Electrospun Ag-TiO Nanofibers for Photocatalytic Glucose Conversion to High-Value Chemicals.

TiO nanofibers were fabricated by combination of sol-gel and electrospinning techniques. Ag-doped TiO nanofibers with different Ag contents were prepared by two different methods ( electrospinning or wetness impregnation of Ag on TiO nanofibers) and heat treated at 500 °C for 2 h under an air or N atmosphere. The obtained catalysts were characterized by field emission scanning electron microscopy, X-ray diffraction, photoluminescence, and N adsorption analyzed by the Brunauer-Emmett-Teller (BET) method. Photocatalytic glucose conversions with electrospun TiO and Ag-doped TiO nanofibers for production of high-value products were carried out. From different doping methods, the results indicated that 1 wt % Ag-TiO nanofibers prepared by an method with calcination under N achieved the highest glucose conversion (85.49%). From several Ag loading contents (i.e., 0, 1, 2, and 4 wt %) in Ag-doped TiO nanofibers, the nanofibers exhibited different glucose conversions [in order of 2 wt % (99.65%) > 1 wt % (85.49%) > 4 wt % (77.72%) > 0 wt % (29.64%)]. Arabinose, xylitol, gluconic acid, and formic acid were found as the high-value chemicals with the photocatalytic reaction of TiO and Ag-doped TiO nanofibers under UVA irradiation. Product yields of each converted chemicals from different photocatalysts from different Ag loading contents showed relatively same trends with the glucose conversion. From all results, it can be concluded that the good characteristics of 2 wt % Ag-TiO nanofibers such as the smallest anatase crystallite size (8.25 nm) and the highest specific surface area ( = 53.69 m/g) promoted the highest photocatalytic activity. Additionally, TiO and Ag-doped TiO nanofibers exhibited higher photocatalytic performance for glucose conversion than commercial TiO (P25) and synthesized TiO nanoparticles. Finally, Ag-doped TiO nanofibers showed recycling ability with high photocatalytic glucose conversion after four-time use.