Applications of metals and metal sulphides in catalytic hydrocracking of coal and their related model compounds

Coal liquefaction is a promising approach to reduce pollution comparing to combustion. Industrialisation of indirect coal liquefaction (ICL) has succeeded by Sasol in South Africa. In ICL process, coal is treated as resource of carbon and hydrogen rather than aromatic compounds. Nevertheless, the percent of chemicals in the products of Sasol reaches up to /3. Chemicals oriented direct coal liquefaction (DCL) is superior to ICL considering energy efficiency and structural characteristics of coal, especially when the target products are aromatic compounds. The key to achieve it is highly active and selective catalysts for DCL. Herein, metal catalysts employed in DCL and coal-related model compounds are viewed. The existing problems and road maps of metal catalysts for DCL are pointed out. Bi- or multi-metal catalysts on specific supporter with high activity and selectivity are candidate catalysts for DCL. Besides, reaction mechanisms are also discussed. [Received: July 10, 2014; Accepted: January 14, 2015]