The Study On Fabrication Of Supported Sulfided Mo-based Catalyst For Higher Alcohols Synthesis Via Syngas

Higher alcohols,as a kind of important intermediate products,is of great commercial value.It is promising to produce higher alcohols directly from synthesis gas.This thesis focused on enhancing the HAS activity and alcohols selectivity of Mo-based catalyst via novel preparation method and modification of supports.A series of MMO supported Mo-based catalysts with tunable metal-support interaction and MoS₂ morphology were prepared with CTAB encapsulated molybdenum precursor.The as-prepared catalysts exhibit promoted activity and higher alcohols selectivity,whose STY reaches 3.2 and 1.5 times of that of IM-K,Ni-30Mo/MMO and co-IM-K,Ni-30Mo/MMO,respectively.The well dispersion of Mo species and the control over stacking degree along with the size of MoS₂ crystals were realized through tuning the metal-support interaction.Abundant active Mo atoms at the edge sites were exposed and interacted with Ni,which increased the amount of highly dispersed and effectively contacted dual active sites NiS_x and Ni-KMoS_x,endowed the synergism of dual active sites,and thus,provided the catalysts with high activity and exceptional higher alcohols selectivity.K-promoted molybdenum catalysts supported on NiMgAl trimetal mixed metal oxides?MMO?were prepared through CTAB encapsulated Mo-precursor strategy and tested for the higher alcohols synthesis.The alkalinity and acidity of MMOs are tuned by the alkaline etching,which further effect the textural properties,metal-support interaction and sulfidation degree of the synthesized materials.A proper balance between acidity and alkalinity in the catalysts can promote the HAS performance on Mo based catalyst in both activity and alcohol selectivity.The formation of C₂₊alcohols can be boosted via adol condensation via suppressed acidity and increased amount of basic sites.The enriched surface anion groups can also enhance the reducibility and dispersion of Mo species and have a positive impact on the HAS activity.The alkaline etching successfully promoted higher space time yield of C₂₊alcohols over unit mass of molybdenum.