Ti-HMS介孔分子筛的制备及其在一氧化氮催化分解反应中的活性(英文)

Preparation of Ti-HMS Mesoporous Molecular Sieves and Their Photocatalytic Activity for Decomposition of Nitrogen Oxide

在常温下制备了具有不同钛含量的大比表面积和孔体积的介孔分子筛HMS .XRD谱表明 ,这些Ti HMS样品呈现出很好的六方晶形 .经焙烧后 ,Ti HMS样品的UV吸收光谱和XAFS谱结果表明 ,在Ti HMS( 1 )和Ti HMS( 2 )骨架中的钛离子以四配位存在 ,而在Ti HMS( 1 0 )中至少有部分钛是以六配位存在 .在NO存在的情况下 ,在 2 73K下光催化剂Ti HMS受紫外光照射后 ,导致NO分解生成N2 ,O2 和N2 O .实验结果表明 ,具有高分散四配位钛的Ti HMS( 1 )使NO以高效率、高选择性分解生成N2 和O2 ;随着钛含量的增加 ,其光催化活性反而降低 .

Various Ti containing HMS mesoporous molecular sieves, having large surface area and pore volume, have been prepared at ambient temperature. The Ti HMS samples exhibited a well defined XRD pattern typical of hexagonal lattice. UV Vis and XAFS spectra of the calcined Ti HMS samples indicated that the Ti ions are tetrahedrally coordinated in the framework of HMS for Ti HMS(1) and Ti HMS(2), while for Ti HMS(10), at least a fraction of Ti ions is in octahedral coordination. UV irradiation on the Ti HMS samples in the presence of NO at 273 K led to decomposition of NO to N 2, O 2, and N 2O with different yields and distributions. The photocatalytic performance of the TiO 2 appears to be completely modified by the incorporation structure and the reaction environment. High efficiency and selectivity for formation of N 2 and O 2 in the photocatalytic decomposition of NO were achieved over Ti HMS(1) having highly dispersed tetrahedral titanium species, but the activity decreased with the increase of Ti content in the sample.