Preparation of Novel Ag-Si-TiO2 Composite and Research on Its Photocatalytic Degradation of Formaldehyde

A novel Ag-Si-TiO2 composite was prepared via sol-gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag-Si-TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N-2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e(-)-h(+)) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag-Si-TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.

Automated summary

The novel Ag-Si-TiO2 composite material showed efficient catalytic performance for removing residual formaldehyde in shiitake mushrooms. The optimal catalytic efficiency was achieved with 6.0 wt%Ag-3.0 wt%Si-TiO2 samples, reaching a degradation efficiency of 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation could be described by Langmuir-Hinshelwood first-order kinetic model.