Improving Hazardous Gas Detection Behavior with Palladium Decorated SnO₂ Nanobelts Networks

Transparent Conductive Oxides (TCOs) have been widely used as sensors for various hazardous gases. Among the most studied TCOs is SnO₂, due to tin being an abundant material in nature, and therefore being accessible for moldable-like nanobelts [1]. Sensors based on SnO₂ nanobelts are generally quantified according to the interaction of the atmosphere with its surface, changing its conductance [2]. The present
study reports on the fabrication of a nanobelt-based SnO₂ gas sensor, in which electrical contacts to nanobelts are self-assembled, and thus the sensors do not need any expensive and complicated fabrication processes. The nanobelts were grown using the vapor–solid–liquid (VLS) growth mechanism with gold as the catalytic site [3]. The electrical contacts were defined using testing probes; thus, the device is considered
ready after the growth process. The sensorial characteristics of the devices were tested for the detection of CO and CO₂ gases at temperatures from 25 to 75 °C, with and without palladium nanoparticle deposition in a wide concentration range of 40–1360 ppm. The results showed an improvement in the relative response, response time, and recovery, both with increasing temperature and with surface decoration using Pd
nanoparticles. These features make this class of sensors important candidates for CO and CO₂ detection for human health.

Acknowledgments: This research was funded by FAPESP, grant number 2019/18963-6, CNPq 305656/2018-0 and 304090/2022-0. The authors are grateful for institutional support from the Department of Bi-osystems Engineering at São Paulo State University (UNESP), the Department of Physics at the Federal University of São Carlos (UFSCar), and the postgraduate program in Electrical Engineering (PPGEE/UNEPS).

Reference:
[1] E.P. de Araújo, C.A. Amorim, A.N. Arantes, A.J., Appl. Phys. A. 128, 1–8, 2022.
[2] T. Zhai, X. Fang, M. Liao, X. Xu, H. Zeng, B. Yoshio, D. Golberg, 6504–6529, 2009.
[3] C.A. Amorim, K.C. Blanco, I.M. Costa, E.