Catalytic conversion of one-carbon (C1) molecules, such as CO, CO 2 , CH 4 , and CH 3 OH, into fuels and value-added chemicals is a vitally important process in the chemical industry because of its close correlation to energy and environmental implications. However, the selectivity control, energy saving, and emission reduction remain great challenges for C1 chemistry due to the complex and changeable conversion processes. Herein, we briefly summarize recent advances and milestones in conversion of C1 molecules in the last decade, particularly focusing on the new reaction processes, including thermal-driven reactions, such as direct methane to ethylene, CO 2 hydrogenation, and oxide-zeolite process for syngas conversion, and mild-condition conversion processes, such as roomtemperature methane conversion, electrochemical water-gas shift, electrocatalytic CO reduction to ethylene, and light-driven methanol to ethylene glycol. The challenges and prospects are also fully discussed toward the C1 chemistry for the basic and applied research in the future.

High-density polycycloalkanes were first produced with cellulose by a highly integrated route that features a selective hydrogenolysis of cellulose to 2,5hexanedione under mild conditions, followed by the direct synthesis of polycycloalkanes with 2,5-hexanedione and hydrogen over a dual-bed catalyst system. The polycycloalkane mixture as obtained has a high density (0.88 g mL À1 ) and low freezing point (225 K). In real application, they can be used as advanced aviation fuel or additives to improve the volumetric heat values of conventional aviation fuels.