Anatase TiO_(2)nanospindles containing 89%exposed{101}facets(TIO_(2)-101)and nanosheets with 77%exposed{001}facets(TiO_(2)-001)were hydrothermally synthesized and used as supports for Pd catalysts.The effects of the T...Anatase TiO_(2)nanospindles containing 89%exposed{101}facets(TIO_(2)-101)and nanosheets with 77%exposed{001}facets(TiO_(2)-001)were hydrothermally synthesized and used as supports for Pd catalysts.The effects of the TiO_(2)materials on the catalytic performance of Pd/TiO_(2)-101 and Pd/TiO_(2)-001 catalysts were investigated in the selective hydrogenation of acetylene to polymer-grade ethylene.The PdfTiO_(2)-101 catalyst exhibited enhanced performance in terms of acetylene conversion and ethylene yield.To understand these effects,the catalysts were characterized by H_(2)temperature-programmed desorption(H_(2)-TPD),H_(2)temperature-programmed reduction(H=-TPR),transmission electron microscopy(TEM),pulse CO chemisorption,X-ray photoelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).The TEM and CO chemisorption results confirmed that Pd nanoparticles(NPs)on the TiO_(2)-101 support had a smaller average particle size(1.53 nm)and a higher dispersion(15.95%)than those on the TiO_(2)-001 support(average particle size of 4.36 nm and dispersion of 9.06%).The smaller particle size and higher dispersion of Pd on the Pd/TiO_(2)-101 catalyst provided more reaction active sites,which contributed to the improved catalytic activity of this supported catalyst.展开更多
We have made,for the first time,a trial study of the electric behaviours of the 450℃ annealed CZ-Si having several different dopings.Four energy levels were observed(E_(1)=E_(c)-(280-350)meV;E_(2)=E_(c)-(110-120)meV;...We have made,for the first time,a trial study of the electric behaviours of the 450℃ annealed CZ-Si having several different dopings.Four energy levels were observed(E_(1)=E_(c)-(280-350)meV;E_(2)=E_(c)-(110-120)meV;E_(3)=E_(c)-(52-60)meV;E_(4)=E_(c)-30meV)in p-Si samples,which were capable of undergoing type change after annealing.In the heat-treated n-Si samples,only E_(2) and E_(4) were observed.Although these levels correspond to different structure models,they are all related,in one way or another,to the oxygen atoms in Si.展开更多
文摘Anatase TiO_(2)nanospindles containing 89%exposed{101}facets(TIO_(2)-101)and nanosheets with 77%exposed{001}facets(TiO_(2)-001)were hydrothermally synthesized and used as supports for Pd catalysts.The effects of the TiO_(2)materials on the catalytic performance of Pd/TiO_(2)-101 and Pd/TiO_(2)-001 catalysts were investigated in the selective hydrogenation of acetylene to polymer-grade ethylene.The PdfTiO_(2)-101 catalyst exhibited enhanced performance in terms of acetylene conversion and ethylene yield.To understand these effects,the catalysts were characterized by H_(2)temperature-programmed desorption(H_(2)-TPD),H_(2)temperature-programmed reduction(H=-TPR),transmission electron microscopy(TEM),pulse CO chemisorption,X-ray photoelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).The TEM and CO chemisorption results confirmed that Pd nanoparticles(NPs)on the TiO_(2)-101 support had a smaller average particle size(1.53 nm)and a higher dispersion(15.95%)than those on the TiO_(2)-001 support(average particle size of 4.36 nm and dispersion of 9.06%).The smaller particle size and higher dispersion of Pd on the Pd/TiO_(2)-101 catalyst provided more reaction active sites,which contributed to the improved catalytic activity of this supported catalyst.
文摘We have made,for the first time,a trial study of the electric behaviours of the 450℃ annealed CZ-Si having several different dopings.Four energy levels were observed(E_(1)=E_(c)-(280-350)meV;E_(2)=E_(c)-(110-120)meV;E_(3)=E_(c)-(52-60)meV;E_(4)=E_(c)-30meV)in p-Si samples,which were capable of undergoing type change after annealing.In the heat-treated n-Si samples,only E_(2) and E_(4) were observed.Although these levels correspond to different structure models,they are all related,in one way or another,to the oxygen atoms in Si.
