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Nitrogen dioxide (NO2) is a very hazardous gas to human health that requires specialized detection at low temperatures for environmental monitoring. This study investigated synthesized rare-earth (RE)-doped CuO/ZrO2 p-n heterostructures doped with various concentrations (0.5-1%) of Ho3⁺ and Yb3⁺ ions via a hydrolysis process and their applications for gas sensing. X-ray powder diffraction (XRPD) analysis revealed monoclinic CuO and tetragonal ZrO2 phases, with no secondary impurities, indicating good phase purity. The crystallite size decreased, accompanied by increased lattice strain and dislocation density, indicating the formation of more defect-induced active sites with increasing RE doping. Surface morphology analyses revealed triangular nanoplatelets and prism-like nanostructures. Optical studies demonstrated that the introduction of RE led to increased surface defects, associated with oxygen vacancies and defect-related transitions, suggesting altered charge-carrier dynamics. The sensing analyses demonstrated that among the materials, the 0.5 wt.% Yb-CuO/ZrO2 disclosed improved NO2 detection. The improved sensing performance is due to the formation of the CuO/ZrO2 p-n heterojunction, increased defect density, enhanced surface adsorption, and improved charge transfer resulting from RE doping. These findings showed that RE-doped CuO/ZrO2 heterostructures are a promising candidate for efficient, selective, and low-temperature NO2 gas detection.
Keywords: CuO/ZrO2, p-n heterostructure, rare earth doping, NO2 sensing.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |