A quadruple-strategy of modification on carbon nitride boosts oxygen reduction for high performance photocatalytic hydrogen peroxide production.
A quadruple-strategy of modification on carbon nitride boosts oxygen reduction for high performance photocatalytic hydrogen peroxide production.
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DOI：
10.1016/j.jcis.2023.11.081
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发表时间：
2023-11
影响因子：
9.9
通讯作者：
Sha Wen;Lin Zi;Ying Liu;Bo Wang;Kexin Zhang;Senpei Tang;You-ji Li
中科院分区：
文献类型：
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作者：
Sha Wen;Lin Zi;Ying Liu;Bo Wang;Kexin Zhang;Senpei Tang;You-ji Li
本文报道了一种材料设计的四重策略，将形貌控制、基团修饰、缺陷工程和碱金属掺杂同时应用于催化剂的设计，成功构建了具有优良光生载流子分离性能和结构稳定性的不规则氮化碳团簇（pMNK-CN）。pMNK-CN是一种不规则的花簇状形态，表面具有纳米片结构，预聚物在金属盐微孔中的再聚合过程使其具有开放的孔结构。借助必要的表征，证实了由于金属盐在高温下的蚀刻，主链中的七嗪单元发生了部分分解，降低了整体聚合并引入了氰基和氮空位。同时，钾离子嵌入晶格可以诱导有序结构的生长，从而提高短程有序度。pMNK-CN在纯水中的过氧化氢生产效率为240.0 μmol·g−1·h− 1，是块状氮化碳的31倍。在异丙醇存在下，pMNK-CN在380和420 nm波段的表观量子效率分别为17.5%和14.8%。利用第一性原理研究了各种改性策略对氮化碳电子结构的影响，结果表明，多种改性策略协同提高了氮化碳的光吸收、光生电荷分离效率，降低了反应能垒，从而大大提高了氮化碳的氧还原为过氧化氢的性能.
This paper reports a quadruple-strategy for material design, simultaneously applying morphology control, group modification, defect engineering and alkali metal doping to the design of catalysts, and successfully constructing irregular clusters of carbon nitride (pMNK-CN) with excellent photogenerated carrier separation performance and structural stability. The pMNK-CN is an irregular flower cluster-like morphology with a nanosheet structure on the surface, and the repolymerization process of the prepolymer in the microvoid of the metal salt gives it an open pore structure. With the help of essential characterization, it was confirmed that the heptazine unit in the backbone underwent partial decomposition due to the etching of metal salts at high temperatures, reducing the overall polymerization and introducing cyano and nitrogen vacancies. Meanwhile, the potassium ion embedded in the lattice can induce the growth of ordered structures and thus improve the short-range order. The pMNK-CN possesses a hydrogen peroxide production efficiency of 240.0 μmol·g−1·h−1in pure water, which is 31 times higher than that of bulk carbon nitride. And the apparent quantum efficiencies of pMNK-CN in the 380 and 420 nm bands are 17.5 % and 14.8 % in the presence of isopropanol. The effects of each modification strategies on the electronic structure of carbon nitride were investigated using First-Principles, and it was demonstrated that the multiple modification strategies synergistically enhanced the optical absorption, photogenerated charge separation efficiency, and lowered the reaction energy barrier, thus greatly contributing to the oxygen reduction to hydrogen peroxide performance.