6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Enhanced toluene detection using Ag-functionalized high surface area Cr2O3@SnO2 core–shell heterostructure-based gas sensor

8 Jul 2026, 16:20
1h 20m
Great Hall ( University of the Western Cape)

Great Hall

University of the Western Cape

Poster Presentation Track A - Physics of Condensed Matter and Materials Poster Session 2

Speaker

Kholofelo Mohloishane Seloane (University of the Free State, Physics Department)

Description

The development of highly selective and low-temperature gas sensors remains an imperative challenge for air quality monitoring and industrial safety. The toxicity and flammability of toluene, along with its associated risks to human health, render early detection and real-time monitoring essential. This study explores the novel Cr2O3-core@SnO2-shell heterostructures functionalized with silver (Ag) nanoparticles to improve charge transfer and promote catalytic surface reactions. Structural analyses confirmed the formation of heterostructures, a multi-core-shell structure, and successful noble-metal decoration. The Brunauer, Emmett, and Teller (BET) analysis reported an enhanced surface area of 143.11 m2/g for 0.5%Ag-Cr2O3@SnO2. Gas sensing measurements demonstrated enhanced toluene detection at an optimal operating temperature of 200 °C. The sensor displayed outstanding repeatability and humidity-resistant behaviour over 10-50% RH, with a sub-ppm limit of detection. The enhanced performance is attributed to increased active gas adsorption sites enabled by its large surface area and adsorption volume, and to synergistic catalytic and electronic sensitization effects, promoting efficient gas adsorption and charge transfer to Ag nanoparticles.

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Authors

Prof. David E Motaung (University of the Free State, Physics Department) Kholofelo Mohloishane Seloane (University of the Free State, Physics Department)

Co-authors

Dr Rethabile Makole (Department of Mathematical and Physical Science, Central University of Technology) Dr Shaun Cronje (University of the Free State, Physics Department) Mr Katlego L Morulane (University of the Free State, Physics Department) Prof. Hendrik C Swart (University of the Free State, Physics Department)

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