Realizing the Control of Fermi Level and Gas-Sensing Selectivity over Gallium-Doped In2O3 Inverse Opal Microspheres

21 Jun 2019, 12:20
15m
Ferrara, Italy

Ferrara, Italy

Speaker

Mr Tianshuang Wang

Description

Herein, formaldehyde sensors based on gallium-doped In2O3 inverse opal (IO-(GaxIn1-x)2O3) microspheres were purposefully prepared by simple ultrasonic spray pyrolysis method combined with self-assembly sulfonated polystyrene spheres template. The well-aligned inverse opal structure, with three different-sized pores, plays dual roles of accelerating the diffusion of gas molecules and providing more active sites. The Ga substitutional doing can alter the electronic energy level structure of (GaxIn1-x)2O3, leading to the elevation of Fermi level and the modulation of band gap closed to a suitable value (3.90 eV), hence, effectively optimizing the oxidative catalytic activity for preferential CH2O oxidation and increasing the amount of absorbed oxygen. More importantly, the gas selectivity could be controlled by varying the energy level of adsorbed oxygen. Accordingly, the IO-(Ga0.2In0.8)2O3 microspheres sensor showed high response toward formaldehyde with fast response and recovery speeds, and ultralow detection limit (50 ppb). Our findings finally offer implications for designing Fermi level-tailorable semiconductor nanomaterials for the control of selectivity and monitoring indoor air pollutant.

Summary

Taken together, the results have demonstrated the electronic energy level structure controllability of the spray pyrolysis-doping synthesis of (GaxIn1-x)2O3 nanomaterials and its synergistic impact on the oxidative catalytic activity for preferential CH2O oxidation.

Primary author

Mr Tianshuang Wang

Co-authors

Prof. Sun Peng Prof. Geyu Lu

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