ZIF-67-derived Zr@Co/C600 core-shell catalyst enhances efficient ethanolysis of Xiwan subbituminous coal to produce hydrocarbon-rich oil

The conversion of low-rank coal into hydrocarbon-rich oil through catalytic ethanolysis (CE) not only facilitates its efficient utilization but also mitigates dependence on conventional coal liquefaction technologies, which are typically associated with high temperature, high pressure, and substantial energy consumption. Nevertheless, the primary challenge in transforming low-rank coal into hydrocarbon-rich oil via CE is to maximize the yield of ethanol-soluble products while achieving efficient oxygen removal. In this study, we present a composite catalyst, Zr@Co/C 600 , synthesized via the pyrolysis of ZIF-67. The catalyst features a unique structure wherein uniformly dispersed Co species are anchored on an N-doped porous carbon core and encapsulated within a ZrO 2 shell. The porous carbon matrix in Zr@Co/C 600 significantly enhances the dispersion of Co species, while the ZrO 2 shell offers abundant strong acidic sites that facilitate the cleavage of >C–O– bonds. Moreover, the shell effectively suppresses Co leaching and agglomeration during the reaction, thereby substantially improving the recyclability and long-term stability of the catalyst. Under the catalytic action of Zr@Co/C 600 , ethanol is efficiently activated to generate reactive radicals such as H·, ·CH 2 CH 3 , and ·OCH 2 CH 3 . These radicals target the >C–O– bonds in Xiwan subbituminous coal (XWC), promoting oxygen removal and ultimately yielding 25.1 wt% of soluble products and 55.4 % hydrocarbons. Based on experimental investigations and computational simulations, we identify H· as the key radical responsible for cleaving the >C–O– bonds in benzyloxybenzene (BOB), and further propose a plausible reaction pathway for the CE of BOB. • A novel catalyst featuring a ZrO 2 shell and a ZiF-67 core with strong acidic sites. • Ethanol can be activated into H·, ·CH 2 CH 3 , and ·OCH 2 CH 3 species over Zr@Co/C 600 . • Identifies H· as key to selective C-O cleavage by experiments and DFT calculations. • CE boosted XWC soluble yield by 106 %, with hydrocarbons reaching 55.4 %.