Fe-doped TiO2 supported gold nanoparticles as high-performance CO oxidation catalysts were prepared. XRD data revealed that TiO2 support was in an anatase phase. After calcination at 300℃, the sample showed nano-tube structure, and the size of gold nanoparticles was 3.1 nm. When calcined at 500℃, most nanotubes broke, and gold nanoparticles grew up to 5.9 nm. XPS spectrum indicated the presence of Fe in the ＋3 oxidation state. Au/Fe-TiO2（Au： 1.44%, Fe： 1.35%） calcined at 300℃ possessed the best catalytic activity, and it could completely convert CO at 25℃. The temperature of 100% CO conversion（T100%） of Fe-free catalyst was 40℃. After the catalysts were stored at room temperature for 7 d, T100% of Au/Fe-TiO2 increased from 25℃ to 30℃, while T100% of Fe-free catalyst increased from 40℃ to 80℃. The catalytic activity and storage stability of Au/TiO2 could be improved by Fe-doping. The increase of specific surface area, generation of oxygen vacancies and new adsorption sites, depression of the growth of gold nanopartieles, and strong metal-support interaction were responsible for the pro-moting effect of iron on the catalytic performance of Au/TiO2 for CO oxidation.
TiO2 nanotubes supported amorphous Co-B（Co-B/TNTs） catalyst was prepared via impregnation- chemical reduction procedure. The catalyst was characterized with transmission electron microscopy（TEM）, ammonia temperature-programmed desorption（NH3-TPD）, thermogravimetry-differential thermal analysis（TG-DTA）, Fourier transform infrared spectroscopy（FTIR） and Raman spectroscopy. The effects of temperature and ratio of CO to HE on the hydroformylation of 1-octene were studied. At an optimized reaction temperature（150 ℃） and volume ratio of CO to H2（2：1）, the conversion of 1-octene can reach 97.4% with a selectivity of 23.1% for total aldehydes and n/i-aldehyde molar ratio of 40：60. To obtain higher selectivity for linear aldehydes, Co-B/TNTs modified with triphenylphosphine for the hydroformylation of 1-octene were investigated. When molar ratio of P/Co was 4, the yield of total aldehydes was the highest（31.6%） with a good selectivity for linear product（n/i-aldehyde molar ratio was 70：30）. In recycle use, the Co-B/TNTs catalyst modified with triphenylphosphine could be reused five times without reducing the activity and selectivity obviously. For a comparative study, all the Co-B/TNTs to catalyze the hydroformylation of other olefins exhibited high conversion under the optimized conditions.
SHI Yukun HU Xiaojing ZHU Baolin ZHANG Shoumin HUANG Weiping
