Highly selective hydrogenolysis of lignin -O-4 models by a coupled polyoxometalate/CdS photocatalytic system

Selective hydrogenolysis of abundant C-O bonds of beta-O-4 linkages in natural lignin or lignin models has been considered as a key strategy for the generation of value-added organic chemicals. Herein, we report a mild, efficient, and selective photocatalytic strategy for hydrogenolytic cleavage of lignin beta-O-4 models by using Ni-containing polyoxometalate (POM) catalysts and CdS quantum dots. Upon blue LED light irradiation, the present photocatalytic system can effectively transform various lignin beta-O-4 models to the corresponding hydrogenolysis products (phenols and ketones) with >95% conversion and >93% product selectivity. A tentative photocatalytic mechanism is proposed based on various experimental and spectroscopic analyses. The facile strategy presented in our work could be extended to the photocatalytic preparation of various value-added chemicals from natural biomass or other biomass derivatives in the near future.