In the present work, novel lanthanum‑iron binary oxide nanoparticles are used as adsorbents for fluoride removal from aqueous solution and oxygen gas sensor. The lanthanum‑iron binary oxide nanoparticles were synthesized using co-precipitation method and sintered at a temperature of 100 °C, 450 °C, and 900 °C for 2 h. The material, optical and electrical properties of the nanoparticles were investigated by the instrumental characterization of high-resolution scanning electron microscope and high-resolution transition electron microscope to determine the structure, vibrating sample magnetometer which confirmed the superparamagnetic behavior, BET surface area analysis to affirm the mesoporous nature, X-ray photoelectron spectroscopy to confirm the oxidation states, X-ray diffraction, Fourier transform infrared spectroscopy, and I-V analysis, respectively. The adsorption of fluoride carried out in batch system, the experimental data were analyzed using isotherm and regeneration studies. The results demonstrated that the LIBONs sintered at 100 °C showed exceptional fluoride removal with maximum adsorption of 14.49 mg g −1 at pH 6.5 ± 0.5. The regeneration percentage of 80% was obtained after fifth cycle. The nanoparticles sintered at 900 °C rendered good sensitivity and response/recovery characteristics towards 50% of oxygen at operating temperature of 350 °C.