Author ORCID Identifier
0009-0000-1423-7904
Biosketch
I am specialized in the development and research of chemiresistive and electrochemical-based gas sensors. With a passion for advancing sensor technologies, my work focuses on enhancing detection capabilities for various applications, including environmental monitoring and industrial safety. Through rigorous experimentation and analysis, I aim to contribute to the advancement of sensor technology, addressing real-world challenges with innovative solutions. Join me on this journey towards creating a safer and more sustainable future through cutting-edge research in gas sensing technologies.
Date of Award
19-11-2025
Document Type
Thesis
School
School of Electrical & Electroncis Engineering
Programme
Ph.D.-Doctoral of Philosophy
First Advisor
Dr.B.G.Jeyaprakash
Keywords
CuO Nanograin, Ethanol Detection, Chemiresistive Sensing, CuO Based Electrodes, Spray Pyrolysis
Abstract
This study centers on the development of nanostructured sensing elements and electrochemical electrodes based on p-type CuO for ethanol detection, with a specific focus on application related onto targeting Breath and Blood Alcohol Content (BAC) monitoring. CuO nanostructures were deposited onto ceramic tubes via spray pyrolysis under optimized conditions to ensure uniform film formation. The CuO surfaces were subsequently functionalized with silver (Ag) nanoparticles via thermal evaporation and reduced graphene oxide (rGO) using the doctor blade method. Structural, morphological, and compositional analyses were conducted using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and X-ray Photoelectron Spectroscopy (XPS), respectively. Vapour sensing studies of the fabricated elements were performed in a custom-built sensing chamber.
Electrochemical properties were assessed using a 910 PSTAT mini electrochemical workstation. The bare CuO sensors exhibited a notable response to ethanol at an operating temperature of 350 °C, with a response time of 24 s and a recovery time of 35 s for 100 ppm ethanol. Ag-functionalized CuO sensors demonstrated significantly enhanced selectivity and much faster response (10 s) and recovery (11 s) times at the same temperature, attributed to the catalytic role of Ag in facilitating ethanol oxidation. In contrast, rGO/CuO sensors showed improved performance at a lower operating temperature (300 °C), with response and recovery times of 24 s and 31 s, respectively. This improvement is attributed to the synergistic interaction between CuO and rGO, which promotes enhanced charge transfer and increased surface adsorption.
The sensing elements were further evaluated in a mixed vapour environment containing common interfering vapours in exhaled breath, including acetone, methanol, ammonia, and formaldehyde (each at 50 ppm). The functionalized sensing materials demonstrated a superior selective response toward ethanol, even in the presence of these interfering vapours. To support the experimental findings, Density Functional Theory (DFT) simulations were conducted to explore the electronic structure changes of pristine CuO, Ag/CuO, and rGO/CuO upon ethanol adsorption. The simulations revealed significant alterations in the electronic structure, validating the experimental findings and confirming ethanol’s interaction at the atomic level. Electrocatalytic oxidation of ethanol in 0.5 M NaOH was systematically evaluated using cyclic voltammetry (CV) with in a potential window of –0.1 V to 0.2 V.
Modified electrodes (CuO/ITO, Ag/CuO/ITO, and rGO/CuO/ITO) displayed superior catalytic performance compared to commercial electrodes (GCE, ITO, Pt, Gr, and SPE). In particular, Ag/CuO and rGO/CuO electrodes showed higher oxidation peak currents, lower onset potentials, and enhanced long-term stability across varying ethanol concentrations (oxidation peaks ranging from –0.2 V to 2.0 V) which can be ascribed to their enlarged electrochemically active surface area and the synergistic effects of functionalization.
Recommended Citation
B, Reyoun Frances Mr, "Copper Oxide Based p-type Chemiresistive Sensing Element and Electrochemical Electrode for Ethanol Detection Application" (2025). Theses and Dissertations. 171.
https://knowledgeconnect.sastra.edu/theses/171