Multiple-Yolk-Shell NiO Microspheres for Selective Detection of m-Xylene

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Meta-xylene (m-xylene) is a toxic volatile organic compound (VOC) with widespread industrial use.
• Accurate detection of m-xylene is crucial due to its significant risks to human health and the environment.
• Development of highly sensitive and selective gas sensors for m-xylene is a critical need.

Purpose of the Study:

• To synthesize novel NiO-based yolk-shell structures for enhanced m-xylene gas sensing.
• To investigate and compare the sensing performance of NiO-yolk double-shell (NiO-YDS) and NiO-yolk triple-shell (NiO-YTS) composites.
• To evaluate the sensitivity, selectivity, stability, and response time of the developed sensors for m-xylene detection.

Main Methods:

• Microwave-assisted solvothermal synthesis of NiO spheres.
• Preparation of NiO/Ni-BTC and NiO/Ni-PTA composites using trimesic acid (H3BTC) and p-terephthalic acid (PTA) linkers, respectively.
• Fabrication and testing of NiO-YDS and NiO-YTS gas sensors for various VOCs, including m-xylene, under dry conditions.

Main Results:

• Both NiO-YDS and NiO-YTS composites showed excellent sensitivity and selectivity for m-xylene detection.
• The NiO-YTS sensor exhibited superior sensitivity (217.5%) compared to the NiO-YDS sensor (179.8%) at 350 °C in dry air.
• The NiO-YTS sensor demonstrated stable and reproducible performance, with a low theoretical detection limit of 5.43 ppb and fast response/recovery times (89s/191s).

Conclusions:

• The synthesized NiO-YDS and NiO-YTS composites represent a promising new class of materials for highly sensitive and selective m-xylene gas sensors.
• The NiO-YTS composite, in particular, offers enhanced performance for critical m-xylene detection applications.
• The developed microwave-assisted solvothermal method provides an efficient route for fabricating advanced NiO-based gas sensing materials.