Hydrothermal synthesis of Bi-doped SnO2/rGO nanocomposites and the enhanced gas sensing performance to benzene

In this work, we report on a novel one-pot hydrothermal synthesis of bismuth (Bi)-doped SnO2/rGO nanocomposites. The composite structures, surface morphologies, chemical compositions, optical properties and crystal defects were characterized by XRD, SEM, TEM, BET, FTIR, Raman, XPS, EPR, PL and UV-vis techniques, and the gas sensing properties to benzene (C6H6) were investigated thoroughly by the temperature-controlled CGS-1TP gas sensing test system. Compared with that of the pure SnO2 and rGO/SnO2, the Bi-doped SnO2/rGO presented largely enhanced gas sensing properties to benzene. Its high gas response, fast response-recovery characteristic, good stability and selectivity made Bi-doped SnO2/rGO an ideal sensing material to detect benzene. However, the as-prepared Bi-doped SnO2/rGO based sensor also showed degenerative gas sensing performance at high humidity. The enhanced gas sensing performances of Bi-doped SnO2/rGO could be attributed to the large specific surface area of the composite structure, the unique rGO-SnO2 heterojunctions, the narrowed band gap, and enormous oxygen vacancies. This novel Bi-doped SnO2/rGO composite promises to provide an essential gas sensing material for the detection of benzene.