Rice-grain Sm2O3/SmFeO3 nanoparticles as high selectivity formaldehyde gas sensor prepared by precipitation

[Display omitted] •One-step synthesis of rice grains Sm2O3/SmFeO3 nanoparticles by precipitation.•Excellent selectivity for HCHO.•The gas sensing performance of Sm2O3/SmFeO3 to formaldehyde was investigated for the first time.•The rice grains Sm2O3/SmFeO3 nanoparticles sensor is well suited for detecting low concentration formaldehyde. In this study, rice-grain Sm2O3/SmFeO3 nanoparticles were fabricated by a convenient precipitation method. In addition, the structure and morphology of the Sm2O3/SmFeO3 nanoparticles were characterized by XRD, BET, SEM, and TEM. The XRD patterns reveal that diffraction peaks of Sm2O3/SmFeO3 nanoparticles are in excellent agreement with those of SmFeO3 and Sm2O3. By using the Debye–Scherrer equation, the average grain size of the rice-grain particles of the sample was calculated to be 23.4 nm. BET showed that the material has a larger specific surface area. SEM and TEM results indicate that the material comprises millet rice-grains. The resulting Sm2O3/SmFeO3-based sensor exhibited good sensitivity performance, with excellent selectivity for formaldehyde gas. At the optimum work temperature (190 °C), the response value, response time, and recovery time for 10 ppm formaldehyde were 44, 111 s, and 102 s, respectively. These results reveal that rice-grain Sm2O3/SmFeO3 material demonstrates promise as a formaldehyde-gas-sensitive material.