High selectivity methanol sensor based on Co-Fe2O3/SmFeO3 p-n heterojunction composites

A high-performance methanol gas sensor based on Co-Fe2O3/SmFeO3 p-n heterojunction composite was prepared by sol-gel method with molecular imprinting technology (MIT). The composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), respectively. The results indicate that the Co2+/Co3+ entered Fe2O3 by replacing Fe3+ which formed Co-Fe2O3, and constituted p-n heterojunction with SmFeO3. The methanol gas sensing properties of Co-Fe2O3/SmFeO3 were investigated. The formation of Co-Fe2O3/SmFeO3 with MIT exhibited ultrahigh response, quick sensitivity and significant selectivity. The sensor based on Co-Fe2O3/SmFeO3 with MIT to 5 ppm methanol gas at 155 degrees C was 19.7 while the response to other test gases lower than 9. The superior sensing performance of composites attributes to the different Fermi levels of CoFe2O3 and SmFeO3 so that the electron delivered across the Co-Fe2O3/SmFeO3 interfaces through band. The results reveal that Co-Fe2O3/SmFeO3 would be a promising methanol gas sensing materials. (C) 2018 Elsevier B.V. All rights reserved.