From catalytic coal liquefaction to CO₂ capture and conversion towards fuels of the future

In keeping with the sprit of Henry Storch award in fuel chemistry, this award lecture will discuss the advances in selected areas of our research on catalytic coal liquefaction for producing liquid fuels and chemicals, on shape-selective synthesis of value-added chemicals from coal-derived aromatics, and on capture and conversion of CO₂ emitted from coal utilization. Coal structure is characterized by aromatic rings that are abundant in various coal-derived liquids from liquefaction, pyrolysis, carbonization, and certain gasification processes. The cyclic structural units in coal offer special advantages in producing advanced liquid fuels such as thermally stable jet fuels for high-speed supersonic and hypersonic aircrafts. New approaches by shape-selective catalysis has become promising for developing value-added chemicals and engineering materials from polycyclic aromatic hydrocarbons that are abundant in coal-derived liquids such as naphthalene, biphenyl, and phenanthrene. In distinct contrast to previous coal conversion research till early 1990s, CO₂ capture has become an important issue for coal utilization without negative impact on the climate change. A new approach called "molecular basket" sorbents (MBS) for CO₂ capture and separation from flue gas of coal-based electric power plants will be introduced. MBS is based on a combination of nano-porous materials and special polymers such as polyethylenimine, which function as high-capacity sorbents for selective CO2 capture and separation. Furthermore, a long-term vision on converting CO₂ into liquid fuels and chemicals using hydrogen generated from water with renewable energy. The world will likely continue to rely on liquid transportation fuels in the foreseeable future. Fuel chemistry and catalysis coupled with material science, chemical and engineering sciences can play a major role in addressing global energy challenges, and in building the bridge to sustainable energy system in the future.