鉑基燃料電池催化劑的可控合成與電催化性能的研究
發(fā)布時(shí)間：2018-09-18 09:59
【摘要】：使用量日益增長(zhǎng)的化石能源在提高我們生活質(zhì)量的同時(shí),也帶來了嚴(yán)重的環(huán)境污染,因此開發(fā)一種綠色能源是緩解目前環(huán)境危機(jī)的唯一途徑。質(zhì)子交換燃料電池作為一種新型能源,運(yùn)行過程中不排放污染物,是理想的化石能源的替代品。但質(zhì)子交換燃料電池的高效運(yùn)行,依賴于價(jià)格昂貴的鉑和基于鉑的貴金屬催化劑,這嚴(yán)重阻礙了質(zhì)子交換燃料電池的大規(guī)模應(yīng)用,因此,質(zhì)子交換燃料電池研究中的主要內(nèi)容就是提高鉑的催化活性。大量研究證實(shí),鉑的催化性能嚴(yán)重依賴于表面結(jié)構(gòu)。特別是高指數(shù)晶面,因其表面原子配位數(shù)低,而具有更高的催化活性。本文主要是在水-乙二醇這一簡(jiǎn)單體系中通過調(diào)節(jié)合成參數(shù),開發(fā)出一系列具有高催化活性的燃料電池催化劑。本文主要在以下幾個(gè)方面開展了研究： 1、鉑多足分支納米結(jié)構(gòu)的可控合成與電催化性能的研究：納米晶體的表面參數(shù)(特別是比表面積、表面原子分布情況)是影響納米催化劑性能的重要因素,分枝結(jié)構(gòu)的結(jié)構(gòu)特征使其具有很好的催化性能,然而在實(shí)際合成中卻很難實(shí)現(xiàn)分枝數(shù)目的可控性。在這個(gè)工作中,通過調(diào)控合成過程中加入的HCl量,實(shí)現(xiàn)了不同分枝數(shù)目的Pt納米結(jié)構(gòu)的可控合成。在這個(gè)反應(yīng)中,HCl的氧化刻蝕在納米晶的合成中起到三個(gè)方面的調(diào)控作用：(1)調(diào)控納米晶和晶種的結(jié)晶度；(2)調(diào)控{111},{100}晶面的數(shù)量；(3)調(diào)控新生供給原子的濃度。因此,通過調(diào)控HCl刻蝕劑加入量的簡(jiǎn)單方法,可以實(shí)現(xiàn)三足、四足、六足和八足的Pt納米分支結(jié)構(gòu)的可控合成。這種可控合成的方法揭示了結(jié)構(gòu)對(duì)于電催化性能影響的機(jī)理,測(cè)試顯示鉑八足納米晶對(duì)甲酸氧化性能最優(yōu)。本方法為復(fù)雜納米機(jī)構(gòu)的合成和性能的研究開辟了新的視野。 2、凹面立方鉑-氧化石墨烯復(fù)合材料的可控合成與電催化性能的研究：當(dāng)前在燃料電池中,納米Pt催化劑用作氧化還原反應(yīng)(ORR),但是同時(shí)實(shí)現(xiàn)穩(wěn)定性和高活性仍然是個(gè)富有挑戰(zhàn)性的工作。在本工作中,我們合成一種高度凹陷且具有高指數(shù)晶面的納米立方塊(HCC)。通過與石墨烯自組裝形成復(fù)合催化劑可以顯著提高Pt HCC的穩(wěn)定性,同時(shí)體現(xiàn)出非常高的催化性能,比商業(yè)用的Pt/C催化劑的催化性能高了7倍。在催化劑使用量為46μgcm-2的情況下,半波電位(E1/2)仍然可以達(dá)到0.967V,比Pt/C高63mV,甚至優(yōu)于文獻(xiàn)最高紀(jì)錄多孔納米Pt-Ni。這個(gè)工作為基于惰性載體的貴金屬納米催化劑的催化性能調(diào)控開辟了新思路。 3、鉑多足立方分支結(jié)構(gòu)的鎳離子輔助合成與電催化性能的研究：Pt(100)面通常被認(rèn)為在氧還原反應(yīng)(ORR)中活性較低。本論文報(bào)道的是一個(gè)獨(dú)特的Pt多足立方分支納米結(jié)構(gòu),其表面主要由{100}面構(gòu)成,但在立方體之間連接部分具有少量高指數(shù)晶面。其合成過程是通過Ni2+為介質(zhì)從多枝狀結(jié)構(gòu)的高指數(shù){311}面轉(zhuǎn)變到{100}面。盡管其表面由{100}面覆蓋,鉑多足立方體依然表現(xiàn)出較高的ORR活性,其半電位和電流密度與活性最高的鉑鎳合金催化劑的性能接近,而且該催化劑催化穩(wěn)定性強(qiáng)。該表面演變實(shí)現(xiàn)了一種調(diào)節(jié)低指數(shù)晶面與高指數(shù)晶面比例的方式。本論文的結(jié)果表明,Pt多足立方分支結(jié)構(gòu)的優(yōu)異ORR性能是高指數(shù)晶面的高催化活性和低指數(shù)平整晶面與電極的低接觸電阻相結(jié)合的結(jié)果。本論文提出一種晶面控制和ORR催化劑設(shè)計(jì)的新方法。 4、具有高指數(shù)晶面的銅鉑合金的可控合成：Pt以其高效的催化性能而廣泛應(yīng)用在質(zhì)子交換薄膜燃料電池中,但其昂貴的價(jià)格制約了燃料電池的進(jìn)一步商業(yè)化推廣,因此提高Pt的催化活性以降低成本顯得意義重大。目前主要采用兩種方式來提高Pt的催化性能：(1)Pt與其它金屬M(fèi) (M=Pd、Co、Ni、Fe、Au、 Cu)等形成基于Pt的合金；(2)在合成體系中加入表面保護(hù)劑,合成出具有高指數(shù)晶面的鉑納米晶。但這兩種方法都存在著嚴(yán)重的不足,這也使得合金催化的研究尚不夠成熟。本課題在結(jié)合前人研究的基礎(chǔ)上開發(fā)出一種合成銅鉑合金的新方法,為制備具有高效催化活性的合金開辟了新的視野。
[Abstract]:The increasing use of fossil energy not only improves the quality of our lives, but also brings serious environmental pollution. Therefore, developing a green energy is the only way to alleviate the current environmental crisis. However, the high efficiency of proton exchange fuel cell depends on expensive platinum and platinum-based precious metal catalysts, which seriously hinder the large-scale application of proton exchange fuel cell. Therefore, the main content of proton exchange fuel cell research is to improve the catalytic activity of platinum. In this paper, a series of fuel cell catalysts with high catalytic activity were developed by adjusting the synthesis parameters in the simple system of water-ethylene glycol.
1. Controlled synthesis and electrocatalytic properties of platinum multipedal branched nanostructures: Surface parameters (especially specific surface area, surface atom distribution) of nanocrystals are important factors affecting the performance of nanocatalysts. The structural characteristics of branched nanostructures make them have good catalytic performance, but it is difficult to separate them in practical synthesis. In this work, the controllable synthesis of PT nanostructures with different number of branches was achieved by controlling the amount of HCl added in the synthesis process. In this reaction, oxidation and etching of HCl play three roles in the synthesis of nanocrystals: (1) regulating the crystallinity of nanocrystals and seeds; (2) regulating {111}, {111}, { The number of 100} crystal planes; (3) the concentration of newly supplied atoms is regulated. Therefore, the tripod, quadruped, hexapod and Octopod PT nano-branching structures can be synthesized by controlling the amount of HCl etchant added. This controlled synthesis method reveals the mechanism of the effect of the structure on the electrocatalytic performance, and tests show that platinum Octopod nano-branching structures can be synthesized. This method opens up a new field of vision for the synthesis and properties of complex nanostructures.
2. Controlled synthesis and Electrocatalytic Performance of concave cubic platinum-graphene oxide composites: Nowadays, nano-Pt catalysts are used as redox reactions (ORR) in fuel cells, but achieving stability and high activity at the same time is still a challenging task. In this work, we synthesized a highly concave and high-finger composite. Nano-cubic block (HCC) with several crystal planes. The stability of Pt HCC can be significantly improved by self-assembly with graphene to form a composite catalyst, which exhibits very high catalytic performance. The catalytic performance of the composite catalyst is seven times higher than that of commercial Pt/C catalyst. V, 63 mV higher than Pt/C, and even better than the highest-recorded porous nano-Pt-Ni in the literature. This work opens up a new way to control the catalytic performance of noble metal nanocatalysts based on inert carriers.
3. Nickel ion-assisted synthesis and electrocatalytic properties of platinum polypod cubic branched structures: Pt (100) surfaces are generally considered to be less active in oxygen reduction reactions (ORR). The synthesis process is from the high exponential {311} plane of multi-branched structure to {100} plane with Ni2+ as the medium. Despite its surface being covered by {100} surface, the platinum polypod cube still exhibits high ORR activity, and its half potential and current density are close to those of the most active platinum-nickel alloy catalysts, and the catalytic performance of the catalyst is similar to that of the most active platinum-nickel alloy catalysts. The results show that the excellent ORR performance of Pt polypod cubic bifurcation structure is the combination of high catalytic activity of high exponential crystal plane and low exponential flat crystal plane with low contact resistance of electrode. A new method of surface control and ORR catalyst design.
4. Controllable synthesis of copper-platinum alloys with high exponential crystal planes: Pt is widely used in proton exchange membrane fuel cells because of its high catalytic performance, but its high price restricts the further commercialization of fuel cells, so it is important to improve the catalytic activity of Pt to reduce costs. In order to improve the catalytic performance of Pt, Pt forms Pt-based alloys with other metals M (M = Pd, Co, Ni, Fe, Au, Cu) and so on; (2) Pt nanocrystals with high exponential planes were synthesized by adding surface protectors in the synthesis system. However, there are serious shortcomings in both methods, which makes the study of alloy catalysis not mature enough. A new method for synthesizing copper-platinum alloys was developed on the basis of previous studies, which opened up a new field of vision for the preparation of alloys with high catalytic activity.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：O643.36;TM911.4
本文編號(hào)：2247548
[Abstract]:The increasing use of fossil energy not only improves the quality of our lives, but also brings serious environmental pollution. Therefore, developing a green energy is the only way to alleviate the current environmental crisis. However, the high efficiency of proton exchange fuel cell depends on expensive platinum and platinum-based precious metal catalysts, which seriously hinder the large-scale application of proton exchange fuel cell. Therefore, the main content of proton exchange fuel cell research is to improve the catalytic activity of platinum. In this paper, a series of fuel cell catalysts with high catalytic activity were developed by adjusting the synthesis parameters in the simple system of water-ethylene glycol.
1. Controlled synthesis and electrocatalytic properties of platinum multipedal branched nanostructures: Surface parameters (especially specific surface area, surface atom distribution) of nanocrystals are important factors affecting the performance of nanocatalysts. The structural characteristics of branched nanostructures make them have good catalytic performance, but it is difficult to separate them in practical synthesis. In this work, the controllable synthesis of PT nanostructures with different number of branches was achieved by controlling the amount of HCl added in the synthesis process. In this reaction, oxidation and etching of HCl play three roles in the synthesis of nanocrystals: (1) regulating the crystallinity of nanocrystals and seeds; (2) regulating {111}, {111}, { The number of 100} crystal planes; (3) the concentration of newly supplied atoms is regulated. Therefore, the tripod, quadruped, hexapod and Octopod PT nano-branching structures can be synthesized by controlling the amount of HCl etchant added. This controlled synthesis method reveals the mechanism of the effect of the structure on the electrocatalytic performance, and tests show that platinum Octopod nano-branching structures can be synthesized. This method opens up a new field of vision for the synthesis and properties of complex nanostructures.
2. Controlled synthesis and Electrocatalytic Performance of concave cubic platinum-graphene oxide composites: Nowadays, nano-Pt catalysts are used as redox reactions (ORR) in fuel cells, but achieving stability and high activity at the same time is still a challenging task. In this work, we synthesized a highly concave and high-finger composite. Nano-cubic block (HCC) with several crystal planes. The stability of Pt HCC can be significantly improved by self-assembly with graphene to form a composite catalyst, which exhibits very high catalytic performance. The catalytic performance of the composite catalyst is seven times higher than that of commercial Pt/C catalyst. V, 63 mV higher than Pt/C, and even better than the highest-recorded porous nano-Pt-Ni in the literature. This work opens up a new way to control the catalytic performance of noble metal nanocatalysts based on inert carriers.
3. Nickel ion-assisted synthesis and electrocatalytic properties of platinum polypod cubic branched structures: Pt (100) surfaces are generally considered to be less active in oxygen reduction reactions (ORR). The synthesis process is from the high exponential {311} plane of multi-branched structure to {100} plane with Ni2+ as the medium. Despite its surface being covered by {100} surface, the platinum polypod cube still exhibits high ORR activity, and its half potential and current density are close to those of the most active platinum-nickel alloy catalysts, and the catalytic performance of the catalyst is similar to that of the most active platinum-nickel alloy catalysts. The results show that the excellent ORR performance of Pt polypod cubic bifurcation structure is the combination of high catalytic activity of high exponential crystal plane and low exponential flat crystal plane with low contact resistance of electrode. A new method of surface control and ORR catalyst design.
4. Controllable synthesis of copper-platinum alloys with high exponential crystal planes: Pt is widely used in proton exchange membrane fuel cells because of its high catalytic performance, but its high price restricts the further commercialization of fuel cells, so it is important to improve the catalytic activity of Pt to reduce costs. In order to improve the catalytic performance of Pt, Pt forms Pt-based alloys with other metals M (M = Pd, Co, Ni, Fe, Au, Cu) and so on; (2) Pt nanocrystals with high exponential planes were synthesized by adding surface protectors in the synthesis system. However, there are serious shortcomings in both methods, which makes the study of alloy catalysis not mature enough. A new method for synthesizing copper-platinum alloys was developed on the basis of previous studies, which opened up a new field of vision for the preparation of alloys with high catalytic activity.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：O643.36;TM911.4
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 衣寶廉;燃料電池的原理、技術(shù)狀態(tài)與展望[J];電池工業(yè);2003年01期
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