Investigation of Methane Gas Sensing Performance of CuO Pallets Synthesized via Co-precipitation Method

Methane (CH₄) is a widely used gas for the domestic and industrial application, which makes it a prominent fuel for us in daily life. The lower explosive limit of CH₄ is 4.9% which makes this gas dangerous. Working with this gas without knowing its concentration in any confined space is much dangerous, so its sensing and monitoring is necessary. Mostly, n-type materials such as ZnO and SnO₂ are frequently reported for CH₄ sensing. In this work, we have synthesized p-type nanostructures, i.e., CuO using co-precipitation method. Synthesized CuO nanostructures were characterized through the XRD, Raman scattering, FESEM, EDX, and KEITHLEY semiconductor characterization system. Synthesized nano-powder was compressed as a pallet, and silver conductive paste was pasted on each pallet for electrical measurement. In this work, we have developed a highly responsive and energy-efficient p-type sensor, and sensing capability of this sensor, i.e., CuO toward methane gas, was investigated at different operating temperatures, i.e., 250, 300, and 350 °C. Sensitivity (%) at different working temperatures was 34, 38, and 42%, respectively. Maximum sensitivity (%) was evaluated at 350 °C and was found 42%. CuO sensor worked in the temperature range of 250–350 °C. Beyond this temperature limit, again a decrease in response was noted. These results demonstrated the potential of CuO nanostructures for fabricating low-cost, energy-efficient, and high-performance methane gas sensor.