Synthesis of three-dimensionally ordered macroporous LaFeO3 with enhanced methanol gas sensing properties

Three-dimensionally ordered macroporous (3DOM) LaFeO3 was synthesized by a simple PMMA template method. The structure morphology and composition of as-prepared products have been characterized by SEM, XRD, and TEM. The products show long-range ordered hexagonal arrangement forming an inverse opal nanostructure. The surface area of 3DOM LaFeO3 is almost twice larger than that of bulk LaFeO3. The methanol gas sensing performance of 3DOM LaFeO3 was systemically studied. The as-performed samples show p-type semi-conducting properties for all the tested gases within the temperature range of 150-300 °C. The 3DOM LaFeO3 shows the highest gas response (as high as 96) and the fastest response-recovery times at 190 °C. In addition, it shows superior selectivity to methanol. This enhancement in gas-sensing properties is attributed to its ordered macro-mesoporous structure, large surface area, numerous surface active sites and oxygen vacancies.