摘要本文采用表面具有介孔硅层的二氧化硅微球作为硬模板，制备了具有空心球结构的石墨相氮化碳（g-C3N4），并通过共沉淀和水热晶化手段在g-C3N4空心球表面沉积具有半导体性能的层状双金属氢氧化物（CoAl-LDH），得到了g-C3N4@CoAl-LDH空心球复合纳米半导体材料。g-C3N4空心球直径约300nm，具有较为均匀的粒径分布，球壳壁厚度在48nm左右。CoAl-LDH片层无规堆积在g-C3N4空心球表面，形成半导体复合异质结。同时，制备了g-C3N4/CoAl-LDH复合纳米片作为比较。光催化降解亚甲基蓝实验表明，由于g-C3N4@CoAl-LDH复合空心球材料表面LDH片层的密堆积，其光催化性能反而不如g-C3N4本体，而g-C3N4/CoAl-LDH复合纳米片则具有优于g-C3N4本体和g-C3N4@CoAl-LDH复合空心微球的光催化活性，具有更好的异质结界面结构。

同时，以葡萄糖作为模板，通过先钨酸钠水热反应，而后双氰胺聚合的方式，制备了WO3/g-C3N4复合空心微球。WO3/g-C3N4微球直径为1- 3 μm，壁厚300nm左右，壳层由WO3和g-C3N4纳米颗粒共同组成。对材料在可见光下光催化降解亚甲基蓝的实验表明，73519

WO3/g-C3N4复合微球形成了较好的异质结界面，其光催化性能对比单纯氧化钨粉体得到了较大提升。

毕业论文关键词：氮化碳，LDHs，光催化，降解

毕业设计说明书外文摘要

Title  Preparation and investigations on photocatalytic activity of g-C3N4/LDHs nanocomposite 

Abstract Hollow g-C3N4 nanosphere was prepared using nanostructured silica as the hard template, g-C3N4@CoAl-LDH was subsequently prepared via the deposition of CoAl-layered double hydroxide semiconductor by coprecipitation and hydrothermal crystallization process。 g-C3N4 nanospheres with diameter around 300nm had well-distributed particle size。 The thickness of the shell was about 48nm。 The nanosheets of CoAl-LDH randomly deposited on the surfaces of g-C3N4 for the formation of heterojunctions。 Meanwhile, g-C3N4/CoAl-LDH composite nanosheet was prepared for the comparison。 The photocatalytic activity measurements demonstrated that the hollow g-C3N4 nanosphere possessed lower photocatalytic degradation ability compare with the bulk g-C3N4, which may be resulted from the dense accumulations of CoAl-LDH nanosheets。 g-C3N4/CoAl-LDH composite nanosheet exhibited better photocatalytic activity than the g-C3N4 nanosphere and bulk g-C3N4 due to the more interfaces of heterojunctions。

WO3/g-C3N4 composite nanosphere was fabricated by the hydrothermal reaction of sodium tungstate precursor and subsequent dicyanodiamide polymerization with glucose as template。 The diameter of WO3/g-C3N4 nanosphere was ranged for 1 μm to 3 μm, and the thickness of shell was around 300 nm。 The shell was consist of WO3 and g-C3N4 nanoparticles。 WO3/g-C3N4 composite nanosphere displayed better photocatalytic activity than the powdery WO3, which ascribed to the efficient separation of photogenerated charge carriers。

Keywords:  carbon nitride; LDHs; photocatalysis; degradation

目   次

1 绪论 1

1。1 半导体光催化材料 1

1。1。1 半导体光催化机理 1

1。1。2 影响半导体光催化活性的因素 2

1。1。3 光催化技术的应用 3

1。1。4 目前光催化材料的局限性 4

1。2 g-C3N4光催化剂 4

1。2。1 g-C3N4光催化剂的发展历史 4

1。2。2 g-C3N4的结构及制备 5

1。2。3 特殊形貌的g-C3N4