La³⁺ doped CaFe₂O₄ materials: Preparation and detection of ultra-low concentrations of formaldehyde at room temperature

La3+ doped CaCaFe2O4 materials have been synthesized by the electrospinning method. The structure and morphology of obtained samples were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Subsequently, the influence of the doping amount (mass fraction) of La3+ on the gas-sensing properties of CaFe2O4 was investigated. The results indicated that 3% La3+ doped CaCaFe2O4 materials exhibited the highest response value (R-a/R-g=14.1) to 100 mu L center dot L-1 formaldehyde at room temperature. More importantly, the detection limit was as low as 0.1 nL center dot L-1, and the response/ recovery time only was 4.3 s/8.4 s.