Sm-doped SnO2 nanoparticles synthesized via solvothermal method as a high-performance formaldehyde sensing material for gas sensors

Formaldehyde (HCHO) is a colorless and irritating volatile organic compound, which has been proven to be one of the raw materials that cause pathological building syndrome, as well as a major source of indoor environmental pollution. Long-term exposure of human body to formaldehyde will cause certain health risks, so it is of great practical significance to develop a fast and effective formaldehyde detection sensor. Tin dioxide (SnO2), an n-type semiconductor metal oxide with a specific bandgap (3.62 eV, at 300 K), has been widely used as efficient sensors material for hazardous gases detecting. Different ratios of Sm-doped SnO2 nanoparticles had been successfully prepared by a simple solvothermal route and used as sensing materials in this work. The sample structure, micromorphology, and ingredient were characterized by XRD, SEM, TEM, XPS, and other methods of formaldehyde gas-sensing characteristics were studied. The results shown the optimum compound ratio of Sm-doped SnO2 nanoparticles was 5.0 mol%, the optimal operating temperature was 160 °C, and the sensor shown high gas response, reliable stability and selectivity to formaldehyde. The sensor shown the outstanding gas-sensing performances to formaldehyde ascribed the average grain size of the Sm-doped SnO2 nanoparticles and the positive role of Sm. Besides, the possible gas-sensing mechanism of the prepared sensor to formaldehyde was analyzed in detail.