In this work, we have demonstrated multi walled carbon nanotubes (MWCNTs) based CO₂ gas sensor using a reliable and low cost gel-cast method with MWCNT concentration of 0.6, 1.0, 1.5, 2.0 and 3.0 by wt% in alumina Al₂O₃ sol which acts as a host matrix for the composite. Sensing response of the as prepared highly uniform self-standing MWCNTs film was measured at room temperature by exposure to different CO₂ concentrations, ranging from 50 ppm to 450 ppm. The adsorption effect of CO₂ on the varying concentration of CNTs was investigated by measuring a significant change in the resistance. Upon exposure to CO₂ molecules, the device shows a drastic increase in resistance attributed to the charge transfer between CNTs and CO₂ molecules. High sensor response of 7.3% with a response time of 53.7 s exhibited by sensor S3 (1.5 wt% of MWCNTs) is reported when the concentration of CO₂ is 450 ppm in ambient conditions. In addition, different recovery modes were examined and the results reveal that there is a significant decrease in the recovery time of sensor upon UV light exposure and heat application. Besides being fast recoverable with heat energy, the fabricated gas sensor shows favorable stability in response over multiple exposure of analyte gas.

在这项工作中，我们已经证明了使用可靠且低成本的凝胶浇铸方法，基于多壁碳纳米管（MWCNT）的CO ₂气体传感器，氧化铝Al ₂ O中的MWCNT浓度为0.6、1.0、1.5、2.0和3.0 wt％₃溶胶，用作复合材料的基质。通过暴露于50 ppm至450 ppm范围内的不同CO ₂浓度，在室温下测量所制得的高度均匀的自立式MWCNTs薄膜的传感响应。通过测量电阻的显着变化，研究了CO ₂对不同浓度的CNT的吸附效果。暴露于CO ₂由于碳纳米管和CO ₂分子之间的电荷转移，该装置显示出电阻的急剧增加。当在环境条件下CO ₂的浓度为450 ppm时，传感器S3（MWCNT的1.5 wt％）显示出7.3％的高响应速度和53.7 s的响应时间。此外，检查了不同的恢复模式，结果表明，在暴露于紫外线和加热后，传感器的恢复时间显着减少。除了可以通过热能快速恢复外，制造的气体传感器还显示出在多次暴露分析物气体时的良好稳定性。