Chemiresistive detection of xylene vapor using MOF-derived porous Co3O4 microrods activated by Mo6+ cations

• Published in: Sensors and actuators. B, Chemical Chemical, 2025-01, Vol.422, p.136658, Article 136658
• Main Authors: Yang, Wei, Fang, Baijun, Zhang, Yuanhui, Ma, Guoming, Meng, Hu, Liu, Shantang
• Format: Article
• Language: English
• Subjects: Co3O4 microrods; Gas sensor; Metal-organic framework; Reaction pathway; Xylene
• ISSN: 0925-4005
• DOI: 10.1016/j.snb.2024.136658

Incorporation of high-valence cation into catalytic oxide (eg. Co3O4) is favorable for regulating the carrier concentration and creating more active centers for surface reaction process, thus promoting the sensing capability towards low reactive gas (eg. xylene). Herein, the metal-organic framework (MOF)-derived Mo-doped porous Co3O4 microrods are achieved through a simple solution method combing with a thermal method. The introduction of Mo6+ into Co3O4 matrix enhances the concentration of oxygen defects and Co3+, coupled with the specific surface area. As a result, the 5 at% Mo/Co3O4-based gas sensor sample exhibits a nice selectivity, clear response value (Rg/Ra=29.8 – 100 ppm), low concentration limit (0.5 ppm), and reliable stability to xylene vapor under a low working temperature (140 °C). Moreover, the possible reaction pathway (benzyl-benzaldehyde-benzoate-aromatic ester/anhydride) of xylene oxidation over this 5 at% Mo-doped Co3O4 microrod is proved by an in-situ DRIFTS analysis. Importantly, this optimized xylene-sensing capability is further discussed from the viewpoint of Mo-introducing effect into the porous Co3O4 microrods. This work further demonstrates a reliable approach of high valence cation-doped catalytic oxides to detect low reactive vapor. [Display omitted] •MOF-derived Mo-doped porous Co3O4 microrods are successfully demonstrated.•Xylene-sensing capability of this Co3O4 is clearly enhanced via 5 at% Mo-doping.•In-situ DRIFTS reveals the possible intermediates in the xylene-sensing events.•Structural merits and synergistic catalytic activity contribute the enhanced ability.