BiFeO3 nanocrystals were applied as the sensing material to isopropanol. The isopropanol sensor based on BiFeO3 nanocrystals shows excellent gas-sensing properties at the optimum working temperature of 240 °C. The sensitivity of as-prepared sensor to 100 ppm isopropanol is 31 and its response and recovery time is as fast as 6 and 17 s. The logarithmic curves of the sensitivity and concentration of BiFeO3 sensors are a very good linear in the low detection range of 2–100 ppm. In addition, the gas sensing mechanism is also discussed. The results suggest that the BiFeO3 nanomaterial can be potentially applied in isopropanol gas detection.

In this study, Strontium (Sr)-doped perovskite lanthanum manganite (La1−xSrxMnO3) nanoparticles were prepared by the sol–gel method and used as electrode materials of supercapacitors. Microstructures, morphologies, and electrochemical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), a transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) surface area measurements, cyclic voltammetry (CV), and galvanostatic charge/discharge (GCD) cycling. Investigations demonstrated that the La0.85Sr0.15MnO3 nanoparticles had a maximum specific capacitance of 185.5 F/g at a current density of 0.5 A/g and a low charge transfer resistance (0.38 Ω) in 3 M KOH aqueous electrolyte solutions. La0.85Sr0.15MnO3 electrode yields the highest capacitance behavior because of the larger specific surface area, lower charge transfer resistance, and higher concentration of oxygen vacancy. This result demonstrates that Sr doping significantly improved the electrochemical properties of the LaMnO3 system. The anion-intercalation mechanism was examined by a charge–discharge process. This provides a promising electrode material for supercapacitors.

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With the advantages of short charging and discharging times, high power density, and long cycle life, supercapacitors are regarded as one of the most promising energy storage devices and have garnered massive attention in the field of energy storage. This paper prepared La1−xCaxMnO3 (x=0, 0.05, 0.1, 0.15, and 0.2) nanoparticles by the sol‐gel method. The microstructure, morphology, and electrochemical performance of the samples were characterized. The results depict that La0.85Ca0.15MnO3 has a low charge transfer resistance (0.19 Ω) and a large specific surface area (38.79 m2 g−1). The maximum specific capacitance of the La0.85Ca0.15MnO3 sample reached 248 F/g at a current density of 0.5 A/g, which is ascribable to its large specific surface area and high oxygen vacancy concentration. The anion‐intercalation mechanism was investigated by the charging and discharging process. The above results depict that Ca‐doping significantly enhances the electrochemical performance of LaMnO3 system.

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