论文总字数：22566字

摘 要

基于g-C₃N₄和ZnO能带结构的差异构建的g-C₃N₄/ZnO复合催化剂材料，其光生电子可以从g-C₃N₄的导带转移到ZnO的导带上，而空穴可从ZnO的价带转移到g-C₃N₄的价带上，通过异质结结构可以有效促进电子–空穴的分离，从而显著提高催化剂的催化性能，因此g-C₃N₄/ZnO成为一种可靠的催化剂体系。然而，和当前其它的异质结结构一样，两种催化剂形成的异质结接触界面较小，从而在一定程度上限制了其催化性能。

本课题通过构建多孔g-C₃N₄/ZnO异质结的策略，有效提高了g-C₃N₄的比表面积，同时通过构建多区域异质结结构显著增加接触界面的面积，通过两者的协同效应进一步优化提高g-C₃N₄/ZnO体系的光催化效果，也为其它类似的结构的优化提供了借鉴方法。

本论文以双氰胺作为前驱物，以微纳尺寸的无机盐氧化镁为模板，焙烧制备多孔的g-C₃N₄中间体。以上述制备的多孔中间体为载体，以硝酸锌或者氯化锌为ZnO来源，采用浸渍法将多孔中间体浸渍于硝酸锌或者氯化锌的溶液中，干燥，随后二次热聚合，从而制备多孔g-C₃N₄/ZnO催化剂。

通过光电、XRD等表征手段来探究多孔结构及异质结的协同效应对催化性能的作用。表征结果显示通过构建多孔g-C₃N₄/ZnO异质结成功获得了多孔g-C₃N₄/ZnO催化剂，与纯g-C₃N₄催化剂相比光催化其性能得到了较大提升，其中掺杂比例为1:1 24mg的多孔g-C₃N₄/ZnO催化剂的催化效果为最优。

关键词：光催化剂 多孔g-C₃N₄ 浸渍法 协同效应

Construction of Porous g-C₃N₄/ZnO Heterojunction and Its Photocatalytic Properties

ABSTRACT

The g-C₃N₄/ZnO composite catalyst material based on the difference in g-C₃N₄ and ZnO band structure can transfer photogenerated electronics from the conduction band of g-C₃N₄ to the conduction band of ZnO, and the hole can be derived from the valence band of ZnO to the valence band of g-C₃N₄, the heterojunction structure could effectively promote the separation of electron-holes, thereby significantly improving the catalytic performance of the catalyst, so g-C₃N₄/ZnO becomes a reliable catalyst system. However, like other current heterojunction structures, the heterojunction contact interface formed by the two catalysts is small, which limits the catalytic performance to some extent.

By constructing a porous g-C₃N₄/ZnO heterojunction strategy, the specific surface area of g-C₃N₄ was effectively improved, and the area of the contact interface was significantly increased by constructing a multi-region heterojunction structure, which improves the photocatalytic effect of g-C₃N₄/ZnO system by the synergistic effect of the two，providing a reference for the optimization of other similar structures.

In this experiment, dicyandiamide was used as a precursor with a micro-nano size inorganic salt MgO as a template, and then a porous g-C₃N₄ intermediate was prepared by calcining. The porous intermediate prepared above is used as a carrier, choose zinc nitrate or zinc chloride as the source of ZnO, and the porous intermediate is immersed in a solution of zinc nitrate or zinc chloride by a dipping method, centrifugally dried, and then subjected to secondary thermal polymerization.,a porous g-C₃N₄/ZnO catalyst was prepared.

The effects of synergistic effects of porous structures and heterojunctions on catalytic performance were investigated by means of UV, XRD and other characterization methods. The characterization results show that the porous g-C₃N₄/ZnO catalyst was successfully obtained by constructing a porous g-C₃N₄/ZnO heterojunction. Compared with the pure g-C₃N₄catalyst, the photocatalytic performance was greatly improved, and the catalytic effect of porous g-C₃N₄/ZnO catalyst whose doping ratio is 1:1 24mg is optimal.

Key Words: photocatalyst; porous g-C₃N₄; impregnation method; synergistic effect

目 录

摘要......................................................I

ABSTRACT..............................................................................................II第一章 绪论.......................................................1

1.1 引言 1

1.2 太阳能 1

1.2.1 太阳能的优缺点 1

1.2.2 太阳能的转化 2

1.3 光催化原理 3

1.4 光催化剂简述 4

1.4.1 光催化剂分类 5

1.4.2 光催化剂应用 6

1.5 g-C₃N₄光催化剂的简述 7

1.6 改良g-C₃N₄光催化剂的研究进展 8

1.6.1 物理复合改性 8

1.6.2 化学掺杂改性 8

1.6.3 共聚改性 9

1.6.4 构建异质结结构 9

1.6.5 微观形貌调整 10

1.6.6 多孔结构 10

1.6.7 制成纳米薄膜 10

1.6.8 其他改性手段 11

1.7 本论文研究目的及内容 11

第二章 实验方法 12

2.1 实验原料 12

2.2 实验仪器 12

2.3 实验流程 12

2.3.1 多孔g-C₃N₄中间体的制备 12

2.3.2 多孔g-C₃N₄/ZnO催化剂的合成 13

2.4 实验表征方法 14

2.4.1 X射线衍射物相分析(XRD) 14

2.4.2 光电化学测试 14

2.5 可见光光度计光学性能分析 14

第三章 结果与讨论 16

3.1 XRD分析 16

3.2 光电化学性能测试分析 16

3.3光催化活性测试分析 16

第四章 结论与展望 18

4.1 实验结论 18

4.2 实验展望 18

参考文献 19

致谢 22

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