Pretreatment-Regulated Structural Evolution and Dynamic Cu–CoOx Interfaces for Enhanced C–O Bond Hydrogenolysis of Zhaotong Lignite

Abstract

Efficient depolymerization of lignite remains challenging owing to both its structural complexity and the high stability of oxygen-containing bridge linkages. Herein, low-temperature pyrolysis and oxidative pretreatments were employed to regulate oxygen-containing structures and enhance the hydrogenolysis reactivity of Zhaotong lignite (ZT). These pretreatments promoted the structural evolution of lignite, activated oxygen-containing bridge structures, and suppressed the recondensation of reactive intermediates, thereby facilitating subsequent depolymerization reactions. A CuCoOx catalyst capable of dynamic in situ reconstruction was introduced for catalytic hydrogenolysis. Under reaction conditions, partial reduction of CuCoOx generated reconstructed Cu0-CoOx interfacial active sites, where the synergistic interaction between metallic Cu and defect-rich CoOx promoted H2 activation and selective C–O bond cleavage. Density functional theory (DFT) calculations further revealed that interfacial electron redistribution at the Cu cluster/Vo-Co3O4 (311) interface facilitated H2 activation and stabilized reactive hydrogen species. These findings provide new mechanistic insights into pretreatment-regulated and interface-controlled hydrogenolysis pathways for the efficient valorization of low-rank coal.