Efficient oxidative cleavage of lignin C-C model compound using MOF-derived Cobalt/Nickel sulfide heterostructures

Producing fine chemicals by electrooxidation to replace sluggish oxygen evolution reaction (OER) provides a new opportunity and challenge for the high-value utilization of biomass. The oxidative breakage of the Cα-Cβ bond is an essential part of lignin depolymerization to platform chemicals and is largely dependent on electrocatalysts. Herein, a synthesis strategy is proposed using metal-organic framework (MOF) encapsulation and sulfuration on the nickel foam (NF) substrate. The robust bimetallic sulfides heterostructures, named Co3S4/(α,β)-NiS, showed selectively and efficiently oxidize Cα-Cβ in 2-phenoxy-1-phenylethanol (PPE), a typical β-O-4 model. An ultralow potential of 0.954 V vs RHE is exhibited by [email protected]3S4/(α,β)-NiS for 10 mA cm−2 in alkaline solutions containing PPE, owing to the multiphase active interface and smooth pore channels. A PPE conversion of 93.6% and benzoate yield of 83.8% were reached from the electrooxidation of PPE at 1.414 V vs RHE. Meanwhile, lignin can be effectively cleaved to the main product vanillin. This study develops an inexpensive and stabilized transition metal-based electrocatalyst for lignin upgrading to afford value-added products in the anode side and lower electricity consumption of water splitting.