Underpinning the Interaction between NO2 and CuO Nanoplatelets at Room Temperature by Tailoring Synthesis Reaction Base and Time

Dina N Oosthuizen; David E Motaung; André M Strydom; Hendrik C Swart

doi:10.1021/acsomega.9b01882

Underpinning the Interaction between NO₂ and CuO Nanoplatelets at Room Temperature by Tailoring Synthesis Reaction Base and Time

ACS Omega. 2019 Oct 23;4(19):18035-18048. doi: 10.1021/acsomega.9b01882. eCollection 2019 Nov 5.

Authors

Dina N Oosthuizen^{1

2}, David E Motaung^{1

3}, André M Strydom⁴, Hendrik C Swart¹

Affiliations

¹ Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300, South Africa.
² DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific Industrial Research, Pretoria 0001, South Africa.
³ Department of Physics, University of Limpopo, Private Bag X1106, Sovenga 0727, South Africa.
⁴ Highly Correlated Matter Research Group, Department of Physics, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa.

Abstract

An approach to tailor the morphology and sensing characteristics of CuO nanoplatelets for selective detection of NO₂ gas is of great significance and an important step toward achieving the challenge of improving air quality and in assuring the safety of mining operations. As a result, in this study, we report on the NO₂ room temperature gas-sensing characteristics of CuO nanoplatelets and the underlying mechanism toward the gas-sensing performance by altering the synthesis reaction base and time. High sensitivity of ∼40 ppm^-1 to NO₂ gas at room temperature has been realized for gas sensors fabricated from CuO nanoplatelets, using NaOH as base for reaction times of 45 and 60 min, respectively at 75 °C. In both cases, the crystallite size, surface area, and hole concentration of the respective materials influenced the selectivity and sensitivity of the NO₂ gas sensors. The mechanism underpinning the superior NO₂ gas sensing are thoroughly discussed in terms of the crystallite size, hole concentration, and surface area as active sites for gas adsorption.