CdS基半导体光催化剂的光解水产氢活性和光生电荷特性的研究

发布时间：2018-06-26 18:25

  本文选题：硫化镉 + 非贵金属助催化剂　； 参考：《吉林大学》2015年博士论文

【摘要】：日益严重的能源危机，以及化石能源的消耗所造成的环境污染问题促使人类寻找新型清洁的能源来替代化石能源。氢能作为一种高效，绿色无污染的能源被认为是最有可能取代化石能源的新型能源之一。在众多产生氢气的方法中，利用取之不尽用之不竭的太阳光光催化产生氢气成为目前的研究重点。在光催化反应中起到将太阳能转化为氢能的中间媒介作用的是半导体光催化剂。而大部分的半导体光催化剂，例如TiO2， SrTiO3，只能利用紫外光。CdS是典型的II-VI族半导体光催化剂。CdS的导带电势要高于质子还原产生氢气的电势，可以用于光催化产氢。CdS的带隙为2.4eV，能够利用可见光产氢。但是CdS存的自身的一些缺陷限制了CdS在光催化产氢方面的应用。一方面CdS本身光生电荷复合的速率较快，光催化产生氢气的活性较低。因此为了提高CdS光催化产氢的活性，就需要在CdS的表面负载贵金属，，例如Pt，提高其光催化产氢活性。但是贵金属价格昂贵。CdS最为半导体光催化剂的另一个缺点是易发生光腐蚀。通常需要加入电子牺牲剂来消耗CdS的空穴，防止CdS所产生的空穴还原S2-，分解CdS。因此本论文的目标是寻找替代贵金属Pt的助催化剂（CuS，Co(OH)2）和构筑Z-型光催化体系，提高CdS电荷的分离效率和CdS光催化产氢的活性。 我们知道光催化反应是迁移到表面的光生电子在表面发生的光催化产氢反应，如果能够使更多的光生电子迁移到表面，那光催化产氢活性必定明显提高。因此对于表面光生电荷的传输特征的研究十分必要。本论文的另一个目标是利用表面光电压技术研究非贵金属助催化剂在表面所起的作用和对主体光催化半导体催化剂光生电荷行为的影响以及Z-型体系的构筑对光生电荷行为的影响。为构筑高效的，经济的光催化产氢体系提供理论基础。具体的工作如下： 1.采用简单的离子交换的方法合成了CuS/CdS， CuS/Zn0.8Cd0.2S光催化体系。场发射扫描电子显微镜（FESEM）,透射电子显微镜（TEM）和高分辨电子显微镜（HRTEM）的测试结果证明CuS助催化剂成功的负载到了CdS的表面。非贵金属助催化剂CuS提高了CdS的光催化产氢的活性。表面光电压（SPV）和表面光电流（SPC）的测试结果表明CuS在CdS的表面起到捕获光生电子的作用。为了进一步提高产氢活性，我们将CuS负载到固溶体Zn0.8Cd0.2S的表面，光解水产氢活性进一步提高。CuS助催化剂负载在固溶体的表面，使得SPV和TPV的光伏信号发生了反转。进一步证明了CuS在主体催化剂的表面起到捕获光生电子的作用。 2.采用简单的溶剂热和共沉淀的方法在CdS纳米棒的表面负载了Co(OH)2作为助催化剂构筑了Co(OH)2/CdS光催化体系。X-射线光电子能谱的测试结果表明负载到CdS表面的钴元素是以Co(OH)2的形式存在。 Co(OH)2作为助催化剂明显提高了CdS在全光谱以及可见光下光催化产氢的活性。表面光电压的测试结果表明Co(OH)2在CdS的表面起到捕获光生电子的作用，从而使得更多的光生电子累积到催化剂的表面。瞬态光电压的测试结果表明非贵金属助催化剂Co(OH)2的负载，提高了CdS光生电荷的分离效率，提高了CdS的光解水产氢的活性。测试15h后，Co(OH)2/CdS的光催化产氢活性并没有明显降低，说明Co(OH)2/CdS是相对稳定的光催化体系。 3.模拟自然界的光合作用构筑全固态的Z-型光催化体系CdS/WO3用于光催化产氢。单纯的WO3没有表现出光催化产氢活性，但是CdS负载到WO3的表面表现出明显的光催化产氢活性，并且明显高于单纯CdS的光催化产氢活性。然后我们用表面光电压技术对CdS/WO3光催化体系光生电荷特性进行了研究。表面光电压的测试结果表明，WO3中的光生电子与CdS中的光生空穴复合，从而使得更多的光生电子累计到CdS的表面，有利于CdS光解水产氢活性的提高。另一方面CdS光生电荷的分离效率提高了。
[Abstract]:The increasingly serious energy crisis, as well as the environmental pollution caused by the depletion of fossil fuels, has prompted human beings to search for new clean energy to replace fossil fuels. Hydrogen energy, as a highly efficient, green and pollution-free energy, is considered as one of the most likely alternative sources of fossil energy. The inexhaustible solar light catalyzed production of hydrogen has become the focus of current research. In the light of photocatalytic reaction, the intermediate medium of converting solar energy into hydrogen energy is a semiconductor photocatalyst. Most of the semiconductor photocatalysts, such as TiO2, SrTiO3, can only use ultraviolet.CdS as the typical II-VI semiconductors The conduction band of the photocatalyst.CdS is higher than the potential of the proton reduction to produce hydrogen. The band gap of the photocatalytic hydrogen producing.CdS is 2.4eV and can be used to produce hydrogen with visible light. However, some of the defects of the CdS deposit limit the application of CdS in the photocatalytic hydrogen production. On the one hand, the rate of CdS itself is faster, and the photocatalytic production is produced. The activity of hydrogen is low, so in order to improve the activity of CdS photocatalytic hydrogen production, it is necessary to load precious metals on the surface of CdS, such as Pt, to improve its photocatalytic activity of hydrogen production. However, the other disadvantage of the expensive metal.CdS is that the other disadvantage of the semiconductor photocatalyst is easy to produce light corrosion. The electronic sacrificial agent is usually required to consume CdS. Holes, which prevent the holes produced by CdS to restore the S2-, decompose the CdS., so the aim of this paper is to find the co catalyst (CuS, Co (OH) 2) instead of the noble metal Pt, and to construct the Z- type photocatalytic system to improve the separation efficiency of CdS charge and the activity of the CdS photocatalytic hydrogen production.
We know that photocatalytic reaction is a photocatalytic hydrogen producing reaction on the surface of photogenerated electrons that migrate to the surface. If more photoelectrons are transferred to the surface, the photocatalytic activity of hydrogen production must be improved obviously. Therefore, it is necessary to study the characteristics of the transmission of surface photogenerated charge. The surface photovoltage technique studies the effect of non precious metal cocatalysts on the surface and the effect on the photoinduced charge behavior of the main photocatalyst and the structure of the Z- type system on the photoinduced charge behavior. It provides a theoretical basis for the construction of efficient and economical photocatalytic hydrogen production system. The specific work is as follows:
1. a simple ion exchange method was used to synthesize the CuS/CdS, CuS/Zn0.8Cd0.2S photocatalytic system. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution electron microscope (HRTEM) test results proved that the CuS Co catalyst was successfully loaded onto the surface of CdS. The non noble metal co catalyst CuS increased CdS. The test results of photocatalytic hydrogen production. The test results of surface photovoltage (SPV) and surface photocurrent (SPC) show that CuS plays a role in the capture of photoelectron on the surface of CdS. In order to further improve the activity of hydrogen production, we load the CuS to the surface of the solid solution Zn0.8Cd0.2S, and the photodissociation of aquatic hydrogen activity further improves the.CuS cocatalyst load in the solid solution. The surface makes the photovoltaic signal of SPV and TPV reverse, further proving that CuS plays the role of capturing photoelectrons on the surface of the main catalyst.
2. a simple solvent heat and coprecipitation method was used to load the Co (OH) 2 on the surface of the CdS nanorods as a co catalyst to construct the.X- ray photoelectron spectroscopy of the Co (OH) 2/CdS photocatalyst. The results showed that the cobalt element loaded to the CdS surface was in the form of Co (OH) 2. Co (OH) 2 was obviously improved in all light as a co catalyst. The test results of the surface photovoltage show that Co (OH) 2 plays a role in the capture of photogenerated electrons on the surface of CdS, thus making more photoelectrons accumulated on the surface of the catalyst. The transient photovoltage test results show that the load of Co (OH) 2 of the non noble metal co catalyst improves the CdS photoelectricity. The separation efficiency of charge increases the activity of CdS's photolysis of aquatic hydrogen. After testing 15h, the activity of photocatalytic hydrogen production of Co (OH) 2/CdS has not been significantly reduced, indicating that Co (OH) 2/CdS is a relatively stable photocatalytic system.
3. simulates the photosynthesis of the nature to construct the solid state Z- photocatalytic system CdS/WO3 for the photocatalytic hydrogen production. The pure WO3 does not show the photocatalytic hydrogen production activity, but the CdS load to WO3 shows obvious photocatalytic hydrogen production activity, and is obviously higher than the photocatalytic hydrogen production activity of pure CdS. Then we use surface optoelectronics. The characteristics of the photoinduced charge in the CdS/WO3 photocatalytic system were studied by pressure technique. The test results of surface photovoltage showed that the photogenerated electrons in the WO3 were combined with the photogenerated holes in the CdS, thus making more photoelectrons accumulated on the surface of the CdS, which was beneficial to the increase of the activity of the aquatic hydrogen in the photolysis of CdS. On the other hand, the separation efficiency of the CdS light generated charge was on the other hand. It's improved.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O643.36;TQ116.2

【相似文献】

相关期刊论文 前10条

1 林明,任南琪,王爱杰,马放;高效产氢发酵细菌在不同气相条件下产氢[J];中国沼气;2002年02期

2 林明,任南琪,王爱杰,张颖,王相晶,马放;几种金属离子对高效产氢细菌产氢能力的促进作用[J];哈尔滨工业大学学报;2003年02期

3 张志民;金美芳;虞星炬;张卫;;固定化亚心形扁藻光解水产氢研究[J];化工学报;2004年S1期

4 李永峰,任南琪,杨传平,胡立杰,郑国香;一株高效产氢产酸细菌的鉴定与产氢特性[J];中国环境科学;2005年02期

5 郑先君,陈志军,魏丽芳,危俊婷,谢冰;不同底物种类对厌氧发酵产氢的影响[J];河南化工;2005年07期

6 贾立娜,张栩,谭天伟,施定基;谷氨酸废液培养莱茵衣藻的产氢研究[J];生物加工过程;2005年01期

7 刘飞;方柏山;;微生物产氢机理的研究进展[J];工业微生物;2007年03期

8 陆玮;;产氢—产酸发酵微生物群落生态学探究[J];科技经济市场;2007年04期

9 张全国;师玉忠;张军合;杨群发;周磊;;太阳光谱对光合细菌生长及产氢特性的影响研究[J];太阳能学报;2007年10期

10 张全国;荆艳艳;周雪花;李鹏鹏;尤希凤;;吸附法固定光合细菌技术产氢能力的研究[J];农业工程学报;2008年09期

相关会议论文 前10条

1 吴薛明;申宁;何冰芳;;活性污泥厌氧发酵产氢能力的研究[A];第一届全国化学工程与生物化工年会论文摘要集(下)[C];2004年

2 康铸慧;王磊;周琪;;不产氧光合细菌Rhodobacter Sphaeroides产氢影响因子的实验研究[A];2005中国可持续发展论坛——中国可持续发展研究会2005年学术年会论文集（下册）[C];2005年

3 贾立娜;张栩;谭天伟;;葡萄糖对莱茵衣藻的产氢影响研究[A];2005年中国生物质能技术与可持续发展研讨会论文集[C];2005年

4 郭祯;陈兆安;虞星炬;金美芳;刘远;张卫;;不同培养基培养的亚心形扁藻直接光照产氢[A];第七届全国氢能学术会议论文集[C];2006年

5 刘爽;;不同原料厌氧暗发酵产氢特性研究[A];中国农业工程学会2011年学术年会（CSAE 2011）论文摘要集[C];2011年

6 李建政;任南琪;秦智;;有机废水产酸发酵典型类型的产氢能力[A];第七届全国氢能学术会议论文集[C];2006年

7 王占青;刘U

本文编号：2070997