过渡金属化合物氮化钴和磷化镍用于光催化水分解制氢应用研究

发布时间：2018-02-08 19:43

本文关键词： 光催化制氢水分解助催化剂氮化钴磷化镍　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：能源短缺问题是目前人类面临的最重大的问题之一。通过光催化水分解完成太阳能到氢能的转化是解决当前能源问题的一条重要途径。在光催化水分解制氢的过程中,加入适当的助催化剂可以作为催化反应位点,促进催化剂中光生载流子的传输和分离,实现光催化剂反应活性的提升。贵金属是一类较高效的光催化水分解助催化剂材料,然而由于贵金属材料具有低储量、高成本等缺点,很大程度地制约了它们的大规模实际应用。故而探寻适用于光催化水分解制氢的非贵金属助催化剂极为重要。近些年来,人们发现第一周期过渡金属及其化合物在催化水分解方面表现出很好的性质。其中,金属镍单质和钴单质都能作为高效的催化水分解制氢催化剂,但是其易被氧化的缺点制约了它们的应用。本文主要研究了以下两种既能较好保持金属单质的催化活性,又具有较高稳定性的过渡金属化合物在光催化水分解制氢中的应用。1.氮化钴(Co3N)在光催化水分解制氢效果较好的半导体CdS纳米棒表面原位合成Co3N纳米颗粒,以Na2S和Na2SO3为牺牲剂,在可见光照射下测量其分解水制氢的效率。实验结果得其最大产氢速率可达到137.33μmolh-1 mg-1左右,产氢量子效率为14.9%左右。通过光致发光谱和光电流实验的分析,发现Co3N助催化剂可以有效地转移光生电子。2.磷化镍(Ni2P)石墨相氮化碳是非金属光催化剂,具有无毒、低成本等优点,但其因为光生载流子复合等问题,能量转换效率比较低下。我们通过使用一种简便的制备方法将其与Ni2P纳米颗粒复合,并测试该复合催化剂材料的可见光催化水分解制氢的性质。实验结果显示复合了 Ni2P纳米颗粒后,体系的产氢效率大大提升。光致发光谱表明Ni2P作为助催化剂可以有效地抑制光生载流子复合。
[Abstract]:The problem of energy shortage is one of the most important problems that mankind is facing at present. The conversion of solar energy to hydrogen energy by photocatalytic water decomposition is an important way to solve the current energy problem. In the process of photocatalytic water decomposition to produce hydrogen, The addition of appropriate cocatalyst can be used as the catalytic reaction site to promote the transport and separation of photogenerated carriers in the catalyst, and to enhance the activity of photocatalyst reaction. Precious metals are a kind of efficient photocatalytic catalyst materials for water decomposition. However, due to the disadvantages of low reserves and high cost of precious metal materials, their large-scale practical application is restricted to a great extent. Therefore, it is very important to explore non-noble metal cocatalysts suitable for photocatalytic water decomposition to produce hydrogen. It has been found that transition metals and their compounds exhibit good properties in catalytic water decomposition in the first cycle, in which both nickel and cobalt elements can be used as efficient catalysts for the production of hydrogen by catalytic water decomposition. However, their application is restricted by their easy oxidation. In this paper, the following two kinds of catalysts are studied, which can keep the catalytic activity of metallic elements well. Application of transition metal compounds with high stability in photocatalytic water decomposition to produce hydrogen. 1. Cobalt nitride Co _ 3N) synthesized in situ Co3N nanoparticles on the surface of semiconductor CdS nanorods with better photocatalytic water decomposition to produce hydrogen. Na2S and Na2SO3 were used as sacrificial agents. The experimental results show that the maximum hydrogen production rate can reach about 137.33 渭 molh-1 mg-1 and the quantum efficiency of hydrogen production is about 14.9%. The photoluminescence spectra and photocurrent experiments show that the maximum hydrogen production rate is about 137.33 渭 molh-1 mg-1, and the quantum efficiency of hydrogen production is about 14.9%. It is found that Co3N cocatalyst can effectively transfer photogenerated electrons. The graphite phase carbon nitride is a nonmetallic photocatalyst, which has the advantages of non-toxic and low cost, but it is due to the problems of photogenerated carrier recombination, etc. Energy conversion efficiency is relatively low. We use a simple preparation method to combine it with Ni2P nanoparticles. The properties of the composite catalyst material for hydrogen production by water decomposition under visible light were tested. The experimental results showed that the composite Ni2P nanoparticles were prepared. The photoemission spectra show that Ni2P as a co-catalyst can effectively inhibit photogenerated carrier recombination.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TQ116.2

【参考文献】