Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
School of Materials Science and Engineering, Hunan University, Changsha 410082, China.
Nanoscale. 2019 Sep 21;11(35):16393-16405. doi: 10.1039/c9nr05413h. Epub 2019 Aug 22.
Polymeric carbon nitride (CN) is a promising metal-free catalyst plagued by a low intrinsic activity. Herein, a novel strategy based on controllable in situ surface engineering and morphology was developed to synergistically boost the catalytic activity of CN by tuning the hydroxyl groups on its surface and constructing a unique nanostructure. The controllable introduction of hydroxyl groups on CN nanoshells, prepared by the thermal condensation of oxygen-containing supramolecular precursors formed in water, led to spatial separation of the HOMO and LUMO, and effective exciton dissociation, as verified by experiments and ab initio calculations. Furthermore, the hollow hemispherical nanoshell endowed more exposed active sites, optimal mass transport, and dynamic modulations. The optimized hollow hemispherical CN nanoshells exhibited remarkable catalytic activity, with a photoelectrocatalytic OER overpotential of about 330 mV at a current density of 10 mA cm, outperforming state-of-the-art precious-metal catalyst IrO. High activity for the visible-light photocatalytic HER and pollutant degradation were also observed. This study proposes that, through rational surface group modification, a polymer material with high catalytic activity can be practically realized, which is promising for the design of efficient metal-free catalysts.
聚合物氮化碳（CN）是一种很有前途的无金属催化剂，但存在固有活性低的问题。本文提出了一种基于可控原位表面工程和形态的新策略，通过调节表面的羟基基团和构建独特的纳米结构，协同提高 CN 的催化活性。通过在含氧超分子前体在水中形成的热缩聚制备的 CN 纳米壳上可控地引入羟基基团，实验和从头算计算验证了 HOMO 和 LUMO 的空间分离和有效的激子解离。此外，中空半球形纳米壳赋予了更多暴露的活性位点、最佳的质量传输和动态调节。优化后的中空半球形 CN 纳米壳表现出优异的光催化 OER 活性，在电流密度为 10 mA cm 时的光电催化 OER 过电位约为 330 mV，优于最先进的贵金属催化剂 IrO。还观察到可见光光催化 HER 和污染物降解的高活性。该研究提出，通过合理的表面基团修饰，可以实现具有高催化活性的聚合物材料，这为设计高效的无金属催化剂提供了新的思路。
