Morphology-Controlled Synthesis of BiVO4 Materials and Their Ethanol Gas Sensing Properties

BiVO4 porous microspheres were fabricated by a facile hydrothermal reaction. Various analytical techniques such as x-ray diffraction, scanning electron microscope, x-ray photoelectron spectroscopy, and N2 adsorption-desorption were adopted to characterize their structure, morphology, and chemical composition. The results showed the molecular weight of PEG had a significant influence on the morphologies of BiVO4 samples, and high molecular weight of PEG favored the formation of porous sphere-shaped nanostructure due to longer chain-like coordination complexes. The gas sensing properties of these BiVO4 microspheres were further investigated, and all the four BiVO4 sensors demonstrated the increasing responses with the increase of working temperatures, and reached their maximum values at 340 °C. The ethanol-selective characteristics of the BiVO4 sensor synthesized by the assist of PEG1000 towards 200 ppm ethanol presented significantly higher gas response than all the other interfering gases. Moreover, the BiVO4 sensor also displayed fast response/recovery, and excellent stability for 14-day continuous measurement.