From urea to high-efficiency photocatalyst: The impact of confined-degree and silica support on structure engineering of carbon nitride

IF 5.5 3区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of the Taiwan Institute of Chemical Engineers Pub Date : 2024-11-28 DOI:10.1016/j.jtice.2024.105849

Zhaoli Yan , Tiantian Li , Li Wang , Yongsheng Yu , Xi He , Peng Liu , Qiangshan Jing

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引用次数: 0

Abstract

Background

The synthesis of g-C₃N₄ (CN) through confined pyrolysis of urea is a widely employed method. However, the impact of confined-degree on the nano- and molecular-structure of CN has been scarcely addressed.

Methods

We investigated this influence by varying the confined-degree of the covered crucibles used for urea pyrolysis. Additionally, a silica nanosheet (SiNS) support was incorporated to achieve high dispersion and easy use.

Significant findings

With increasing confined-degree, the crystallinity and porosity of the synthesized CN nanosheets initially decreased and then increased, whereas the size and dispersion exhibited an opposite tendency. The introduction of SiNS primarily enhanced the yield (excepting CN/SiNS-1), reduced the size (excepting CN/SiNS-4), and improved the dispersion of the supported CN nanosheets. Furthermore, larger CN nanosheets with greater dispersion enhanced the separation efficiency of photoinduced carriers, whereas smaller nanosheets with higher crystallinity displayed a more negative conduction band minimum potential (E_CBM), offering more reactive oxygen species. Therefore, the optimal CN/SiNS-4 composite exhibited significant photocatalytic activity for degrading Rhodamine B in 25 min, with an apparent rate constant of 0.189 min⁻¹, owing to the nanostructure dependent photoreactivity of the well-dispersed and small-sized CN nanosheets, and the strong adsorption capacity of SiNS and urea-derived CN.

Abstract Image

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从尿素到高效光催化剂：封闭度和二氧化硅支撑对氮化碳结构工程的影响

背景通过密闭热解尿素合成 g-C3N4 (CN) 是一种广泛采用的方法。我们通过改变用于尿素热解的有盖坩埚的密闭度来研究其影响。重要发现随着密闭度的增加，合成的氯化萘纳米片的结晶度和孔隙率先减小后增大，而尺寸和分散度则呈现出相反的趋势。SiNS 的引入主要提高了所支持的 CN 纳米片的产率（CN/SiNS-1 除外）、减小了尺寸（CN/SiNS-4 除外）并改善了分散性。此外，具有更大分散性的较大 CN 纳米片提高了光诱导载流子的分离效率，而结晶度较高的较小纳米片则显示出更负的导带最低电位（ECBM），提供了更多的活性氧。因此，最佳的 CN/SiNS-4 复合材料在 25 分钟内降解罗丹明 B 的表观速率常数为 0.189 min-1，表现出显著的光催化活性，这是由于分散性好、尺寸小的 CN 纳米片具有与纳米结构相关的光活性，以及 SiNS 和尿素衍生 CN 具有很强的吸附能力。

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来源期刊

Journal of the Taiwan Institute of Chemical Engineers 工程技术-工程：化工

CiteScore

9.10

自引率

14.00%

发文量

362

审稿时长

35 days

期刊介绍： Journal of the Taiwan Institute of Chemical Engineers (formerly known as Journal of the Chinese Institute of Chemical Engineers) publishes original works, from fundamental principles to practical applications, in the broad field of chemical engineering with special focus on three aspects: Chemical and Biomolecular Science and Technology, Energy and Environmental Science and Technology, and Materials Science and Technology. Authors should choose for their manuscript an appropriate aspect section and a few related classifications when submitting to the journal online.