Mn Doping–Induced Enhancement of Ethanol Gas Sensitivity in CuO/Cu₂O/Cu Composites

Year : 2026 | Volume : 16 | Issue : 01 | Page : 52 61
    By

    P. Samarasekara*,

  • D.P. Gunathilake,

  • D.M.S.N. Kolugala,

  • P.G.D.C.K. Karunarathna,

  1. Senior Professor, Department of Physics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka
  2. Research assistant, Department of Physics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka
  3. Research assistant, Department of Physics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka
  4. Senior Lecturer, Department of Nano Science Technology, Faculty of Technology, Wayamba, University of Sri Lanka, Kuliyapitiya, Sri Lanka

Abstract

A composite of CuO/Cu2O/Cu was synthesized by heating cupric acetate up to 600 °C for 2 hours in air. The properties of pure CuO films and CuO/Cu2O/Cu films were compared. Films were fabricated by the doctor blade method. Polyethylene glycol was used as a binder to prepare films. Mn was doped to composite to enhance the gas sensing properties. Compositions of Mn doped samples were confirmed using XRFS. According to XRD patterns, no peaks of Mn were actually observed in the composition, implying that Mn was successfully doped in the composite. Although there was a negligible trace amount of Cu in the composite, the ratio between amounts of CuO and Cu2O was nearly one. According to UV-Vis absorption spectra, the composite prefers to absorb lower energy photons. The gas sensitivity of the sample was measured at 400 ppm of ethanol at room temperature. The gas sensitivity of composite films at ethanol is higher than that of pure CuO. However, the variation of resistance after adsorbing ethanol behaves in opposite ways in pure CuO and composite. The gas sensitivity of the composite gradually increased from 45% to 107% with doping of Mn up to 6% of Mn. These improvements are attributed to the formation of CuO/Cu2O heterojunctions and Mn-induced defect states, which increase carrier concentration and active adsorption sites. Enhanced charge transfer and oxygen vacancy density facilitate room-temperature operation, faster response–recovery dynamics, and improved selectivity, indicating the composite’s promise for low-power ethanol sensing applications with good stability and reproducibility.

Keywords: CuO/Cu₂O/Cu composite, ethanol vapor, gas sensitivity, Mn doping, UV-Vis absorption

[This article belongs to Journal of Materials & Metallurgical Engineering ]

How to cite this article:
P. Samarasekara*, D.P. Gunathilake, D.M.S.N. Kolugala, P.G.D.C.K. Karunarathna. Mn Doping–Induced Enhancement of Ethanol Gas Sensitivity in CuO/Cu₂O/Cu Composites. Journal of Materials & Metallurgical Engineering. 2026; 16(01):52-61.
How to cite this URL:
P. Samarasekara*, D.P. Gunathilake, D.M.S.N. Kolugala, P.G.D.C.K. Karunarathna. Mn Doping–Induced Enhancement of Ethanol Gas Sensitivity in CuO/Cu₂O/Cu Composites. Journal of Materials & Metallurgical Engineering. 2026; 16(01):52-61. Available from: https://journals.stmjournals.com/jomme/article=2026/view=239500


References

  1. Zappa D, Comini E, Sberveglieri G. Gas-sensing properties of thermally-oxidized metal oxide nanowires. Procedia Engineering. 2012 Jan 1;47:430–3.
  2. Park S, Kim S, Sun GJ, In Lee W, Kim KK, Lee C. Fabrication and NO₂ gas sensing performance of TeO₂-core/CuO-shell heterostructure nanorod sensors. Nanoscale Research Letters. 2014 Nov 27;9(1):638.
  3. Umar A, Alshahrani AA, Algarni H, Kumar R. CuO nanosheets as potential scaffolds for gas sensing applications. Sensors and Actuators B: Chemical. 2017 Oct 1;250:24–31.
  4. Li Y, Liang J, Tao Z, Chen J. CuO particles and plates: synthesis and gas-sensor application. Materials Research Bulletin. 2008 Aug 4;43(8–9):2380–5.
  5. Bari RH, Patil SB, Bari AR. Spray-pyrolized nanostructured CuO thin films for H₂S gas sensor. International Nano Letters. 2013 Dec;3(1):12.
  6. Samarasekara P, Yapa NU. Effect of sputtering conditions on the gas sensitivity of Copper Oxide thin films. Sri Lankan Journal of Physics. 2007 Nov 11;8(21-27)
  7. Deng S, Tjoa V, Fan HM, Tan HR, Sayle DC, Olivo M, Mhaisalkar S, Wei J, Sow CH. Reduced graphene oxide conjugated Cu₂O nanowire mesocrystals for high-performance NO₂ gas sensor. Journal of the American Chemical Society. 2012 Mar 14;134(10):4905–17.
  8. Wang N, Tao W, Gong X, Zhao L, Wang T, Zhao L, Liu F, Liu X, Sun P, Lu G. Highly sensitive and selective NO₂ gas sensor fabricated from Cu₂O–CuO microflowers. Sensors and Actuators B: Chemical. 2022 Jul 1;362:131803.
  9. Sui Y, Zeng Y, Zheng W, Liu B, Zou B, Yang H. Synthesis of polyhedron hollow structure Cu₂O and their gas-sensing properties. Sensors and Actuators B: Chemical. 2012 Aug 1;171:135–40.
  10. Meng FN, Di XP, Dong HW, Zhang Y, Zhu CL, Li C, Chen YJ. Ppb H₂S gas sensing characteristics of Cu₂O/CuO sub-microspheres at low-temperature. Sensors and Actuators B: Chemical. 2013 Jun 1;182:197–204
  11. Zhao K, Li X, Tang J, Yang H, Wu Q, Wang X, Guo X, Zeng D. Effect of exposed facet determined the room-temperature ammonia gas sensing of Cu₂O nanoparticles. Applied Surface Science. 2023 Mar 15;613:156008.
  12. Mikami K, Kido Y, Akaishi Y, Quitain A, Kida T. Synthesis of Cu₂O/CuO nanocrystals and their application to H₂S sensing. Sensors. 2019 Jan 8;19(1):211 [1-14]
  13. Chandrasekar M, Subash M, Logambal S, Udhayakumar G, Uthrakumar R, Inmozhi C, Al-Onazi WA, Al-Mohaimeed AM, Chen TW, Kanimozhi K. Synthesis and characterization studies of pure and Ni doped CuO nanoparticles by hydrothermal method. Journal of King Saud University-Science. 2022 Apr 1;34(3):101831.
  14. Abd-Elkader OH, Deraz NM. Synthesis and characterization of new copper based nanocomposite. International Journal of Electrochemical Science. 2013 Jun 1;8(6):8614–22.
  15. Wang P, Gong CH, Tang AY, Gu AT, Chen KW, Yi Y. Cu-BTC derived CuO and CuO/Cu₂O composite: efficient adsorption material to iodide ions. Materials Research Express. 2023 Feb 20;10(2):025005.
  16. Bilgin VI, Kose S, Atay FE, Akyuz I. The effect of substrate temperature on the structural and some physical properties of ultrasonically sprayed CdS films. Materials Chemistry and Physics. 2005 Nov 15;94(1):103–8.
  17. Rathinamala I, Pandiarajan J, Jeyakumaran N, Prithivikumaran N. Synthesis and physical properties of nanocrystalline CdS thin films-influence of sol aging time & annealing temperature. International Journal of Thin Films Science and Technology. 2014;3(3):113–20.
  18. Muheddin DQ, Aziz SB, Mohammed PA. Variation in the optical properties of PEO-based composites via a green metal complex: macroscopic measurements to explain microscopic quantum transport from the valence band to the conduction band. Polymers. 2023 Feb 2;15(3):771
  19. Ahmed MA, Mahmoud SA, Mohamed AA. Interfacially engineered metal oxide nanocomposites for enhanced photocatalytic degradation of pollutants and energy applications. RSC Advances. 2025;15(20):15561–603.
  20. Cretu V, Postica V, Ababii N, Magariu N, Sontea V, Schütt F, Adelung R, Lupan O. Effect of dopant on selectivity of CuO nanostructured films–Based sensors. In3rd International Conference on Nanotechnologies and Biomedical Engineering: ICNBME-2015, September 23-26, 2015, Chisinau, Republic of Moldova 2016 Jan 8 (pp. 349-352). Singapore: Springer Singapore.
  21. Hsu CL, Tsai JY, Hsueh TJ. Ethanol gas and humidity sensors of CuO/Cu₂O composite nanowires based on a Cu through-silicon via approach. Sensors and Actuators B: Chemical. 2016 Mar 1;224:95–102.
  22. Maier C, Egger L, Köck A, Becker S, Niehaus JS, Reichmann K. Investigation of Gas Sensing Performance of CuO/Cu₂O Thin Films as a Function of Au-NP Size for CO, CO₂, and Hydrocarbons Mixtures. Nanomaterials. 2025 May 8;15(10):705.
  23. Rajapaksha RM, Samarasekara P, Karunarathna PG, Fernando CA. Improvement of gas sensitivity of ferric oxide thin films by adding Mn nanoparticles. Bulletin of Materials Science. 2021 Sep;44(3):182.
Regular Issue Subscription Original Research
Volume 16
Issue 01
Received 20/01/2026
Accepted 28/01/2026
Published 22/02/2026
Publication Time 33 Days
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