Magnetic behavior, photocatalytic activity and gas-sensing performance of porous lanthanum ferrites powders

Porous perovskite lanthanum ferrites (LaFeO3) powders were synthesized under the different pH value by sol-gel technique and self-propagating combustion method. After the characterization with XRD, SEM, VSM, nitrogen adsorption-desorption isotherm and UV-Vis spectroscopy, the magnetic properties, photocatalytic activity and gas-sensing performance are discussed in detail. All LaFeO3 samples exhibit ferromagnetism for the spin mismatch due to oxygen vacancies. LaFeO3 powders present the good photocatalytic performance to MB and could be easily separated by magnetic separation technique after photocatalysis. Furthermore, the LaFeO3 gas sensors exhibited the considerable sensitivity to ethanol gas. Among all samples, LF-1 (LaFeO3 powders prepared at pH = 1) present the highest removal rate of MB (68%), the largest saturation magnetization (4.57 emu/g) and the best gas response to ethanol. The highest response for LF-1 sensor reaches (263.4) at the optimized operating temperature of 250 C to 100 ppm ethanol gas, which should be attributed to the higher oxygen vacancies.

Automated summary

Porous perovskite lanthanum ferrites powders were synthesized under different pH values and showed good performance in magnetic properties, photocatalytic activity, and gas-sensing performance. The LF-1 sample prepared at pH = 1 exhibited the highest removal rate of MB, the largest saturation magnetization, and the best gas response to ethanol.