Fabrication And Catalytic Properties Of Bimetal Loaded Titanium Dioxide Nanobelts

Titanium dioxide is a common multifunctional semiconductor. It was widely used in different industries, including photocatalyst, solar cells and biosensors. It was more and more important for TiO2used as catalyst support, especially in the catalytic and photocatalytic fields. The development and application of TiO2were limited because of its existence of powder. Recently, the development of one dimensional nanomaterials provide a new way for TiO2material. Meanwhile, the research of TiO2one dimensional material used as catalyst support increased quickly. So TiO2one dimensional material has a bright future in industrial application.In this paper, we synthesized TiO2nanobelts through the hydrothermal method used titanium dioxide (P25) as a precursor. Ag/TiO2-NBs was obtained by the photodeposited method, Au-Ag/TiO2-NBs was fabricated by a galvanic replacement in HAuCl4solution. The bimetallic structure of Au-Ag/TiO2-NBs was detected by transmission electronic microscope (TEM), the metal particles were all sub-3nm, and finely dispersed on the surface of TiO2nanobelts. X-ray photoelectron spectroscopy (XPS) and UV-vis spectra were conducted to make sure the composition of this structure. The test suggested that silver existed in the form of silver oxide, and gold was metallic state.Compared with monometallic structure (Ag/TiO2-NBs or Au/TiO2-NBs), Au-Ag/TiO2-NBs has a synergistic effect, so it has a higher catalytic performance. More importantly, we synthesized a monolithic catalyst through the modified paper-making process based on the bimetallic Au-Ag/TiO2-NBs. And this catalyst exhibited good catalytic performance in the gas phase oxidation of benzyl alcohol at240℃and atmospheric pressure (The composition of carrier gas is O2/N2=1:4). Its TOF was2570h"1, and selectivity of benzaldehyde was over99%. The metal particle size of this catalyst had no obvious change after the gas phase oxidation. The size of Au-Ag nanoparticle became1.92nm from1.48nm. Furthermore, TiO2nanobelts had no sintering during the oxidation process showed by the scanning electron microscope (SEM). There are two reasons for the high stability of this catalyst, on one hand, the sintering resistance of TiO2nanobelts act as the noble metal catalyst support plays an important role. On the other hand, the metal particles had no agglomeration during the process because of the fix effect of metal particles on TiO2nanobelts. The existence of silver oxide in the metal particle also plays a role for the stability.We synthesized other noble metal bimetallic catalysts supported on TiO2-NBs through this method. And we conducted the photocatalysis experiment of organic dye degragation to evaluate the photocatalytic activity of those samples. As a result, Ag-Pd/TiO2-NBs, Ag-Pt/TiO2-NBs and Au-Cu/TiO2-NBs have certain photocatalytic activity, and they have widely use in the treatment of waste water in the future.