further applications in practice. Great effort has been made to improve that, by choosing novel material. In order to solve these problems, the present work will focus on the design and development of gas sensors based on new nanomaterials CaCu_2O_3 offer extremely large surface-to-volume ratio, and the possibility to modify their surface reactivity to attain high sensitivity at low concentration (ppt or lower) required for detection of acetone.