Persistently boosted TEA sensing performance of In2O3 hollow spheres by sequentially modified with Bi2O3 and Pt nanoparticles

Exploring rational and feasible strategies to boost the gas sensing performance of metal oxide semiconductor (MOS) has attracted a growing concern because it is an inevitable path for advanced gas sensor. Herein, a Bi2O3 and Pt co-modification approach was proposed to upgrade the triethylamine (TEA) sensing performance of In2O3. To expound it, a series of hollow spheres (HSs) with different compositions including In2O3, Bi2O3-modified In2O3 (Bi2O3/In2O3), and Bi2O3 and Pt co-modified In2O3 (Pt/Bi2O3/In2O3) were prepared through a solvothermal-calcination route combined with subsequent chemical reduction. After the evolution from In2O3 to binary Bi2O3/In2O3 and ternary Pt/Bi2O3/In2O3 composites, the sensor exhibited a persistently boosted sensing performance to TEA, particularly of higher sensitivity (increased from 0.0219 to 0.0369 and 1.0319/ppm within 1-30 ppm), better selectivity (STEA/Methane increased from 17.6 to 23.7 and 257.2), and faster response speed (response time decreased from 7 to 3 and 1 s for 100 ppm TEA). Additionally, the best Pt/Bi2O3/In2O3 sensor also presented good repeatability and stability. The sensitization effects of Pt and Bi2O3-In2O3 p-n heterojunction were discussed in detail.