College of Chemistry, Fuzhou University, Fuzhou 350002, China.
Key Laboratory of Functional Inorganic Material Chemistry, School of Chemistry and Materials Science, Heilongjiang University, Harbin 158308, China.
Molecules. 2019 May 8;24(9):1779. doi: 10.3390/molecules24091779.
This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO reduction to CO and H under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor-acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid-base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H from CO by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.
这项工作采用独特的纳米结构共聚策略,将各种共轭给体-受体(DA)共聚单体(如 2,6-二氨基嘌呤(DP))引入聚合物碳氮化物(PCN)骨架结构中,并研究了其在可见光照射下光催化 CO 还原为 CO 和 H 的光催化活性性能。使用不同的表征方法成功分析了合成的样品,以解释它们的电子和光学性质、晶体相、微结构及其形态,这些性质由于 PCN 和 DP 共聚单体之间的相互作用而影响性能。基于密度泛函理论(DFT)计算结果,广泛评估了纯 PCN 和 CNU-DP 三聚体(解释为在两个不同位置掺入共聚单体),它们表现出显著的结构优化,而没有包含任何对称约束(未修饰的尿素衍生样品,命名为 CNU),并且还操纵了它们的光学和电子性质,以控制各自最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)的占据。此外,供体-受体 2,6-二氨基嘌呤共聚单体与 PCN 的共聚显著影响了 PCN 的化学亲和力、极性和酸碱功能,与母体 CNU 相比,将 CO 光催化转化为 CO 和 H 的光催化活性显著提高了 15.02 倍,同时还提高了选择性。