Gas sensing of ordered and disordered structure SiO2 and their adsorption behavior based on Quartz Crystal Microbalance.

• Investigation of the effect of ordered and disordered structure of silica on the gas sensing properties. • Investigation of the adsorption behavior of VOCs and small-molecule gas on the surface of silica with different structure. • Proposed different models to explain the gas adsorption behavior on the surface of silica with different structure. Ordered and disordered structure SiO 2 were fabricated on quartz crystal microbalance (QCM) chips by two different self-assembly methods. Due to the special hexagonal alignment, ordered structure SiO 2 exhibits good gas adsorption property to volatile organic compounds (VOCs) and small-molecule gases. Replacing model and Filling model were employed to explain the sensing mechanism of ordered structure SiO 2. Ordered structure SiO 2 can selectively detect VOCs due to the strong force provided by capillary condensation. While disordered structure SiO 2 exhibits higher adsorption capacity because of the abundant active sites exposed. Adsorption behavior and sensing mechanism of SiO 2 with different structure were discussed. [ABSTRACT FROM AUTHOR]