A series of cerium phosphate catalysts with different crystal phases were synthesized by hydrothermal method and co-precipitation method.Hexagonal cerium phosphate(CePO_(4)-H)shows better NH_(3)-SCR denitration activi...A series of cerium phosphate catalysts with different crystal phases were synthesized by hydrothermal method and co-precipitation method.Hexagonal cerium phosphate(CePO_(4)-H)shows better NH_(3)-SCR denitration activity than monoclinic cerium phosphate(CePO_(4)-M)and mixed phases of CePO_(4)-H and CePO_(4)-M.Moreover,CePO_(4)-H also exhibits excellent activity stability with stream time and cycling stability.Various characterizations were carried out to explain the effects of different crystal phases of CePO_(4)on the activity.Among these catalysts,CePO_(4)-H has much stronger surface acidity that is conducive to the adsorption and activation of NH_(3),and more surface adsorbed oxygen species that can effectively improve SCR activity.In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)were performed to investigate the adsorption and reaction of NH_(3)and NO_(x)on CePO_(4)-H and CePO_(4)-M,and the results suggest that the better activity over CePO_(4)-H follows mainly the Eley-Rideal mechanism in the activity temperature window(300-500℃)with 100%NO conversion.展开更多
CuO/SBA-16 catalysts were prepared by two different routes–the conventional impregnation method and the modified impregnation method with pH adjustment.These catalysts were characterized by X-ray diffraction(XRD),ato...CuO/SBA-16 catalysts were prepared by two different routes–the conventional impregnation method and the modified impregnation method with pH adjustment.These catalysts were characterized by X-ray diffraction(XRD),atomic absorption spectrometry(AAS),N2 physisorption and hydrogen temperature programmed reduction(H2-TPR)measurements which reveal that the cubic cagelike(Im3m)pore structure of the parent SBA-16 molecule sieves was well maintained throughout the synthesis.After introduction of Cu,a different CuO dispersion exists on these catalysts.The CuO/SBA-16 prepared by modified impregnation method has a single highly dispersed CuO which is considered as a highly efficient species for hydroxylation of phenol withH2O2.CuO/SBA-16 prepared by the conventional impregnation method shows the presence of bulk CuO species which is undesirable for this reaction.展开更多
文摘A series of cerium phosphate catalysts with different crystal phases were synthesized by hydrothermal method and co-precipitation method.Hexagonal cerium phosphate(CePO_(4)-H)shows better NH_(3)-SCR denitration activity than monoclinic cerium phosphate(CePO_(4)-M)and mixed phases of CePO_(4)-H and CePO_(4)-M.Moreover,CePO_(4)-H also exhibits excellent activity stability with stream time and cycling stability.Various characterizations were carried out to explain the effects of different crystal phases of CePO_(4)on the activity.Among these catalysts,CePO_(4)-H has much stronger surface acidity that is conducive to the adsorption and activation of NH_(3),and more surface adsorbed oxygen species that can effectively improve SCR activity.In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)were performed to investigate the adsorption and reaction of NH_(3)and NO_(x)on CePO_(4)-H and CePO_(4)-M,and the results suggest that the better activity over CePO_(4)-H follows mainly the Eley-Rideal mechanism in the activity temperature window(300-500℃)with 100%NO conversion.
基金the Science and Technology Foundation of Office of Education of Heilongjiang Province(Grant No.10551251).
文摘CuO/SBA-16 catalysts were prepared by two different routes–the conventional impregnation method and the modified impregnation method with pH adjustment.These catalysts were characterized by X-ray diffraction(XRD),atomic absorption spectrometry(AAS),N2 physisorption and hydrogen temperature programmed reduction(H2-TPR)measurements which reveal that the cubic cagelike(Im3m)pore structure of the parent SBA-16 molecule sieves was well maintained throughout the synthesis.After introduction of Cu,a different CuO dispersion exists on these catalysts.The CuO/SBA-16 prepared by modified impregnation method has a single highly dispersed CuO which is considered as a highly efficient species for hydroxylation of phenol withH2O2.CuO/SBA-16 prepared by the conventional impregnation method shows the presence of bulk CuO species which is undesirable for this reaction.
