A novel ethanol gas sensor based on α-BiMoO/CoO nanotube-decorated particles.

A novel composite based on α-BiMoO/CoO nanotube-decorated particles was successfully synthesized using a highly efficient and facile two step system using electrospinning and hydrothermal techniques. The small size CoO nanoparticles were uniformly and hydrothermally developed on the electrospun α-BiMoO nanotubes. The pure α-BiMoO nanofibers and composite based on α-BiMoO/CoO were examined using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analyses. From the BET measurements, the composite based on α-BiMoO/CoO exhibits a large specific surface area of 54 m g with mesopore diameter ranges of 2-10 nm, which is mainly attributed to the remarkable and dominant enhancement in gas sensing as compared to that of the pure α-BiMoO nanofibers (38 m g) and CoO nanoparticles (32 m g), respectively. In this work, the novel composite based on α-BiMoO/CoO presented a high sensitivity of 30.25 with a quick response/recovery speed towards 100 ppm ethanol at an optimal working temperature of 170 °C, as compared to the pure α-BiMoO nanofibers and CoO nanoparticles, which display a sensitivity of 13.10 and 2.99 at an optimal working temperature of 220 °C and 280 °C. The sensing performance of the composite based on the α-BiMoO/CoO sensor exhibits a superior sensing performance towards ethanol, which might be owed to the enormous number of superficial oxygen species, the small size catalytic effect of the CoO nanoparticles and the interfacial effect formed between the n-type α-BiMoO and p-type CoO leading to a high charge carrier concentration. This is a novel investigation of a composite based on an α-BiMoO/CoO sensor in the gas sensing era, which might be of vital importance in applications in the advanced gas sensing field.