Fengxiang Yin

Structural Characterization of Highly Stable Ni/SBA-15 Catalyst and Its Catalytic Performance for Methane Reforming with CO2

Abstract A series of Ni/SBA-15 catalysts with different Ni contents (2.5%–20%) were prepared using an incipient wetness impregnation method. The catalytic properties of the catalysts for methane reforming with carbon dioxide were tested using a continuous-flow fixed-bed quartz reactor. The structure of the catalysts was characterized using X-ray diffraction and N 2 adsorption. The results indicated that the Ni/SBA-15 catalysts led to a higher conversion of CH 4 and CO 2 under the reaction conditions. The 12.5% Ni/SBA-15 catalyst showed highly stable activity at 800°C for 600 h. However, after reaction for 710 h, the conversion of CH 4 and CO 2 decreased by about 50% and 25%, respectively. Coking was the main reason for the deactivation of the Ni/SBA-15 catalysts. At higher reaction temperatures, the mesoporous structure of SBA-15 was not destroyed and the pore walls of SBA-15 could prevent the aggregation of the nickel species. By inserting nickel into SBA-15, a small pore was formed besides the mesopores of SBA-15. The mesoporous structure of SBA-15 was not affected by the nickel species; however, the pore diameter, the pore volume, and the BET surface area decreased.

Preparation of Pd-Based Metal Monolithic Catalysts and a Study of Their Performance in the Catalytic Combustion of Methane

A series of Pd/SBA-15/Al2O3/FeCrAl and Pd/5 wt% Ce(1-x)Zr(x)O2/SBA-15/Al2O3/FeCrAl (x = 0-1) metal monolithic catalysts were prepared and characterized by various techniques. The catalytic activity and the stability of the catalysts for methane combustion were evaluated. All the catalysts retain the SBA-15 mesoporous structure, with PdO being confined in its channels. The results show that the addition of Ce(1-x)Zr(x)O2 as promoters can improve the activity and stability of the catalysts. The stabilities of the metal monolithic catalysts are much better than those of Pd/ SBA-15 particle catalysts. The catalyst with ZrO2 as promoter exhibits the best activity and stability (T90= 395 degrees C), and the conversion of methane remains constant during the 700 h test.

Pd/Ce1- xZrxO2/SBA-15 catalysts : preparation and catalytic properties for methane combustion

A series of Pd/SBA-15 and Pd/Ce1-xZrxO2/SBA-15 (x=0, 0.5, 1) catalysts with different Pd loadings were prepared by the impregnation method. The catalysts were characterized using XRD and TPR techniques. The catalytic performance for the catalytic combustion of methane was investigated. The results showed that both Pd/SBA-15 and Pd/Ce1-xZrxO2/SBA-15 catalysts exhibited an excellent catalytic activity in methane combustion. In the Pd/Ce1-xZrxO2/SBA-15 catalysts, the activity increased with increasing of Zr content. After incorporation of Pd and Ce1-xZrxO2 in the SBA-15 support, all catalysts still possessed ordered hexagonal mesoporous structures. There were the stronger interaction among the Pd and the Ce1-xZrxO2 and the SBA-15 support. The interaction could significantly modify the redox performance and affect the catalytic activity of the catalysts.

Catalytic Combustion of Methane over Co1−xMgxO/Al2O3/FeCrAl Monolithic Catalysts

Abstract A series of Co 1−x Mg x O/Al 2 O 3 /FeCrAl catalysts ( x =0−1) were prepared. The structures of the catalysts were characterized using XRD, SEM, and TPR analyses. The catalytic activity of the catalysts for methane combustion was evaluated in a continuous flow microreactor. The results indicated that the active washcoats adhered well on the FeCrAl foils. The phases in the catalysts were Co 1−x Mg x O solid solutions, α-Al 2 O 3 , and γ-Al 2 O 3 . The surface particle size of the catalysts varied with variations in the molar ratios of Co to Mg. The Co component of the Co 1−x Mg x O/Al 2 O 3 /FeCrAl catalysts played an important role in the catalytic activity for methane combustion. In the Co 1−x Mg x O/Al 2 O 3 /FeCrAl ( x =0.2−0.8), the catalytic activity in terms of x was in the order of 0.5>0.2>0.8 under the experimental conditions. The presence of Mg in these catalysts could promote the thermal stability to a large extent. There were strong interactions between the Co 1−x Mg x O and the Al 2 O 3 /FeCrAl supports.

Catalytic combustion of methane over pd/sba-15/ al2o3/fecral catalysts

A series of Pd/SBA-15 with different Pd loadings and 0.5%Pd/SBA-15/Al 2 O 3 /FeCrAl as well as 0.5%Pd/5%Ce 1-x Zr x O 2 /SBA-15/Al 2 O 3 /FeCrAl (x=0, 0.5, 1) catalysts were prepared and characterized. Their catalytic activity and stability for combustion of methane were investigated. The results showed that Pd/SBA-15 catalysts exhibited an excellent activity, and methane could be combusted completely below 400 °C. The 0.5%Pd/SBA-15/Al 2 O 3 /FeCrAl monolithic catalyst showed a good activity. The activity of 0.5%Pd/5%Ce 1-x Zr x O 2 /SBA-15/Al 2 O 3 /FeCrAl monolithic catalysts was enhanced due to the addition of Ce 1-x Zr x O 2 , and the activity increased with Zr content increasing. The 0.5%Pd/SBA-15 catalyst exhibited a rapid deactivation. However, the 0.5%Pd/SBA-15/Al 2 O 3 /FeCrAl catalyst and 0.5%Pd/5%Ce 1-x Zr x O 2 /SBA-15/ Al 2 O 3 /FeCrAl catalyst were more stable than 0.5%Pd/SBA-15 catalyst. The monolithic catalysts still had a well-defined hexagonal pore structure of SBA-15 when supported on FeCrAl supports.