Construction of novel Pd-SnO2 composite nanoporous structure as a high-response sensor for methane gas

The reasonable design of the semiconducting metal oxides modified by noble metal element compositing and the ingenious construct of the particular microstructure have been proved to be an effective method to promote the gas sensing capability of chemiresistor-type sensors. Herein, Pd-SnO2 composite nanoporous structure is fabricated by a controllable and low-power hydrothermal method. A novel weak acid glucose-assisted growth method is proposed to promote the formation of nanoporous structure. Under weak acidic environment, the complete hydrolysis of precursor (SnCl4 center dot 5H(2)O), leading to nanocrystallines hard to grow and create a large number of small nanoparticles with an average crystallite size of similar to 10 nm, which assemble to form interstitial holes between nanoparticles. The experimental results reveal that the Pd-SnO2 composite nanoporous structure exhibits prominent methane (CH4) gas sensing performances as compared with pure SnO2 nanoparticles. Especially, 2.5 mol% Pd-SnO2 composite nanoporous structure based on sensor shows an ultra-fast response of 17.60 at 3000 ppm within 3 s to reach a stable-state and fast recovers within 5 s at an operating temperature of 340 degrees C, it has barely been reported that the sensor based on CH4 gas presented such excellent performances. And more importantly, the sensor based on 2.5 mol% Pd-SnO2 composite nanoporous structure also possesses high repeatability and long-term stability. These results are due to the fact that the unique nanoporous structures of composite and the chemical sensitization and electronic sensitization of Pd, which provide an effective strategy to achieve eminent gas-sensing performances of CH4 gas sensors. (C) 2020 Elsevier B.V. All rights reserved.