A Research Of Co Promoted K/MoS₂ Catalyst For CO Hydrogenation To Higher Alcohols

With the increasing demands for mobile fuel and environmentally benign, much attention has been paid to higher alcohol synthesis from coal or natural gas via syngas due to its properties as the gasoline blend or alternative motor fuel. Among the catalytic systems for higher alcohol synthesis, molybdenum-based catalysts appeared to be promising for its higher activity and sulfur-resistant property, and the addition of transition metals was widely investigated in order to improve the activity and the selectivity and the C2+ alcohols content. In the present work, Co modified K/MoS2 catalyst was studied in higher alcohol synthesis, the catalytic performance and the catalysis mechanism were discussed as well.The following results were summarized in this thesis:1. Co had the ability of promoting the carbon chain growth, which resulted in high C2+ alcohols content in the liquid products. Co mainly existed in Co-Mo-S phase on K/MoS2 surface, which produced perfect synergetic effect between Co and Mo.2. Based on much research for the promotion influenced by the methods of Co introduction, we exploited a new catalyst preparation method-co-precipitation under neutral environment, which could guarantee Co uniformly dispersing on the surface of catalyst in Co-Mo-S phase and effectively improve the performance for alcohols synthesis.3. Meanwhile we triumphantly utilized the ultrasonic technology to produce high performance Co/K/MoS2 catalyst in non-water environment, which was a breakthrough in this field. This new preparation method not only carried out the preparation process in the green way and under control, but also developed sonochemistry in synthetic field.4. We introduced Cu to further modify Co/K/MoS2 catalyst, which was a new type of MoS2-based catalyst with higher alcohol production and C2+OH selectivity. The additive of Cu made Co well dispersed on catalyst surface, which suppress the by-reaction of methanation.5. At last, we built a mold (Co9S8 and Co-Mo-S phase co-exist) for catalyst surface in order to clarify the well performance of Co/K/MoS2 catalyst, and supposed a unique mechanism for alcohols synthesis accord with surface mold of catalyst.