模拟可见光下掺杂TiO_2对甲醛溶液光催化降解

模拟自然条件下的可见光,以甲醛的光催化降解为探针反应,评价了通过溶胶-凝胶法分别制备的8种（银Ag、铜Cu、铁Fe、钨W、铈Ce、镧La、硫S、氯Cl）掺杂TiO2纳米晶体的光催化活性及对甲醛水溶液的去除效果。用X射线衍射、激光粒度分析和紫外-可见分光光谱表征了掺杂纳米TiO2的微晶尺寸、晶体结构与光学性能。结果表明：Ce离子尽管有较大的半径但是主要还是掺杂到晶格中,Ce掺杂可以促进TiO2由非正分锐钛矿相向锐钛矿相和金红石相的转变,抑制载流子复合,使TiO2的光吸收带边发生红移且有利于对可见光的吸收,从而使Ce掺杂TiO2在模拟可见光下光催化甲醛水溶液的能力得到明显提高。

Photocatalytic degradation of formaldehyde by doped TiO_2 under simulated visible lamp

TiO2 nanocrystalline photocatalysts doped with Ag,Cu,Fe,W,Ce,La,S,Cl respectively were prepared by the sol-gel method.The photocatalytic activites of the samples were determined and removal effect of formaldehyde was investigated by the photocatalytic decomposition of formaldehyde using a visible lamp.The characteristics of the samples were characterized by means of X-ray diffraction,laser particle size analyzer and ultraviolet-visible spectrum spectrometer.The effect of doping on the crystallite sizes,crystal pattern and optical properties of catalysts were surveyed.The results showed that Ce ions was still doped into intentionally the crystal lattice,although big radius,repressing the transformation from anatase phase of non-stoichiometric to anatase and rutile,restraining the recombination of charge carrier,causing a red-shift of the onset of the absorption spectrum and enhancing the visible lamp absorption ability of TiO2.The effects are responsible for the remarkable increase in potocatalytic decomposition of formaldehyde on Ce-doped TiO2 under simulated visible lamp.