Designed synthesis of yolk-shell WO3 microspheres for enhanced phenylamine sensing performance at room temperature

Abstract Yolk-shell structures have drawn enormous research interest regarding their improved gas sensing performance. In this work, solid, hollow and yolk-shell WO3 microspheres have been prepared by sonchemical precipitation and hydrogen-lead ions exchange methods with a subsequent calcination process. Hollow and yolk-shell structures can be selectively obtained through simply adjusting the steps of leaching process. The as-obtained samples are systematically investigated by X-ray powder diffraction, field emission scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and N2 adsorption-desorption apparatus. The yolk-shell WO3 microspheres served as a gas sensing material exhibit enhanced phenylamine sensing performance at room temperature compared with solid and hollow structures. Besides, superior selectivity, great anti-humidity properties and excellent long-term stability are also observed. The enhanced gas sensing mechanism is also discussed.