本文選題：氧電極 + 氧還原反應(yīng)　； 參考：《蘭州大學(xué)》2017年博士論文

【摘要】：氧電極包括兩個(gè)重要的反應(yīng),即氧析出反應(yīng)(OER)和氧還原反應(yīng)(ORR),其效率的高低決定著許多電化學(xué)能量轉(zhuǎn)換系統(tǒng)(如燃料電池、金屬空氣電池和裂解水系統(tǒng))的性能。然而,這兩個(gè)反應(yīng)的動(dòng)力學(xué)緩慢,且需依賴于貴金屬催化劑(如RuO_2、IrO_2、Pt),因而極大地制約了這些技術(shù)的商業(yè)化發(fā)展。近年來(lái),研究者們將氧電極催化劑的目光越來(lái)越多的聚集在各種以碳材料為基底的非貴金屬催化劑上。本論文致力于發(fā)展高活性的鈷基碳納米管材料并將其作為氧電極催化劑,制備了幾種基于碳納米管的鈷基復(fù)合納米材料,并系統(tǒng)地研究了其結(jié)構(gòu)特征和電化學(xué)性能。主要研究如下:1.超聲輔助法快速制備CNTs-Au@Co_3O_4管狀催化劑作為一種優(yōu)異的電極材料用于陽(yáng)極析氧通過(guò)超聲法合成了均勻負(fù)載的碳納米管/金屬/過(guò)渡金屬氧化物(CNTsAu@Co_3O_4)的管狀雜化材料,該制備過(guò)程簡(jiǎn)單、溫和、快速,且不需要加任何表面活性劑或進(jìn)行熱處理。在堿性介質(zhì)中,CNTs-Au/Co_3O_4具有良好的析氧活性,起始電位為1.50 V _(vs).RHE,達(dá)到電流密度為10 mA cm~(-2)時(shí)的過(guò)電位為350 mV,并且可以保持至少25小時(shí)。還研究了不同電負(fù)性的金屬納米顆粒對(duì)析氧電催化活性的影響。研究結(jié)果表明,電負(fù)性最高的Au納米顆�？梢源龠M(jìn)活性中心Co~(IV)的形成。此外,本論文提出OER在CNTs-Au/Co_3O_4表面反應(yīng)的機(jī)理。2.超薄的Co1_(-y)Fe_yO_x納米片同軸包裹在CNTs上用于催化水氧化反應(yīng)通過(guò)一步法制備了同軸包裹在CNTs上的管狀鐵族二元金屬超薄納米片雜化材料(Co1_(-y)Fe_yO_x/CNTs),深入討論了催化劑的設(shè)計(jì)、制備及結(jié)構(gòu),全面分析了組分、結(jié)構(gòu)、導(dǎo)電基底等各因素對(duì)OER活性的影響。研究表明:(1)同軸、超薄的納米片更利于暴露活性位點(diǎn)、縮短擴(kuò)散途徑、提高接觸面積;(2)Fe的摻雜會(huì)產(chǎn)生部分電荷轉(zhuǎn)移活化(PCTA)作用,繼而提高CoⅢ/CoⅣ的氧化能力,加快OER速率。在堿性溶液中,Co_(0.8)Fe_(0.2)O_x/CNTs25 wt%雜化材料表現(xiàn)出非常優(yōu)異的OER催化活性,起始電位為1.45 V vs.RHE,塔菲爾斜率為49 mV dec-1,達(dá)到電流密度為10 mA cm-2時(shí)的過(guò)電位僅為280 mV,并且可以保持至少14小時(shí)。該催化性能優(yōu)于商業(yè)的RuO_2和許多高活性的貴金屬及過(guò)渡金屬催化劑。3.鈷的有機(jī)金屬框架結(jié)構(gòu)和碳納米管的自組裝雜化材料:一種高效、可抗碳腐蝕的雙功能催化劑用于析氧反應(yīng)和氧還原反應(yīng)金屬有機(jī)框架結(jié)構(gòu)是由有機(jī)配體和金屬離子或團(tuán)簇通過(guò)配位鍵自組裝形成的具有分子內(nèi)孔隙的有機(jī)-無(wú)機(jī)雜化材料,具有豐富的骨架結(jié)構(gòu)、良好的孔結(jié)構(gòu)、高的比表面積和大的孔徑。本論文選擇了一種含鈷的沸石咪唑框架結(jié)構(gòu)(簡(jiǎn)稱Co-MOF),并用溫和的自組裝法合成一種兼?zhèn)涓呋钚院蛷?qiáng)穩(wěn)定性的雙功能催化劑Co-MOF@CNTs用于OER和ORR反應(yīng)。其中,CNTs與Co-MOF相互貫穿與支撐,不僅有效地提高了材料的導(dǎo)電性而且維持了材料在水氧化過(guò)程中的高氧化電位下不發(fā)生碳腐蝕。這種分層結(jié)構(gòu)的雜化材料表現(xiàn)出與RuO_2和20 wt%Pt/C催化效果相當(dāng)?shù)腛ER和ORR活性和更加優(yōu)異的穩(wěn)定性。
[Abstract]:Oxygen electrodes include two important reactions, namely, oxygen precipitation reaction (OER) and oxygen reduction reaction (ORR), and their efficiency determines the performance of many electrochemical energy conversion systems (such as fuel cells, metal air batteries and cracking water systems). However, the kinetics of these two reactions are slow and need to be dependent on the noble metal catalysts (such as RuO_2, IrO_2, P). T), thus greatly restricts the commercialization of these technologies. In recent years, researchers have focused more and more attention on the oxygen electrode catalysts on various non precious metal catalysts based on carbon materials. This paper is devoted to the development of highly active cobalt based carbon nanotube materials and the preparation of several kinds of oxygen electrode catalysts. Carbon nanotube based cobalt based composite nanomaterials have been studied systematically and their electrochemical properties are systematically studied. The main research is as follows: 1. ultrasonic assisted preparation of CNTs-Au@Co_3O_4 tubular catalyst as an excellent electrode material is used as an excellent electrode material for the synthesis of uniform loaded carbon nanotubes / metal / transition gold by ultrasonic method. The tubular hybrid material of the oxide (CNTsAu@Co_3O_4) is simple, mild and fast, without any surface active agent or heat treatment. In the alkaline medium, CNTs-Au/Co_3O_4 has good oxygen evolution activity and the starting potential is 1.50 V vs.RHE, and the overpotential at the current density of 10 mA cm~ (-2) is 350 mV, and The effect of different electronegativity metal nanoparticles on the electrocatalytic activity of oxygen evolution was also studied. The results showed that the highest electronegativity Au nanoparticles could promote the formation of active center Co~ (IV). In addition, this paper proposed that the mechanism of OER on CNTs-Au/Co_3O_4 surface reaction is.2. ultra-thin Co1_ (-y) Fe_yO_x Nana. A tube shaped iron group of two yuan metal super thin nano chip hybrid material (Co1_ (-y) Fe_yO_x/CNTs) coaxially wrapped in CNTs was prepared by one step method for the catalytic water oxidation of rice on CNTs. The design, preparation and structure of the catalyst were discussed in depth. The effects of components, structure and conductive substrate on the activity of OER were analyzed. Research shows that (1) (1) coaxial, ultra-thin nanoscale is more conducive to exposure to active sites, shorten the diffusion pathway and increase contact area; (2) the doping of Fe will produce partial charge transfer activation (PCTA), and then increase the oxidation capacity of Co III /Co IV and accelerate the OER rate. In alkaline solution, Co_ (0.8) Fe_ (0.2) O_x/CNTs25 wt% hybrid material shows non The often excellent OER catalytic activity, the starting potential of 1.45 V vs.RHE, and the Tafel slope of 49 mV dec-1, is only 280 mV when the current density is 10 mA cm-2, and can remain at least 14 hours. The catalytic performance is superior to the commercial RuO_2 and many highly active precious metals and the transition metal catalysts for the organometallic framework of.3. cobalt. A self assembled hybrid material for carbon nanotubes: a highly efficient, carbon resistant, bifunctional catalyst used in oxygen evolution and oxygen reduction. The organic frame structure is an organic inorganic hybrid material composed of organic ligands and metal ions or clusters formed by self assembly through the coordination bonds. It has a rich skeleton. The structure, good pore structure, high specific surface area and large aperture. In this paper, a cobalt containing zeolite imidazole frame structure (Co-MOF) was selected, and a dual functional catalyst, Co-MOF@CNTs, which had both high activity and strong stability, was synthesized by a mild self-assembly method for the reaction of OER and ORR. Among them, CNTs and Co-MOF were interpenetrated and supported, It not only effectively improves the conductivity of the material but also maintains the material without carbon corrosion under the high oxidation potential in the process of water oxidation. This layered hybrid material shows the activity of OER and ORR, which is equivalent to the catalytic effect of RuO_2 and 20 wt%Pt/C, and the more excellent stability.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：O646;O643.36

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;Advanced technology for functionalization of carbon nanotubes[J];Progress in Natural Science;2009年07期

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本文編號(hào)：2070829