本文選題：燃料電池 + 氧還原�。� 參考：《重慶大學(xué)》2014年博士論文

【摘要】：質(zhì)子交換膜燃料電池（PEMFC）具有高效和潔凈等突出優(yōu)點(diǎn)，是最有發(fā)展前途的一種動(dòng)力電池，可廣泛用于移動(dòng)電源和便攜式電源。目前，PEMFCs主要催化劑為貴金屬Pt類催化劑。然而，Pt儲(chǔ)量低、價(jià)格高等問(wèn)題嚴(yán)重阻礙了PEMFCs的商業(yè)化進(jìn)程。開(kāi)發(fā)高效低成本的非鉑催化劑替代Pt類催化劑催化氧還原反應(yīng)（ORR）是成功實(shí)現(xiàn)燃料電池商業(yè)化的關(guān)鍵。近年來(lái)，非鉑催化劑的ORR催化活性已有大幅提高，但仍與Pt基催化劑有很大差距。如何提高非鉑催化劑在大電流工況下的催化活性已成為非Pt催化劑實(shí)際應(yīng)用的關(guān)鍵�；诖耍骄糠墙饘俅呋瘎┑幕钚灾行�、開(kāi)發(fā)提高活性位密度的先進(jìn)制備技術(shù)、構(gòu)筑高效非鉑催化電極結(jié)構(gòu)是當(dāng)前非鉑催化劑研究的主要方向。 本文開(kāi)展了如下幾方面的研究工作： （1）開(kāi)發(fā)高活性高穩(wěn)定的Pd類催化劑。Pd的催化性質(zhì)與Pt類似，而其儲(chǔ)量是Pt的50倍，價(jià)格為Pt的1/3，被認(rèn)為是替代Pt催化劑降低成本的最優(yōu)選擇之一。然而，相比Pt催化劑Pd催化劑的氧還原催化活性低，穩(wěn)定性差。本文第三章中，開(kāi)展基于金屬/氧化物載體界面價(jià)鍵調(diào)控鈀電子結(jié)構(gòu)增強(qiáng)活性和穩(wěn)定性的研究：研究通過(guò)單片層蒙脫土載體（ex-MMT）調(diào)控Pd的表面電子結(jié)構(gòu)，使其d帶中心更趨近與Pt，降低其氧中間物種吸附能，獲得了一種催化活性與Pt類似、穩(wěn)定性優(yōu)異的Pd/ex-MMT催化劑。研究發(fā)現(xiàn)，界面共價(jià)氧化物的形成，是活性穩(wěn)定性增強(qiáng)的主要原因。該研究為優(yōu)化Pd表面電子結(jié)構(gòu)、提高Pd催化活性穩(wěn)定性提出了一種新方法。在燃料電池中應(yīng)用該催化劑，可降低20%燃料電池的成本。 （2）探究非金屬氮摻雜碳陰極催化劑的氮鍵合結(jié)構(gòu)與活性的關(guān)系，開(kāi)發(fā)選擇性摻氮技術(shù)。氮摻雜石墨烯具有比表面積高、導(dǎo)電性高等特點(diǎn)。但是，其制備過(guò)程復(fù)雜、活性位點(diǎn)不明、酸性介質(zhì)中活性差，使其難于作為ORR催化劑商業(yè)化應(yīng)用。本文第四章中，開(kāi)展空間限制-誘導(dǎo)合成平面吡啶吡咯氮摻雜的石墨烯以及其氧還原催化性能的研究：開(kāi)發(fā)了一種簡(jiǎn)單易行成本低廉的方法制備石墨烯，即通過(guò)扁平納米反應(yīng)器制備氮摻雜石墨烯。具有平面結(jié)構(gòu)的吡啶吡喏氮（Planar N）以p電子參與石墨烯π共軛體系，，有助于與之相鄰的碳原子活化和石墨烯導(dǎo)電性的提高。季氨氮?jiǎng)t由于其鍵角影響，形成三維立體結(jié)構(gòu)破壞石墨烯局部π共軛體系，從而影響導(dǎo)電性。本研究通過(guò)調(diào)節(jié)納米反應(yīng)器的寬度，可選擇性的合成具有平面結(jié)構(gòu)的吡啶氮和吡喏氮摻雜的石墨烯。通過(guò)不同平面氮含量的氮摻雜石墨烯，構(gòu)建平面氮—導(dǎo)電性—催化活性之間的構(gòu)效關(guān)系。其中，ORR活性最高的氮摻雜石墨烯平面氮含量高達(dá)93%，其催化氧還原半波電位與商業(yè)化Pt/C催化劑僅相差60mV，單電池測(cè)試的最大功率可達(dá)340mW·cm-2。該方法所制備的石墨烯具有良好的導(dǎo)電性和酸性條件下優(yōu)異的ORR催化活性。 （3）開(kāi)發(fā)高利用率高活性位點(diǎn)密度的PEMFC陰極電極。構(gòu)建高效氧還原催化電極，除引入更多活性位點(diǎn)外，活性位點(diǎn)的暴露同樣非常重要。本文第五章中，開(kāi)展了基于形態(tài)控制轉(zhuǎn)換納米聚合物制備高效氧還原碳納米材料催化劑的研究：研究通過(guò)氯化鈉重結(jié)晶方法以固定前驅(qū)聚合物的納米形態(tài)，通過(guò)熱解，獲得具有優(yōu)異孔結(jié)構(gòu)、表面性質(zhì)的催化劑。該催化劑保持原前驅(qū)物的幾何形貌和孔結(jié)構(gòu)。氯化鈉晶體為催化劑石墨化和氮摻雜提供全封閉的反應(yīng)空間。優(yōu)異的三維傳輸通道、高度石墨化的碳結(jié)構(gòu)以及活性氮摻雜的表面性質(zhì)，極大增加了暴露在催化三相界面的活性位點(diǎn)數(shù)量。以該催化劑制備的陰極電極，其最高功率達(dá)600mV·cm-2，與Pt/C催化劑的ORR活性處于同一個(gè)數(shù)量級(jí)。開(kāi)發(fā)的此類新型材料已經(jīng)具備了在燃料電池發(fā)動(dòng)機(jī)中完全替代Pt/C催化劑的可能性。
[Abstract]:Proton exchange membrane fuel cell (PEMFC) has the outstanding advantages of high efficiency and cleanliness. It is one of the most promising power batteries, which can be widely used in mobile and portable power sources. At present, the main catalyst of PEMFCs is Pt catalyst of precious metals. However, the low Pt reserves and high price have seriously hindered the commercialization of PEMFCs. The key to commercialization of fuel cells is the high efficiency and low cost non platinum catalyst instead of Pt catalyst (ORR). In recent years, the ORR catalytic activity of non platinum catalysts has been greatly improved, but there is still a big gap with the Pt based catalyst. How to improve the catalytic activity of the non platinum catalyst in the high current condition has become a great problem. The key to the practical application of non Pt catalysts is to explore the active center of non-metallic catalysts, to develop advanced preparation techniques for increasing the density of active sites, and to construct a high efficiency non platinum catalytic electrode structure is the main direction of the current research on non platinum catalysts.
This article has carried out the following aspects of research work:
(1) the catalytic properties of the highly active and highly stable Pd catalyst.Pd are similar to that of Pt, and their reserves are 50 times of Pt and the price is Pt, which is considered to be one of the best alternatives for reducing the cost of the Pt catalyst. However, the catalytic activity of the Pt catalyst Pd catalyst is low and the stability is poor. In this third chapter, metal / oxygen is carried out in the third chapter. Study on the regulation of the enhanced activity and stability of the palladium electronic structure by the interface valence bond of the material carrier: the study of the surface electronic structure of Pd by single layer montmorillonite (ex-MMT), which makes the center of the D closer to and Pt, reduces the adsorption energy in the intermediate oxygen species, and has obtained a kind of Pd/ex-MMT catalyst, which has a similar catalytic activity with Pt and has excellent stability. It is found that the formation of covalent oxide at the interface is the main reason for the enhancement of the activity stability. A new method is proposed to optimize the electronic structure of the Pd surface and improve the stability of the catalytic activity of Pd. The application of the catalyst in fuel cells can reduce the cost of 20% fuel cells.
(2) to explore the relationship between nitrogen bonding structure and activity of non-metallic nitrogen doped carbon cathode catalyst and the development of selective nitrogen doping technology. Nitrogen doped graphene has high specific surface area and high conductivity. However, the preparation process is complex, the active site is unknown, and the activity of acid medium is poor, so it is difficult to be used as the commercial application of ORR catalyst. In the fourth chapter, space restriction - induced synthesis of planar pyridine pyrrole - doped graphene and its catalytic performance in oxygen reduction are studied. A simple and inexpensive method is developed to prepare graphene, that is, the preparation of nitrogen doped graphene through a flat nano reactor. The planar structure of pyridine pyridine nitrogen (Planar N) with P electricity The participation of the son in the graphene pi conjugation system is helpful to the activation of the adjacent carbon atoms and the increase of the conductivity of graphene. The quaternary ammonium nitrogen, because of its bond angle, forms a three-dimensional structure that destroys the local pi conjugation system of graphene, thus affecting the conductivity. The structure-activity relationship between planar nitrogen doping and catalytic activity was constructed by different planar nitrogen content of nitrogen doped graphene. Among them, the nitrogen content of nitrogen doped graphene with the highest ORR activity was up to 93%, and the catalytic oxygen reduction half wave potential was only 60mV with commercial Pt/C catalyst. The maximum power of the single cell test can reach 340mW. Cm-2.. The graphene prepared by this method has good conductivity and excellent ORR catalytic activity under acidic conditions.
(3) developing a PEMFC cathode electrode with high active site density and high active site density. Construction of a high performance oxygen reduction catalytic electrode is also very important. In addition to the introduction of more active sites, the exposure of active sites is also very important. In the fifth chapter, a study on the preparation of high effect oxygen reduction carbon nanomaterials based on morphologic control conversion nanoparticles was carried out. The nano morphology of precursor polymers was immobilized by sodium chloride recrystallization. By pyrolysis, a catalyst with excellent pore structure and surface properties was obtained. The catalyst maintains the geometric morphology and pore structure of the precursor. The NaCl crystal provides a completely closed reaction space for the catalyst graphitization and nitrogen doping. The highly graphitized carbon structure and the surface properties doped by active nitrogen greatly increase the number of active sites exposed to the catalytic three-phase interface. The cathode electrode prepared by this catalyst has the highest power of 600mV. Cm-2, and the ORR activity of the Pt/C catalyst is in the same number of orders. The possibility of completely replacing Pt/C catalyst in fuel cell engine.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：O643.36;TM911.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 羅瑾;楊樂(lè)夫;陳秉輝;鐘傳建;;三元合金氧還原電催化劑(英文)[J];電化學(xué);2012年06期

2 呂海峰;程年才;木士春;潘牧;;質(zhì)子交換膜燃料電池Pd修飾Pt/C催化劑的電催化性能[J];化學(xué)學(xué)報(bào);2009年14期

3 ;DFT study of difference caused by catalyst supports in Pt and Pd catalysis of oxygen reduction reaction[J];Science in China(Series B:Chemistry);2009年05期

4 ;Morphology control and shape evolution in 3D hierarchical superstructures[J];Science China(Chemistry);2012年11期

本文編號(hào)：2060014