Synthesis of an iso-type graphitic carbon nitride heterojunction derived from oxamide and urea in molten salt for high-performance visible-light driven photocatalysis
Synthesis of an iso-type graphitic carbon nitride heterojunction derived from oxamide and urea in molten salt for high-performance visible-light driven photocatalysis
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由草酰胺和尿素在熔盐中合成同型石墨氮化碳异质结，用于高性能可见光驱动光催化
DOI：
10.1039/d2nj00741j
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发表时间：
2022
影响因子：
3.3
通讯作者：
Kaneco Satoshi
中科院分区：
文献类型：
--
作者：
Ashraful Islam Molla Md.;Katsumata Hideyuki;Furukawa Mai;Tateishi Ikki;Kaneco Satoshi
本研究的重点是合成具有氰基和不对称平面七嗪/三嗪基同型结构的三次修饰g-C3N4（氮化碳；CN）的简单方法。尿素在熔融盐（KCl + LiCl）和草酰胺存在下的热聚合很容易产生一种有效的光催化剂，具有对CN框架（以下简称MOCN）的期望修饰。采用各种表征技术来评价合成的MOCN的性能。与原始CN相比，MOCN对双酚A （BPA）的降解活性显著提高。g-C3N4的三重化学结构修饰使其降解双酚a的速率常数比使用原始CN时提高11.6倍。MOCN光催化性能的提高可归因于其比表面积的增加、能带结构/带隙的改变、子隙的形成、高效的电荷分离/转移以及较低的电子-空穴（e−/h+）复合率。氰基是MOCN的强吸e -基团，促进了光生e - /h+对在其表面的快速分离和转移。MOCN在多次光催化反应中表现出较高的稳定性，并成功地将BPA矿化为CO2和H2O。该研究补充了目前对g-C3N4原位改性的认识，并表明MOCN是一种非常有效、可见光敏感、稳定、可重复使用的光催化剂，在环境净化方面具有潜在的应用前景。
This research focuses on a straightforward method for synthesising thrice-modified g-C3N4 (carbon nitride; CN) with cyano groups and an asymmetric planar heptazine/triazine-based iso-type structure. The thermal polymerisation of urea in the presence of molten salt (KCl + LiCl) and oxamide easily produced an effective photocatalyst featuring the desired modifications to the CN framework (hereafter referred to as MOCN). Various characterisation techniques were performed to evaluate the properties of the synthesised MOCN. Compared with pristine CN, MOCN exhibited considerably greater activity toward bisphenol A (BPA) degradation. The triple chemical structural modification of g-C3N4 resulted in an 11.6-fold increase in rate constant for BPA degradation compared with that obtained when pristine CN was used. The improved photocatalytic performance of MOCN could be attributed to its enhanced specific surface area, changes in its energy band structure/bandgap, sub-gap formation, efficient charge separation/transfer, and low electron–hole (e−/h+) recombination rate. The cyano groups, which are strong e−-withdrawing groups, of MOCN promoted the rapid separation and transport of photogenerated e−/h+ pairs on its surface. MOCN exhibited high stability during repeated photocatalytic reactions and successfully mineralised BPA to CO2 and H2O. This research supplements the current understanding of the in situ modification of g-C3N4 and presents MOCN as a remarkably effective, visible-light sensitive, stable, and reusable photocatalyst with potential use in environmental purification.