| dc.description.abstract | Methane dry reforming reaction needs to be carried out at a high temperature due to high activation energy, so that the catalyst would have serious coking. One of the ways to make a breakthrough is to improve the catalyst. The use of Ni/MgO-Al2O3 catalyst, Ni/MgO-Al2O3-AlPO4 catalyst and core-shell catalyst were the effective methods because of their high activity, high selectivity and excellent stability. The first catalyst was Ni/MgO-Al2O3, which Ni was supported on MgO-Al2O3 to improve its metal dispersion, thereby improving its activity and sintering resistance. To improve the Ni/MgO-Al2O3 catalyst, Al2O3-AlPO4 was chosen to replace the Al2O3 in the MgO-Al2O3 support. XRD and N2 sorption analysis were used to characterize the Al2O3-AlPO4 with different aluminum-phosphorus ratios and different calcination temperatures, to compare with Al2O3. It was found that the BET surface area of the Al2O3-AlPO4 (Al/P=5/1, calcined at 700°C) support increases greatly. Therefore, it was used in Ni/MgO-Al2O3-AlPO4 catalyst to effectively increase the surface area of the catalyst, and then increase the methane conversion and stability. The characteristics of Al2O3-AlPO4 (Al/P=5/1, calcined at 700°C) was the best, one can further increase the performance of the Ni/MgO-Al2O3-AlPO4 catalyst. Therefore, MgO-Al2O3-AlPO4 supports and Ni/MgO-Al2O3-AlPO4 catalysts with different aluminum-phosphorus ratios with the same 700°C calcination temperature were used. It was found that the support of MgO-Al2O3-AlPO4 (Al/P=5/1) had good characteristics, it has high BET surface area and BJH adsorption cumulative volume of pores. The other catalyst was with core-shell structure, which the active metal nickel was surrounded by the Al2O3 support. To product this catalyst, there was an ion exchange reaction. Under such reaction, the force between the active metal nickel and the support was 3-D space, which was different from the 2-D space of the conventional catalysts, so that the interaction force between the metal and the support was enhanced. It was beneficial to improve the stability of the catalyst. With the increase of aluminum-nickel ratio, the degree of ion exchange gradually became stronger, so it presented a dense shell, which reduced the desorption average pore diameter, then it would increase the BET surface area and was greater than that of conventional catalysts. | en_US |