Value-added conversion of lignin based on inorganic−organic dual-ligand-regulated CdSe@CdS nanorods

In lignin valorization systems, CdSe@CdS nanorods exhibit exceptional photocatalytic performance, where precise control over the rates of oxidation and reduction reactions is crucial. This study introduces a ligand modulation strategy that involves the incorporation of mercaptopropionic acid (MPA) and hexafluorophosphate (PF₆⁻) onto the surface of the nanorods to achieve a balanced redox reaction profile. The inorganic PF₆⁻ ligand primarily promotes reduction reactions, whereas MPA enhances hole transfer. By optimizing the distribution ratio of these ligands, the study achieved a significant enhancement in photocatalytic efficiency, resulting in a 94 % conversion rate for 2-phenoxy-1-phenylethanol (PP-ol) and yields of 67 % and 66 % for phenol and acetophenone, respectively. The distinct roles of MPA and PF₆⁻ can be attributed to their respective spatial site resistances, electrostatic interactions, and surface passivation characteristics. MPA, with its larger spatial resistance, stabilizes and extends hole lifetimes, thereby enhancing hole transfer efficiency. In contrast, PF₆⁻ exhibits lower spatial resistance and stronger electrostatic effects, which facilitate accelerated electron transfer. Furthermore, the ligands optimize the transport pathways for both electrons and holes on the nanorod surface through passivation. This ligand design strategy provides valuable insights for the development of efficient nanorod photocatalysts aimed at biomass valorization.