Edge functionalization of terminal amino group in carbon nitride by in-situ C-N coupling for photoreforming of biomass into H2
Edge functionalization of terminal amino group in carbon nitride by in-situ C-N coupling for photoreforming of biomass into H2
复制标题
通过原位 C-N 偶联对氮化碳中的末端氨基进行边缘功能化，将生物质光重整为 H2
DOI：
10.1016/j.cej.2019.123792
复制
发表时间：
2020-03-01
影响因子：
15.1
通讯作者：
Wang, Fuxian
中科院分区：
文献类型：
--
作者：
Liu, Qiong;Wei, Liling;Wang, Fuxian
太阳能驱动的水裂解是一种很有前途的制氢方法，但为了加快反应速率，通常需要高成本的牺牲剂。生物质的光重整作为一种可持续的H-2产生的替代策略。氮化碳是一种很有前途的光催化剂，但其对可见光的吸收较差，影响了其光催化性能。在这里，我们首次报道了通过原位C-N耦合方法制备具有显著可见光吸收的边缘功能化氮化碳。通过使用N-乙酰乙醇胺（NA）作为添加剂与包括尿素、双氰胺和三聚氰胺的前体反应，乙醇基团通过取代末端氨基而接枝到七嗪环上。实验结果和密度泛函理论计算表明，乙醇基团的引入导致带隙中产生新的分立能级，从而显著增加了可见光吸收。本文中的乙醇基团用作电子供体，其将调节电子分布以形成内部电场来改善电荷分离。此外，乙醇基团的存在可以有利于生物质实体的吸收。在质子k还原Pt助催化剂的存在下，与原始CN相比，调谐CN显示出上级光重整性能。它允许在可见光驱动下将几种单糖转化为H-2，而不需要牺牲剂。
Solar-driven water splitting is a promising approach for H-2 generation, but in order to accelerate the reaction rate, high-cost sacrificial agents are usually required. Photoreforming of biomass serves as an alternative strategy for sustainable H-2 generation. Carbon nitride has recently emerged as a promising photocatalyst for the photorefoming reaction, however its performance is largely hindered by its poor visible light absorption. Here, we report, for the first time, the fabrication of an edge functionalized carbon nitride with remarkable visible light absorption via an in-situ C-N coupling method. By using N-acetylethanolamine (NA) as an additive to react with the precursors including urea, dicyandiamide, and melamine, the ethyl alcohol groups are grafted to the heptazine rings by replacing the terminal amino groups. Experimental results and DFT calculations reveal that the introduction of ethyl alcohol group leads to the generation of a new discrete energy level in the bandgap, resulting in significant increase in visible light absorption. The ethyl alcohol group herein serves as an electron donor, which would modulate the electron distribution to form an internal electric field to improve the charge separation. Moreover, the presence of ethyl alcohol group could favor the absorption of the biomass entity. The tuned CN shows superior photoreforming performance compared to the pristine CN in the presence of proton kreduction Pt cocatalysts. It allows for visible-light-driven conversion of several monosaccharides into H-2 without the need for sacrificial agents.