Preparation of biomorphic porous LaFeO3 by sorghum straw biotemplate method and its acetone sensing properties

Biomorphic porous LaFeO3 has been successfully fabricated using sorghum straw as biotemplate. This simple synthesis route could be expected to be extended for the preparation of biomorphic porous metal oxide gas-sensing materials. The structure and morphology of the products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and N2 adsorption–desorption analyses. Testing results reveal that the as-prepared LaFeO3 shows the porous and network frameworks, which replicas with the structure characterizations of sorghum straw. Moreover, the framework is assembled by a large amount of interconnected nanocrystallites with the sizes of about 20–30 nm, and there are plenty of voids between the nanocrystallites in the framework. Gas sensing investigation showed that the sensor based on biomorphic porous LaFeO3 exhibited higher response to acetone gas compared with that of bulk LaFeO3 particles. The enhancement in gas sensing properties was attributed to their porous structure, large surface areas, numerous surface active sites and more oxygen vacancies.