Modification of G-C3N4 by the Surface Alkalinization Method and Its Photocatalytic Depolymerization of Lignin.
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-07-17 |
| Journal | PubMed |
| Authors | Zhongmin Ma, Ling Zhang, Lihua Zang, Fei Yu |
| Institutions | Qilu University of Technology, Shandong Academy of Sciences |
Abstract
Section titled āAbstractāThe efficient depolymerization of lignin has become a key challenge in the preparation of high-value-added chemicals. Graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>)-based photocatalytic system shows potential due to its mild and green characteristics over other depolymerization methods. However, its inherent defects, such as a wide band gap and rapid carrier recombination, severely limit its catalytic performance. In this paper, a g-C<sub>3</sub>N<sub>4</sub> modification strategy of Kāŗ doping and surface alkalinization is proposed, which is firstly applied to the photocatalytic depolymerization of the lignin Ī²-O-4 model compound (2-phenoxy-1-phenylethanol). Kāŗ doping is achieved by introducing KCl in the precursor thermal polymerization stage to weaken the edge structure strength of g-C<sub>3</sub>N<sub>4</sub>, and post-treatment with KOH solution is combined to optimize the surface basic groups. The structural/compositional evolution of the materials was analyzed by XRD, FTIR, and XPS. The morphology/element distribution was visualized by SEM-EDS, and the optoelectronic properties were evaluated by UV-vis DRS, PL, EIS, and transient photocurrent (TPC). Kāŗ doping and surface alkalinization synergistically regulate the layered structure of the material, significantly increase the specific surface area, introduce nitrogen vacancies and hydroxyl functional groups, effectively narrow the band gap (optimized to 2.35 eV), and inhibit the recombination of photogenerated carriers by forming electron capture centers. Photocatalytic experiments show that the alkalinized g-C<sub>3</sub>N<sub>4</sub> can completely depolymerize 2-phenoxy-1-phenylethanol with tunable product selectivity. By adjusting reaction time and catalyst dosage, the dominant product can be shifted from benzaldehyde (up to 77.28% selectivity) to benzoic acid, demonstrating precise control over oxidation degree. Mechanistic analysis shows that the surface alkaline sites synergistically optimize the C<sub>Ī²</sub>-O bond breakage path by enhancing substrate adsorption and promoting the generation of active oxygen species (Ā·OH, Ā·O<sub>2</sub><sup>-</sup>). This study provides a new idea for the efficient photocatalytic depolymerization of lignin and lays an experimental foundation for the interface engineering and band regulation strategies of g-C<sub>3</sub>N<sub>4</sub>-based catalysts.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal SourceāReferences
Section titled āReferencesā- 2020 - Lignin as a potential source of high-added value compounds: A review [Crossref]
- 2019 - Lignin utilization: A review of lignin depolymerization from various aspects [Crossref]
- 2018 - Advancement in technologies for the depolymerization of lignin [Crossref]
- 2022 - Photocatalytic depolymerization of native lignin toward chemically recyclable polymer networks [Crossref]
- 2020 - Photocatalytic transformations of lignocellulosic biomass into chemicals [Crossref]
- 2019 - Visible-light-induced oxidative lignin C-C bond cleavage to aldehydes using vanadium catalysts [Crossref]
- 2025 - A mini review on photocatalytic lignin conversion into monomeric aromatic compounds [Crossref]
- 2020 - CeCl3-promoted simultaneous photocatalytic cleavage and amination of CĪ±-CĪ² bond in lignin model compounds and native lignin [Crossref]
- 2019 - Selective C-O bond cleavage of lignin systems and polymers enabled by sequential palladium-catalyzed aerobic oxidation and visible-light photoredox catalysis [Crossref]