6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Ultra-Sensitive and Energy Efficient Low-ppb NOx Gas Sensors Based on Pd-sensitized Co3O4/NiTiO3 Heterojunctions

9 Jul 2026, 12:20
20m
Lecture Hall DL3 (University of the Western Cape)

Lecture Hall DL3

University of the Western Cape

Oral Presentation Track F - Applied Physics Applied Physics

Speaker

Zamaswazi Tshabalala (University of the Free State)

Description

The widespread emission of nitrogen oxides (NOx; NO and NO2) from mining and transportation activities necessitates sensitive and reliable gas sensing technologies with low power requirements and economic feasibility for large scale deployment. Conventional NOx monitoring systems are often constrained by complex fabrication processes, costly components, and high-power consumption, limiting their applicability in resource‑constrained environments. In this study, a low‑cost, low‑power NOx gas sensor based on Ag‑ and Pd‑sensitized Co3O4/NiTiO3 semiconducting heterostructures is developed. The nanostructures were synthesized via a microwave‑assisted hydrothermal method followed by wet impregnation and subsequently drop‑cast onto interdigitated substrates to form sensing layers. This fabrication strategy provides a facile and cost‑effective synthesis, significantly reducing processing time, energy input, and equipment complexity. Gas‑sensing measurements demonstrate that Pd sensitization significantly enhances NOx sensitivity and accelerates response–recovery dynamics. Importantly, these improvements are achieved at reduced operating temperatures, resulting in substantially lower power consumption, which is an essential requirement for portable and battery‑powered applications. The combination of scalable, cost‑effective fabrication and energy‑efficient device performance highlights Pd‑sensitized Co3O4/NiTiO3 heterostructures as a promising platform for NOx monitoring, underscoring the role of interface engineering in sustainable gas‑sensor development.

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Author

Zamaswazi Tshabalala (University of the Free State)

Co-authors

Boitumelo Tladi (University of the Free State) Katlego Morulane (University of Free State) Hendrik Swart (University of the Free State) David Motaung (University of the Free State)

Presentation materials