| With the rapid development of human society,people rely on energy more than ever before.As one of the three primary fossil fuels,the exploitation of natural gas is increasing,which requires clean and efficient utilization of methane.Dry reforming of methane(DRM)uses CH4 and CO2 as feedstocks to produce syngas so that DRM can mitigate the adverse environmental effect during the energy utilization,since both CH4 and CO2 are major greenhouse gases.First,this dissertation describes the design and preparation of a novel Ni/La2O3 catalyst for DRM.The results showed that La2O3 derived from the La2O2CO3 precursor can highly disperse Ni particles on it.Additionally,the nanorod-shaped support could provide more medium-strength basic sites to facilitate CO2 adsorption and activation on its surface.The enhanced metal-support interaction restricted the sintering of nickel particles under harsh reaction conditions.Coke evolution on the catalysts was also investigated to understand coke formation mechanism and the role of La2O2CO3 in coke elimination.Second,this dissertation stands on the viewpoint of lanthanum oxide and aims to provide new insight about the influence of Ce addition towards the CO2 adsorption and activation on La2O3.For Ce-La solid solution,it is well-known that La dopant into lattice of ceria can largely promote the formation of oxygen vacancy on ceria and enhance the oxygen storage/release capacity of ceria.Ce addition can promote the formation of bidentate carbonate on La2O3 and improve the activity of bidentate carbonate.In addition,Ce addition can adjust the ratio of bidentate and monodentate carbonate,and the latter will influence the ratio of hexagonal La2O2CO3 and monoclinic La2O2CO3 on the mixed oxide.Here,DRM is used as a probe reaction to examine the coke elimination performance of Ce-La mixed oxide.When Ce/La ratio reaches at 0.15,Ce-La mixed oxide has the highest amount of strong-strength basic sites and exhibits the best coke elimination performance. |
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