Hayat Asif, Khan Javid, Rahman Mati Ur, Mane Sunilkumar Baburao, Khan Wasim Ullah, Sohail Muhammad, Rahman Naveed Ur, Shaishta Naghma, Chi Zhenguo, Wu Mingmei
School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China.
School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China.
J Colloid Interface Sci. 2019 Jul 15;548:197-205. doi: 10.1016/j.jcis.2019.04.037. Epub 2019 Apr 13.
The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of polymeric carbon nitride (PCN), synthesized through chemical condensation of urea. The TMA-modified carbon nitride samples obtained were named as CNU-TMA and it was utilized for the photocatalytic reduction of carbon dioxide (CO) under visible light illumination. The induction of such electron donor-acceptor co-monomer (TMA) dominates the intramolecular structure of PCN by acting as a nucleophilic substitution substrate to facilitate the electron density in the π-electron conjugated system of PCN and thus elevate its photocatalytic activity. Also, this process of copolymerization with TMA, not only cause a significant diversion in the specific area, band gap, chemical composition, and structure of PCN but also promote efficient charge transport from ground state (HOMO) to the excited state (LUMO) of the PCN. For comparison, CNU samples modified with other co-monomers were prepared by the same method and were named as CNU-FDA (2,5-Furandicarboxylic acid), CNU-PDA (2,6-pyridinedicarboxylic acid), CNU-PTA (Phthalic acid). Similarly, co-monomer TMA was incorporated in other PCN precursors such as dyandicyanamide (DCDA), thiourea (SCN) and ammonium thiocyanate (NHSCN) and was named as CND-TMA, CNT-TMA, and CNA-TMA, respectively. Besides, the average weight ratio between urea and TMA was well tuned and also CNU-TMA gain a fabulous 16 fold-enhanced photocatalytic performance than blank CNU.
共轭共聚单体均苯三甲酸（TMA）被整合到通过尿素化学缩合合成的聚合氮化碳（PCN）的三嗪框架中。所获得的TMA改性氮化碳样品被命名为CNU-TMA，并将其用于可见光照射下二氧化碳（CO）的光催化还原。这种电子供体-受体共聚单体（TMA）的引入通过作为亲核取代底物来控制PCN的分子内结构，以促进PCN的π电子共轭体系中的电子密度，从而提高其光催化活性。此外，与TMA的共聚过程不仅导致PCN的比表面积、带隙、化学成分和结构发生显著变化，而且还促进了从基态（HOMO）到PCN激发态（LUMO）的有效电荷传输。为了进行比较，用相同方法制备了用其他共聚单体改性的CNU样品，并将其命名为CNU-FDA（2,5-呋喃二甲酸）、CNU-PDA（2,6-吡啶二甲酸）、CNU-PTA（邻苯二甲酸）。同样，共聚单体TMA被掺入其他PCN前体如双氰胺（DCDA）、硫脲（SCN）和硫氰酸铵（NHSCN）中，并分别命名为CND-TMA、CNT-TMA和CNA-TMA。此外，尿素与TMA之间的平均重量比得到了很好的调节，并且CNU-TMA的光催化性能比空白CNU提高了惊人的16倍。
