【作者】 张丽莹；

【导师】 王建明；

【作者基本信息】 浙江大学 ， 化学， 2014， 博士

【摘要】 本论文研究了新型光电储能体系Ni(OH)2/TiO2, NiOOH/TiO2, CoOOH/ZnO复合膜电极的制备方法,并测试了其性能。我们用阳极氧化法制备的Ti箔上的TiO2纳米管阵列在500WXe灯下(5mWcm-2),光电流是10-4A。在同样的条件下,用水热法在FTO导电玻璃上制备的TiO2纳米线阵列光电流是10-3A。虽然我们将Ti02纳米管在碱液中进行了电化学还原,一定程度上提高了其导电性,但是可惜的是并没有能提高其光活性。我们通过调整合成条件,将TiO2纳米线阵列的密度调整到最合适沉积Ni(OH)2的值。我们经过反复试验发现,以饱和食盐水和盐酸各7.5ml,钛酸四丁酯0.15ml溶液为前驱溶液,160℃水热15h可以得到密度最合适的TiO2纳米线阵列。以上述Ti02纳米线阵列为基体,我们用阴极电沉积的方法将Ni(OH)2沉积到基体上,制备了Ni(OH)2/TiO2复合膜电极。这种复合膜电极在光照下会由淡绿色变为黑色(Ni(OH)2被氧化为NiOOH),在光照过程中我们将复合膜电极与Pt对电极短接,可以有效地将TiO2中的光生电子由外电路转移到对电极上,从而降低光生电子空穴的复合,而且我们将复合膜电极和对电极分开放置,以盐桥连通,避免了副产物如H2O2等把NiOOH还原,经计算这种复合膜电极的IPCE可以达到6.8%,光照1h后在1μA的电流下放电可以放10000s以上,并可以进行反复光充电-放电。在光电储能体系中,光活性材料和储能材料的结合非常重要,而光沉积方法相比于传统的电沉积就方法,不仅可以使储能材料与光活性材料紧密结合,而且会使储能材料沉积在光活性位点上,提高光活性的利用率。我们正是基于这一思路,用光沉积的方法制备了NiOOH/TiO2复合膜电极,我们在光沉积液中加入不同量的SDS,一方面可以降低表面张力,另一方面SDS可以作为模板,使沉积的NiOOH片更厚,稳定性更好,SDS浓度在0-0.3wt%时光沉积的NiOOH都是交联的片状结构,当SDS浓度达到1.5wt%时,沉积的NiOOH是致密的薄膜。经过试验测试,我们发现SDS浓度是0.3wt%时,光沉积5h后得到的NiOOH/TiO2复合膜电极光电性能最好,IPCE可以达到8%。而且NiOOH/TiO2复合膜电极不仅可以用于放电,还能用于甲醛气体的探测与降解,可以在短时间内将甲醛浓度降解到人体可以接受的浓度,并且可以反复使用。我们用光沉积方法制备的CoOOH/ZnO复合膜电极用在葡萄糖电化学检测中,线性范围是1×10-5到2.4×10-4M(R2=0.996),响应灵敏度是40mA mM-1cm-2,比其他非酶类的电化学传感器的灵敏度都要高。更多还原

【Abstract】 In this dissertation, the Ni(OH)2/TiO2, NiOOH/TiO2, CoOOH/ZnO bilayer electrodes are studied as noble light energy conversion and storage systems. We discussed the fabricating methods and their properties.We prepared TiO2nanotube arrays on Ti foil by anodic oxidation method, and its photocurrent under illumination of500W Xe light (5mW cm-2) was10-4A. Under the same condition, the photocurrent of TiO2nanowire arrays grown on FTO conductive glass prepared by a simple hydrothermal method was10-3A. Although we treated the TiO2nanotube arrays in an alkaline solution to reduce it by electrochemical reduction, and this reduction had actually improved its conductivity, but unfortunately its photoactivity was not improved. So we took the TiO2nanowire arrays as the photoactive material.We adjusted the density of TiO2nanowire arrays to a value as optimal for the deposition of Ni(OH)2, by adjusting the synthesis conditions. After repeated experiments, we finally found that the best synthesis condition for TiO2nanowire arrays on FTO conductive glass was:the presoma was a solution containing the saturated salt water and hydrochloric acid7.5ml, respectively, and0.15ml butyl titanate, after hydrothermal reacting under160℃for15h, we could get the TiO2nanowires array with the most suitable density.Using the TiO2nanowire arrays above mentioned as the substrate, we deposited Ni(OH)2on it by cathodic electrodeposition to prepare Ni(OH)2/TiO2bilayer electrode. Under illumination of UV light, the plale green bilayer electrode would turn to black (Ni(OH)2was oxidized to NiOOH). In the illumination process, we made the bilayer electrode short circuited with the Pt counter electrode, then the photoexcited electrons could easily transport to the Pt electrode through the external circuit, and the recombination of photoexcited electrons and holes would be decreased; we also put the Pt electrode and the bilayer electrode in different containers and linked them by salt bridge, then the NiOOH would not be reduced by the by-product, such as H2O2etc., finally by calculation, the IPCE of the bilayer electrode reached to6.8%. The light energy stored in the bilayer could be discharged under1μA current for larger than10000s, and the light charge-discharge process could be repeated.In the light energy conversion and storage system, the contact between the photoactive material and energy storage system is very important. Compared with the traditional electrodeposition method, the material combined with the photoactive material by photodeposition can not only contact the photoactive material tightly, but also occupy the best photoactive sites, so the bilayer electrode can use the photoactivity to the best extent. Based on this idea, we prepared NiOOH/TiO2bilayer electrode by photodeposition. In the photodeposte solution we added different amounts of SDS. The SDS can not only reduce the surface tension of the solution but also act as template for the NiOOH-the NiOOH can be thicker and more stable. The NiOOH photodeposited from solution containing0-0.3wt%SDS was a nanoporous wet comprised of many nanoplates, but when the SDS reached to1.5wt%, the NiOOH became a dense film. We found that the bilayer photodeposited from solution containing0.3wt%SDS had the best property, and its IPCE could reach to8%. The light energy stored in NiOOH/TiO2could be used to discharge, and detect/degrade formaldehyde. With the bilayer electrode, the concentration of formaldehyde could be soon reduced to a value which the human body could withstand. For the NiOOH/Ti02bilayer electrode the light charge-discharge process could also be repeated.The CoOOH/ZnO bilayer electrode prepared by photodeposition could be used to detect glucose. The detection linear range was1*10-5to2.4*10-4M (R2=0.996), the response sensitivity is40mA mM-1cm-2, which was higher than the sensitivity of other non enzyme electrochemical sensors.更多还原