A Trade-Off between Light Absorption and Catalytic Sites: The Effect of Polymerization Degree of Graphitic Carbon Nitride on Its Photocatalytic Activity

作者：Tong Li, Nan Liu, Jing Liu, Bo Lai, Shuangtao Yuan, Rongrong Li, Xiaojia Zhao, Xiaoguang Luo, Dongli Yu, Yuanchun Zhao · 发表于：The Journal of Physical Chemistry C · 年份：2025 · DOI：10.1021/acs.jpcc.5c03241 · 被引用次数：10 · 研究领域：Advanced Photocatalysis Techniques、Gas Sensing Nanomaterials and Sensors、Ga2O3 and related materials

Polymeric graphitic carbon nitride (g-CN) has attracted tremendous attention as a promising visible-light-responsive photocatalyst. Although the degree of polymerization (DP) of g-CN is the foundation to determine its physicochemical properties, its effect on the photocatalytic activity still remains elusive. Herein, a well-controlled synthetic route was employed to prepare pristine g-CN with DPs regulated to a certain extent but excludes additional factors like heteroatom doping, surface area, and structural modification. In particular, we updated the X-ray photoelectron spectroscopy analysis based on the recent theoretical/experimental results, providing a reasonable identification of specific chemical bonding states that are in line with the corresponding DP variations. This allows us to correlate the DP evolution of pristine g-CN with its photocatalytic activity, unveiling the trade-off mechanism between visible-light absorption and defective catalytic sites. The average DPs of the synthesized g-CN samples have been roughly estimated based on the molecular formula of (C 6 N 7 ) n (NH 2 ) n +2 (NH) n −1, which is supposed to be adjusted in the range of 4 ≤ n ≤ 10 by changing the condensation time from 1 to 12 h. The sample thermally condensed for 4 h exhibits an optimal visible-light activity for degradation of dyes, with a rather low average DP estimated to be n = 4–5.