Photocatalyst CdS for efficient cleavage of lignin CO bonds in micellar aqueous medium

Photocatalytic cleavage of lignin C O bonds is a promising way to depolymerize lignin into aromatic value-added chemicals. However, the dispersibility of lignin in solvents and photocatalytic efficiency still face great challenges. Here, a micelle aqueous medium (CTAB-15) composed of hexadecyl trimethyl ammonium bromide and water was successfully prepared. 2-phenoxy-1-phenylethanol (lignin model compounds, PPol) and dioxanesolv poplar lignin have a good dispersion in CTAB-15. Compared to the previous reports, the highest photocatalytic efficiency can be obtained under optimal conditions by using the photocatalyst CdS. The main products formed by photocatalytic cleavage of lignin C O bonds are phenols and ketones. Mechanism studies show that CTAB-15 can provide sufficient hydrogen by photo-driven dissociation of water for photocatalytic cleavage of lignin C O bonds, which is critical to rapidly improving photocatalytic efficiency. The hydrogen, which is used to form acetophenone, comes from H 2 O and PPol. However, the hydrogen needed to form phenol comes only from PPol itself. In addition, the photocatalytic reaction follows a photogenerated electron-hole coupled redox process. This work develops a new direction for promoting the high-value utilization of lignin.