过渡金属配合物修饰的光、电催化水氧化电极的研究

发布时间：2018-03-28 03:34

本文选题：水氧化　切入点：电解水　出处：《大连理工大学》2015年博士论文

【摘要】：水氧化反应能够为太阳能分解水制氢提供质子和电子,但水氧化涉及4个电子和4个质子的转移且需要很高的活化能,是实现人工光合作用的瓶颈。因此,发展廉价高效的水氧化催化剂及负载有催化剂的阳极和光阳极是实现太阳能转换和储存的关键。本文通过π-π堆积作用成功的将带芘吸附基团的高效水氧化催化剂Rul负载到导电性很好的MWCNTs电极上。得到Rul/MWCNTs/ITO阳极的氧化水过电位仅为280mV,在1.4Vvs NHE的电位下得到220pA/cm2稳定的催化电流密度。电解10h后的产氧TON为11000,TOF为0.39s-1。与羧酸官能团修饰的阳极相比,通过π-π堆积作用修饰的阳极不仅制备简便,而且对工作时电解液的pH值等条件没有特殊要求,为分子催化剂在阳极上的修饰开辟了一条新的途径。为进一步开发具有实际意义的光、电器件,本文选取廉价的立方烷Co水氧化分子催化剂,通过将Col催化剂嵌入Nafion聚合物覆盖的FTO导电玻璃和具有可见光吸收特性的α-Fe2O3半导体薄膜,制备了FTO/Nafion/Col复合阳极和FTO/Nafion/a-Fe2O3/Col光阳极。在电催化中,FTO/Nafion/Col复合阳极在中性磷酸缓冲溶液中1.4V下的催化电流密度为230μA/cm2,持续工作10h未见明显活性降低。在光催化中,在0.6V偏压和光照下,FTO/Nafion/α-Fe2O3/Col光阳极的催化光电流密度维持在350μA/cm2。这是首个不含贵金属的分子催化剂/无机半导体光阳极。本文还开发了基于钴氧化物的阳极。通过电沉积的方法简单而快速地得到了两个沉积在FTO电极表面具有电催化水氧化活性的非定型钴氧化物膜Co-W和Co-Mo。在Na2WO4和Na2MoO4溶液中,FTO/Co-W和FTO/Co-Mo阳极在1.4V电位下催化电流密度达到1.45mA/cm2和0.95mA/cm2。与己报道的Co-Pi催化剂相比,Co-W能在不含Co2+的电解液中稳定工作13h没有明显活性降低,这在实际应用方面具有重要意义。另外,本文以探索新型高效Fe水氧化分子催化剂为目的,对三齿、四齿、五齿配位；环状配体配位等不同类型配位环境的11个Fe配合物和9个原位生成的Fe配合物催化水氧化的活性进行研究。得到Fe3和Fe6两个新型水氧化Fe分子催化剂,其中Fe6的TON达到65,且具有优异的稳定性,为Fe分子催化剂修饰水氧化阳极奠定了基础。本文开发了高效廉价的水氧化分子催化剂,采用不同方法制备了多个水氧化催化剂修饰的阳极和首个非贵金属分子催化剂修饰的半导体光阳极,对构建高效光解水制氢体系有重要价值。
[Abstract]:Water oxidation can provide protons and electrons for solar energy to decompose water to produce hydrogen. However, water oxidation involves the transfer of 4 electrons and 4 protons and requires high activation energy, which is the bottleneck of artificial photosynthesis. The development of cheap and efficient water oxidation catalyst and supported anode and photoanode is the key to realize solar energy conversion and storage. In this paper, the highly efficient water oxidation catalyst (Rul) with pyrene adsorption group was successfully loaded on the MWCNTs electrode with good electrical conductivity by 蟺-蟺 piling. The oxidation water overpotential of Rul/MWCNTs/ITO anode was only 280 MV, and 220pA/cm2 was stable at the potential of 1.4Vvs NHE. After electrolysis for 10 h, the TON of oxygen production was 11000kT / F 0.39s-1.Compared with the anodes modified by carboxylic acid functional groups, the catalytic current density was determined. The anode modified by 蟺-蟺 stacking is not only easy to prepare, but also has no special requirement for pH value of electrolyte, which opens a new way for the modification of molecular catalyst on anode. In order to further develop light and electrical components of practical significance, a cheap Cuban-Co water oxidation molecular catalyst was selected in this paper. By embedding Col catalyst into FTO conductive glass covered by Nafion polymer and 伪 -Fe _ 2O _ 3 semiconductor film with visible light absorption property, FTO/Nafion/Col composite anode and FTO/Nafion/a-Fe2O3/Col photoanode were prepared. The catalytic current density of FTO / Nafion / Col composite anode was 230 渭 A / cm ~ 2 at 1.4 V in neutral phosphoric acid buffer solution in electrocatalysis. The photocurrent density of FTO / Nafion / 伪 -Fe _ 2O _ 3 / Col photoanode is maintained at 350 渭 A / cm ~ 2 路cm ~ (2). This is the first molecular catalyst / inorganic semiconductor photoanode without noble metal. The anode based on cobalt oxide was also developed. Two amorphous cobalt oxide films Co-W and Co-Mo-deposited on the surface of FTO electrode with electrocatalytic water oxidation activity were obtained by electrodeposition. In Na2WO4 and Na2MoO4. The catalytic current density of FTO / Co-W and FTO/Co-Mo anode reached 1.45mA/cm2 and 0.95mA / cm ~ 2 at 1.4V potential in solution. Compared with the reported Co-Pi catalyst, the co-W catalyst could work steadily in the electrolyte without Co2 for 13 h without obvious decrease in activity. This is of great significance in practical application. In addition, the aim of this paper is to explore a new high efficient catalyst for Fe water oxidation, and coordinate with three, four and five teeth. The catalytic activity of 11 Fe complexes and 9 in situ Fe complexes in different coordination environments, such as cyclic ligand coordination, for water oxidation was studied. Two novel Fe molecular catalysts, Fe3 and Fe6, were obtained. The TON of Fe6 reaches 65 and has excellent stability, which lays the foundation for Fe molecular catalyst to modify the water oxidation anode. In this paper, high efficient and cheap molecular catalysts for water oxidation have been developed. The anode modified by water oxidation catalyst and the semiconductor photoanode modified by the first non-noble metal molecular catalyst have been prepared by different methods. It is of great value for the construction of efficient photodissociation water hydrogen production system.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ116.2;O646

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