Crystal Phase Reconstruction of Bi-(N-C)/Bi(OH)3-Bi2O3 for Selective Cleavage of Lignin Cꞵ-O-4 Bond via Fluidized Electrocatalysis

Developing efficient systems for directional lignin depolymerization via cleaving the aryl ether bonds to produce high-value-added chemicals is intriguing but remains challenging. Herein, we report a crystal phase reconstruction strategy for the synthesis of heterogeneous Bi-(Et3N)0.3 catalyst with rich defect sites and high-valence Bi species, which exhibits promising performance towards the fluidized electrocatalytic hydrogenation (FECH) of lignin-derived 2-phenoxy-1-phenylethanol with full conversion and up to 60.7% yield of phenol formation. Experimental and theoretical results confirm that the high-valence Bi species is beneficial in promoting the rapid activation of the protons, while the rich-defect sites derived from the crystal phase reconstruction between Bi-O and Bi-N-C coordination optimize the adsorption-activation of oxygen-containing intermediates. Moreover, by manipulating the variation of current density, the dissociation efficiency of protons and the enrichment degree of the electron-rich ([PW10VIW2VO40]5−) groups of the phosphotungstic acid (HPW) electrolyte were modulated, enabling the controllable switching of the phenol generation pathway. This study elucidates that the synergy between defect sites and high-valence Bi metals could advance the rational design of efficient electrocatalytic systems for the directional and efficient cleavage of lignin Cꞵ-O-4 bonds for high-value-added chemicals.