Wang Ye, a professor at Xiamen University, and the Cheng June project group, discovered and used the high-efficiency activation of lignin specific chemical bonds by quantum dot catalysts, and for the first time realized the complete transformation of native lignin under mild conditions under visible light irradiation.
Related results were recently published online in "Nature-catalysis." Lignin is the source of the most abundant aromatic compounds in nature, the β-o-4 bond is 60% in the chemical bond chain structure, and the selective cutting off of the key is the key to obtain the high value aromatic compound monomer.
It is found that under visible light irradiation, CDs nanoparticles can effectively catalyze the broken bonds of β-o-4 in lignin model molecules at room temperature, which is more efficient than the traditional high temperature thermal catalysis system.
However, when real biomass (birch) is used as raw material, CDs nanoparticles are largely unable to catalyze the transformation of native lignin. The main reason is that native lignin is almost insoluble in any solvent under mild conditions, so that reactants (native lignin) and multiphase catalysts can not achieve effective contact at the molecular level. The researchers found and made full use of the colloidal properties of CDs nanoparticles quantum dots to make quantum dots highly dispersed or approximately soluble in solvents by regulating the surfactants of quantum dots and the solvents used. The results showed that 84% of the theoretical aromatic compound monomer yield was obtained under visible light irradiation. The hydrolysis of hemicellulose was further catalyzed by weak acid, and the yield of xylose was obtained by 84%.
