Enhanced detection of ppb-level NO2 by uniform Pt-doped ZnSnO3 nanocubes

ZnSnO3 nanocubes (ZSNCs) with various Pt concentrations (i.e., 1at%, 2at%, and 5at%) were synthesized by a simple one-pot hydrothermal method. The microstructures of pure and Pt-doped ZSNCs were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Results showed that the pure ZSNCs have a perovskite structure with a side length of approximately 600 nm; this length was reduced to 400 nm after Pt doping. Following doping, PtOx (PtO and PtO2) nanoparticles with a diameter of approximately 5 nm were uniformly coated on the surface of the ZSNCs. Systematic investigation of the gas-sensing abilities of the nanocubes showed that the Pt-doped ZSNCs have excellent sensing properties toward nitrogen dioxide (NO2) gas in the operating temperature range of 75-175 degrees C. Among the sensors prepared, that based on 1at% Pt-doped ZSNCs exhibited the best response of 16.0 toward 500 ppb NO2 at 125 degrees C; this response is over 11 times higher compared with that of pure ZSNCs. The enhanced NO2 sensing mechanism of the Pt-doped ZSNCs may be attributed to the synergistic effects of catalytic activity and chemical sensitization by Pt doping.

Automated summary

In this study, ZnSnO3 nanocubes with different Pt concentrations were synthesized by a one-pot hydrothermal method. The Pt-doped nanocubes showed reduced size and the surface was coated with PtOx nanoparticles. Moreover, they exhibited excellent sensing properties towards NO2 gas, with a response over 11 times higher compared to the pure nanocubes.