BaTiO3-BaAl2O4-Al2O3复合载体的制备、表征及其Ni基催化剂催化CH4/CO2重整反应性能

以十六烷基三甲基溴化胺为结构导向剂,采用溶胶-凝胶法制备了BaTiO3-BaAl2O4-Al2O3复合载体,采用X射线衍射、红外光谱、N2吸附-脱附、透射电子显微镜和H2程序升温还原等技术对复合载体进行了表征,并以CH4/CO2重整制合成气为探针反应,考察了不同Ni/BaTiO3-BaAl2O4-Al2O3催化剂的性能.结果表明,BaTiO3-BaAl2O4-Al2O3复合载体具有多孔织构特性和较高的比表面积,BaTiO3和BaAl2O4以晶粒状态分布在复合载体的内外表面,晶粒尺寸在20～50nm的范围,复合载体孔径为10～20nm.复合载体上BaTiO3和BaAl2O4的引入,适度削弱了Ni/BaTiO3-BaAl2O4-Al2O3催化剂中Ni物种与γ-Al2O3间的强相互作用,抑止了NiAl2O4尖晶石的生成;当载体中Ba(Ti)含量为17.33%时,其负载的Ni催化剂上CH4/CO2重整制合成气反应的活性和稳定性最高.

Preparation and Characterization of BaTiO3-BaAl2O4-Al2O3 Composite Support and Catalytic Performance of Its Nickel-Based Catalyst for CO2 Reforming of Methane

Nickel-based catalyst supported on BaTiO3 possesses higher initial activity for carbon dioxide reforming of methane. However, the specific surface area of the BaTiO3 support is too small, and this restricts its application as a catalyst support. A BaTiO3-BaAl2O4-Al2O3 composite support was prepared by the sol-gel method using hexadecyltrimethylammonium bromide as the structure template. The Ba-TiO3-BaAl2O4-Al2O3 composite was characterized by X-ray diffraction, infrared spectroscopy, N2 adsorption-desorption, transmission electron microscopy, and H2 temperature-programmed reduction. The catalytic performance of the Ni/BaTiO3-BaAl2O4-Al2O3 catalyst was investigated by CO2 reforming of CH4. The results showed that the BaTiO3-BaAl2O4-Al2O3 composite support owns a porous texture and high specific surface area, the BaTiO3 and BaAl2O4 phases, whose crystalline size is in the range of 20–50 nm, exist on the inside and outside surface of the composite support in the form of crystalline particles. The size of micropores of the composite support is 10–20 nm, The presence of both BaTiO3 and BaAl2O4 phases on the surface of the composite support weakens the strong interaction between the nickel species and γ-Al2O3 of the Ni/BaTiO3-BaAl2O4-Al2O3 catalyst, and the possibility of the formation of NiAl2O4 spinel is decreased. The Ni/BaTiO3-BaAl2O4-Al2O3 catalyst with 17.33% Ba content shows the highest activity and excellent stability for CH4 reforming with CO2 to synthesis gas.