Harnessing the Synergistic Power of Ce2S3/TiO2 S-Scheme Heterojunctions for Profound C–O Bond Cleavage in Lignin Model Compounds

In the context of achieving carbon neutrality, converting lignin-derived molecules into high-value products through photocatalytic technology provides an environmentally friendly pathway. Establishing energy-efficient processes for converting lignin derivatives requires the construction of highly active and selective photocatalysts. However, enhancing the efficiency and selectivity of photocatalysts for lignin degradation poses an ongoing challenge due to discrepancies in the redox potential and the rapid recombination of photogenerated carriers. To address these significant obstacles, we devised an innovative strategy by developing a Ce2S3 nanoparticle-anchored TiO2 nanorod (Ce2S3/TiO2). This advanced photocatalyst with the S-scheme heterojunction, enabling simultaneous control of carrier dynamics and band structure, was used to study the photocatalytic degradation of the lignin model compound 2-phenoxy-1-acetophenone. Moreover, the photocatalyst can cleave the Cβ-O-4 bond selectively to convert the lignin model compound 2-phenoxy-1-acetophenone into phenol and acetophenone under visible-light irradiation. The yields are up to 94 and 80%, respectively, and 94 or 1.4 times greater than those obtained by pure TiO2 or Ce2S3 individually. In addition, our study for the increased activity in Ce2S3/TiO2 based on density functional theory calculations emphasizes the pivotal role of the S-scheme heterojunction generated between Ce2S3 and TiO2. This heterojunction significantly enhances carrier separation efficiency, thereby augmenting the efficacy of the photocatalytic process. The findings furnish valuable insights for developing advanced photocatalytic systems tailored to the efficient depolymerization of Cβ-O-4 bonds in lignin.