MnO_x/Al_2O_3 and MnO_x/ZrO_2-Al_2O_3 catalysts were prepared by incipientwetness impregnation of Mn(CH_3COO)_2 on the corresponding supports, followed by thecharacterization using X-ray diffraction (XRD), temperature...MnO_x/Al_2O_3 and MnO_x/ZrO_2-Al_2O_3 catalysts were prepared by incipientwetness impregnation of Mn(CH_3COO)_2 on the corresponding supports, followed by thecharacterization using X-ray diffraction (XRD), temperature programmed reduction (TPR) and BETsurface area techniques. The result shows the BET surface area of ZrO_2-Al_2O_3 is lower than thatof Al_2O_3 due to the loading of ZrO_2. However the resulted MnO_x/ZrO_2-Al_2O_3 catalyst exhibitshigher activity for methane combustion than MnO_x/Al_2O_3, because the addition of ZrO_2 ontoAl_2O_3 is beneficial for the dispersion of Mn species and the improvement of the lattice oxygenactivity in MnO_x, subsequently the activation of methane during combustion. The optimum loading ofZr in MnO_x/ZrO_2-Al_2O_3 is in the range of 5%-10% correlated with the calcination temperatures ofcatalyst supports.展开更多
Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst support.The performance of the catalysts was tested to study the effect o...Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst support.The performance of the catalysts was tested to study the effect of support on Mn-based catalyst activity.Performance of the catalysts followed as Mn_(0.4)/Al>Mn_(0.2)/Al>Mn_(0.4)/Ti>Mn_(0.2)/Ti>MnO_(x)>Al_(2)O_(3)on the whole,indicating the synergism of MnO_(x)and Al_(2)O_(3)for NO catalytic oxidation.Results were analyzed according to characterization data.Adsorbed oxygen on catalyst rather than lattice oxygen was detected as the active oxidizer for NO oxidation.As catalyst support,Al_(2)O_(3)provided more sites to carry surface adsorbed oxygen than TiO_(2),resulting in the presence of more active oxygen on Mn O_(x)/Al_(2)O_(3)than on MnO_(x)/TiO_(2).Moreover,MnO_(x)/Al_(2)O_(3)possessed high surface area and pore volume,which greatly benefited the adsorption of NO on catalyst and further favored the oxidation of NO by active oxygen.All these advantages helped Mn_(0.4)/Al exhibited the best catalytic efficiency.展开更多
基金This work was financially supported by Shandong Provincial Department of Science and Technology(project number:981206403)and the State Key Laboratory of Coal Conversion at Institute of Coal Chemistry of CAS(2002-2003)
文摘MnO_x/Al_2O_3 and MnO_x/ZrO_2-Al_2O_3 catalysts were prepared by incipientwetness impregnation of Mn(CH_3COO)_2 on the corresponding supports, followed by thecharacterization using X-ray diffraction (XRD), temperature programmed reduction (TPR) and BETsurface area techniques. The result shows the BET surface area of ZrO_2-Al_2O_3 is lower than thatof Al_2O_3 due to the loading of ZrO_2. However the resulted MnO_x/ZrO_2-Al_2O_3 catalyst exhibitshigher activity for methane combustion than MnO_x/Al_2O_3, because the addition of ZrO_2 ontoAl_2O_3 is beneficial for the dispersion of Mn species and the improvement of the lattice oxygenactivity in MnO_x, subsequently the activation of methane during combustion. The optimum loading ofZr in MnO_x/ZrO_2-Al_2O_3 is in the range of 5%-10% correlated with the calcination temperatures ofcatalyst supports.
基金supported by the National Natural Science Foundation of China(51906193)the Fundamental Research Funds for the Central Universities(xjh012019013)+1 种基金the Basic Research Program of Natural Science in Shaanxi Province(2020JQ-039)support from Young Talent Support Program of Xi'an Association for Science and Technology。
文摘Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst support.The performance of the catalysts was tested to study the effect of support on Mn-based catalyst activity.Performance of the catalysts followed as Mn_(0.4)/Al>Mn_(0.2)/Al>Mn_(0.4)/Ti>Mn_(0.2)/Ti>MnO_(x)>Al_(2)O_(3)on the whole,indicating the synergism of MnO_(x)and Al_(2)O_(3)for NO catalytic oxidation.Results were analyzed according to characterization data.Adsorbed oxygen on catalyst rather than lattice oxygen was detected as the active oxidizer for NO oxidation.As catalyst support,Al_(2)O_(3)provided more sites to carry surface adsorbed oxygen than TiO_(2),resulting in the presence of more active oxygen on Mn O_(x)/Al_(2)O_(3)than on MnO_(x)/TiO_(2).Moreover,MnO_(x)/Al_(2)O_(3)possessed high surface area and pore volume,which greatly benefited the adsorption of NO on catalyst and further favored the oxidation of NO by active oxygen.All these advantages helped Mn_(0.4)/Al exhibited the best catalytic efficiency.
