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The development of cost-effective simple methods to fabricate nanocomposites based on metal oxide (MOX) supported noble metals with improved performance is extremely demanding, specifically in the field of nanomaterial and gas sensor. In this this work, a facile one-step hydrothermal strategy to synthesize strongly-coupled TiO2 nanosheets supported with Ag nanoparticles (Ag/TiO2 heterojunction nanocomposites) is proposed, which is proved of high effectiveness for sensor applications. The structure and morphology of synthesized nanocomposites was performed by XRD, XPS, HRTEM, UV-Vis and PL spectroscopy. Compared to pristine TiO2, the sensors based on such Ag/TiO2 heterojunction nanocomposites show excellent ethanol gas sensing properties in terms of high sensitivity (8.5 towards 100 ppm), selectivity against other gases (methanal, acetone, and methanol), short response/recover times (9/10 s), and high stability (present stable response after 30 days). Such performance demonstrates this material is promising for practical gas sensor applications. [ABSTRACT FROM AUTHOR]

The paper demonstrated cost-effective one-step hydrothermal process to synthesize TiO2 microrods modified with Cr2O3 nanoparticles. The crystal structure, microstructure and chemical composition of the obtained materials were characterized by XRD, SEM, TEM and EDS analysis. Subsequently, for gas sensor tests the sensors were fabricated onto a ceramic tube having a designed pair of Au electrodes with four Pt wires. The results indicate that the sensors based on the optimal content of Cr2O3 nanoparticles modified TiO2 microrods possess excellent gas-sensing performance to acetone. Specifically, the sensor based on optimal 3% Cr2O3 modified TiO2 microrods exhibited high response (15), fast response/recovery time (5/28 s), outstanding selectivity (against 100 ppm ethanol, methanol and formaldehyde) and good stability (1-40 days) towards 100 ppm acetone at 300 °C. Relying on the analysis, we infer that performance can be controlled by varying the Cr2O3 contents. A plausible sensing mechanism is also discussed to explain the reasons for the enhanced acetone sensing with Cr2O3-TiO2 heterostructures. [ABSTRACT FROM AUTHOR]