Preparation And Properties Of Rare Earth-C Co-doped TiO₂ Nanoparticles Loaded On Activated Carbon Fibers

In order to overcome the shortcomings of TiO₂'s wide band gap and narrow photo response range,Nd(Ce) and C were co-doped on TiO₂ in sol-gel process.Photocatalytic ability of as-prepared TiO₂ was investigated by degradation of low concentration methylene blue(MB) solution.Then,photocatalysts were loaded on activated carbon fibers(ACF) by coupling and sol-gel methods,respectively,and the cyclic decoloration abilities of two kinds of TiO₂- loaded ACF materials were compared.The results showed that the crystalline phase of Nd/C co-doped TiO₂ was anatase and the size of the photocatalysts decreased after proper doping of Nd and C.UV-vis showed that there appeared two obvious absorption peaks in the visible region.X-ray photoelectron spectroscopy(XPS) showed that C-Ti bond was formed upon the replacement of O by C, and that of Ti by Nd changed TiO₂'s lattice structure.The results of photocatalysis experiments showed that,the catalyst prepared with the sol temperature,calcining temperature and the molar ratio of Nd:C:Ti at 40℃,550℃(5℃·min^-1) and 0.006:0.15: 1,respectively,displayed the highest catalytic activity,i.e.;the decoloration degree of MB reached 24.8%after 2 h when the amount of catalyst,pH value are 2 g·L^-1 and 3 under visible light.The crystalline phase of Ce/C co-doped TiO₂ was also anatase.The red shift and inhibition effect on the particle growth via Ce/C co-doping were more obvious than those of Nd/C co-doped samples.XPS showed that replacement of Ti by Ce changed the lattice structure and Ce existed in the form of Ce⁴⁺ and Ce³⁺.The optimum conditions for preparing TiO₂-Ce-C were as follows:Ce:C:Ti=0.002:0.30:1,calcining temperature=650℃,heating rate=8℃·min^-1 and the decoloration degree of MB=63.2%after 2 h under visible light.TiO₂-Ce-C samples were loaded on ACF using coupling and sol-gel methods and the best loading rates were 5.82%and 8.41%,respectively.The catalytic activity of asprepared sample by sol-gel method is higher than that by coupling method via comparing the result of cycle decoloration experiments.SEM indicated that TiO₂-Ce-C samples prepared by sol-gel method distributed more uniformly on ACF than that prepared by coupling method.