Wang Yuelin, Ngoc Pham Thanh, Tian Yu, Morikawa Yoshitada, Yan Likai
Institute of Functional Material Chemistry, Key Laboratory of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, PR China; Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan.
Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan.
J Colloid Interface Sci. 2021 Mar;585:740-749. doi: 10.1016/j.jcis.2020.10.054. Epub 2020 Oct 21.
A new-type nitrogen-rich carbon nitride material CN has been synthesized recently, in which the C:N ratio increases from 3:4 in g-CN to 3:5 due to the introduction of azo linkage (NN) connecting segments in two CN units. Herein, CN as a photocatalyst for CO reduction was investigated by density functional theory methods. The electronic and optical properties indicate that CN has a longer visible-light region with 2.0 eV of band gap in comparison with g-CN. The spatial distributions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) show that the π network of CN is extended by introducing -NN- linkage, which results in much higher photocatalytic efficiency than g-CN. The Gibbs free energies for possible CO reaction paths on CN were computed. The results show that CO can be reduced to CH with a low limiting potential of -0.54 V and to CHCHOH with a low limiting potential of -0.61 V, which all driven by solar energy. The present work is expected to provide useful guide for new-type nitrogen-rich CN as promising photocatalyst for CO reduction reaction (CORR).
最近合成了一种新型的富氮碳氮化物材料CN，由于在两个CN单元中引入了连接段的偶氮键（NN），其C:N比从g-CN中的3:4增加到3:5。在此，采用密度泛函理论方法研究了CN作为光催化剂用于CO还原的性能。电子和光学性质表明，与g-CN相比，CN具有更长的可见光区域，带隙为2.0 eV。最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）的空间分布表明，通过引入-NN-键，CN的π网络得以扩展，这导致其光催化效率比g-CN高得多。计算了CN上可能的CO反应路径的吉布斯自由能。结果表明，CO可以在低极限电位-0.54 V下还原为CH，并以低极限电位-0.61 V还原为CHCHOH，所有这些均由太阳能驱动。本工作有望为新型富氮CN作为有前景的CO还原反应（CORR）光催化剂提供有用的指导。
