Ajay Agarwal

Bio: Ajay Agarwal is an academic researcher from Birla Institute of Technology and Science. The author has contributed to research in topics: Operating temperature & Thermal oxidation. The author has an hindex of 1, co-authored 1 publications receiving 2 citations.

CO Gas-Sensing at Low Temperature using CuO Thin Films

Abstract: Carbon monoxide (CO) is known as a silent killer, as breathing in CO gas ambient for long periods with a concentration above the tolerance limit can cause severe health hazards and even death. CO concentration as low as 30 ppm (parts per million) inhaling for few hours can significantly affects the human health. This work focuses on CO gas sensing behaviors of cupric oxide (CuO) nanostructures at relatively lower operating temperature (150°C). The sensors show significant sensitivity for 25 ppm CO gas with fast response and recovery times as well as good reproducibility. Firstly, thin copper films are vacuum deposited on glass substrates at room temperature. Afterwards, these films are thermally oxidized in air, using simple thermal oxidation technique. CO sensing properties of CuO thin film are evaluated for different operating temperatures (150-250°C) and concentrations. The CuO nanostructure shows the maximum CO sensitivity for an operating temperature of 230°C. However, CO response increases with the CO concentration, which is finally saturates for a particular operating temperature.

Gas sensing behavior of Cu2O and CuO/Cu2O composite nanowires synthesized by template-assisted electrodeposition

Abstract: Metal oxide-based conductometric gas sensors are one of the promising candidates for highly sensitive, harsh environment resilient, low cost and nontoxic sensors for industrial applications. Here we present conductometric gas sensors based on Cu2O and CuO/Cu2O composite nanowires investigated towards few VOCs and CO gases. The Cu2O nanowires with an average length of 8 µm and diameter of 180 nm were synthesized through template-assisted electrodeposition of Cu2O into a polycarbonate membrane pores, from an aqueous solution. The CuO/Cu2O composite nanowires were obtained by annealing the synthesized Cu2O nanowires in an oxygen environment. The morphology, dimension, and crystallography of the synthesized nanowires are studied using scanning electron microscopy and X-ray diffraction measurements before and after annealing process. Our proposed sensor based on Cu2O nanowires showed a fast response in sensing ethanol gas at 250 °C response values of 178 and 15% towards 50 and 1 ppm of ethanol, respectively. CuO/Cu2O nanowires behaved selective and sensitive at 150 °C with a response value of 55% towards 500 ppm of CO.