Efficiently hydrogenolysis of aromatic ether C-O bonds in lignite and model compounds over carbon-coated NiCo bimetallic catalyst

Cleaving the aromatic ether C-O bonds of lignite through catalytic hydroconversion (CHC) presents a significant challenge for producing organic chemicals and clean liquid fuels, which are vital for a sustainable future. In this study, we employed a sacrificial template-self-recovery strategy to synthesize highly dispersed and carbon-coated bimetallic catalysts MCo/C (M = Fe, Cu, Ni) for the CHC of Naomaohu coal (NMHC) and lignite-related model compounds (LRMCs). The carbon-coated NiCo bimetallic alloy catalysts, benefiting from the high dispersity of the active components and the synergistic effect between Ni and Co, exhibited excellent hydrogenolysis activity towards diphenyl ether (DPE). DPE conversion reached 100 % over Ni₃Co₁/C under optimal conditions (120 °C, 2 MPa H₂, 2 h). Moreover, Ni₃Co₁/C significantly increased the content of arenes and alkanes while reducing the content of oxygen-containing compounds in the NMHC soluble portion (SP), demonstrating its efficient catalytic hydrogenolysis and hydrodeoxygenation capabilities. Density Functional Theory (DFT) calculations revealed that the Ni₃Co₁/C catalyst could activate H₂ to generate hydrogen radicals and diatomic active hydrogen, which are the primary hydrogen species involved in the reaction and affect the CHC of DPE. The experimental results can provide a reference for the conversion of lignite into clean liquid fuels.