A novel ethanol gas sensor based on α-Bi(2)Mo(3)O(12)/Co(3)O(4) nanotube-decorated particles

A novel composite based on α-Bi(2)Mo(3)O(12)/Co(3)O(4) nanotube-decorated particles was successfully synthesized using a highly efficient and facile two step system using electrospinning and hydrothermal techniques. The small size Co(3)O(4) nanoparticles were uniformly and hydrothermally developed on the electrospun α-Bi(2)Mo(3)O(12) nanotubes. The pure α-Bi(2)Mo(3)O(12) nanofibers and composite based on α-Bi(2)Mo(3)O(12)/Co(3)O(4) 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-Bi(2)Mo(3)O(12)/Co(3)O(4) exhibits a large specific surface area of 54 m(2) g(−1) 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-Bi(2)Mo(3)O(12) nanofibers (38 m(2) g(−1)) and Co(3)O(4) nanoparticles (32 m(2) g(−1)), respectively. In this work, the novel composite based on α-Bi(2)Mo(3)O(12)/Co(3)O(4) 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-Bi(2)Mo(3)O(12) nanofibers and Co(3)O(4) 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-Bi(2)Mo(3)O(12)/Co(3)O(4) 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 Co(3)O(4) nanoparticles and the interfacial effect formed between the n-type α-Bi(2)Mo(3)O(12) and p-type Co(3)O(4) leading to a high charge carrier concentration. This is a novel investigation of a composite based on an α-Bi(2)Mo(3)O(12)/Co(3)O(4) sensor in the gas sensing era, which might be of vital importance in applications in the advanced gas sensing field.