A Mini-review: Catalytic Hydroconversion of Organic Matter in Low-Rank Coals and Transference of Active Hydrogen

Directional conversion of organic matter in coals has been a promising protocol for transforming coals into high-value chemicals, high-performance carbon materials, and high-density liquid fuels. Low-rank coals (LRCs) exhibit overwhelming advantages as feedstocks for liquid fuels and valuable chemicals, due to their higher H/C atom ratio, volatile, and contents of oxygen-functional groups. Organic matter in LRCs is rich in condensed aromatic rings, which are connected by various types of C─C/〉C─O bridge bonds, some alkyl side chains and heteroatom-containing groups. How to effectively cut the large molecules into small organic molecules with high value-added chemicals? This is the core scientific problem in the coal conversion technologies. Catalytic hydroconversion (CHC) is one of the effective methods, containing catalytic hydrocracking/hydrorefining, for converting coals to clean liquid fuels. Catalyst plays an important role in activating hydrogen, promoting directed hydroconversion, and removing heteroatoms, which directly determines the reaction system and product quality. In this perspective, we intend to give readers a survey of the research advances in the catalytic hydroconversion of organic matter in low-rank coals and transference of active hydrogen. Finally, some perspectives are prospected for future developments and selective CHC of organic matter in coals and high value-added clean utilization of coals.