本文選題：微波輔助加熱　切入點(diǎn)：電催化劑　出處：《深圳大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：石油資源的日益匱乏和溫室氣體排放所引起的地球暖化的加劇,使綠色環(huán)保的新型能源與技術(shù)的開發(fā)和利用成為十分迫切需要研究的課題。有機(jī)體系鋰空氣電池因具有巨大的比容量而有著重要的應(yīng)用前景�？諝怆姌O是電池反應(yīng)的主要場(chǎng)所,不僅提高電極反應(yīng)(氧還原和氧析出反應(yīng))效率,而且可降低電極過電位,所以提高電池的能量效率和循環(huán)性能已經(jīng)成為了有機(jī)體系鋰空氣電池發(fā)展和應(yīng)用的過程中亟待解決的關(guān)鍵問題。研究表明,在電池正極中加入合適的電催化劑能夠有效地降低電化學(xué)反應(yīng)極化,提高電池充放電與循環(huán)性能。石墨烯材料具有結(jié)構(gòu)規(guī)整、制備可控等優(yōu)點(diǎn),不但可以作為載體來制備擔(dān)載型電催化劑,而且還可以作為一個(gè)理想的模型體系來研究擔(dān)載型催化劑的活性、穩(wěn)定性及催化機(jī)理等。(1)采用微波輻射技術(shù),將氧化石墨烯與固相硫源及氮硫源的混合物加熱,一步實(shí)現(xiàn)氧化石墨烯的還原及異質(zhì)原子的摻雜。實(shí)驗(yàn)結(jié)果表明,通過微波加熱能夠在很短的時(shí)間內(nèi)制備出摻雜的石墨烯,異質(zhì)原子摻雜后石墨烯的(002)衍射峰發(fā)生了偏移,其強(qiáng)度也隨著氮硫前驅(qū)體加入量的增加而逐漸增強(qiáng)。石墨烯摻雜前后的形貌并無大的變化,說明采用固相法也能夠得到比表面積大、層數(shù)較少的石墨烯,而摻雜后石墨烯中缺陷度有所增加,當(dāng)氧化石墨與硫脲的質(zhì)量比為3:1時(shí),其拉曼譜圖的D峰與G峰的強(qiáng)度比約為0.99,大于未摻雜石墨烯(0.81),此時(shí)摻雜石墨烯表現(xiàn)出最好的氧還原催化活性。利用微波加熱與化學(xué)還原相結(jié)合,可以在短時(shí)間內(nèi)還原合金并負(fù)載在摻雜或未摻雜石墨烯上。結(jié)果發(fā)現(xiàn),當(dāng)鈀鎢物質(zhì)的量之比為3:1,且鈀鎢合金負(fù)載在石墨烯上的量為20%時(shí),表現(xiàn)出最優(yōu)的催化性能。(2)采用微波輔助與化學(xué)還原相結(jié)合方法制備硫摻雜石墨烯擔(dān)載鈀鎢合金(Pd3W-SG)電催化劑。實(shí)驗(yàn)表明:1、合成的鈀鎢合金雜質(zhì)相少、結(jié)晶度高,并且合金顆粒均勻分散在硫摻雜石墨烯表面;2、在堿性電解液中進(jìn)行氧還原反應(yīng)(ORR)循環(huán)伏安(CV)測(cè)試,Pd3W-SG相對(duì)于其他樣品來說,表現(xiàn)出更正的起始電位(-0.02 V),而其它樣品起始電位分別為Pd-SG(-0.12 V)、Pd-G(-0.12 V)、SG(-0.19 V)與G(-0.21 V),表明摻雜石墨烯擔(dān)載鈀鎢合金電催化劑具有更高的ORR催化活性。3、旋轉(zhuǎn)圓盤電極(RDE)與旋轉(zhuǎn)環(huán)盤電極(RRDE)測(cè)試中,該電催化劑表現(xiàn)出接近4的轉(zhuǎn)移電子數(shù),與商業(yè)鉑碳(Pt/C)催化劑相當(dāng);4、Pd3W-SG與商業(yè)Pt/C的抗毒化性測(cè)試中,在加入甲醇后其電流密度僅改變0.04706 mA/cm2,而商業(yè)鉑碳則改變0.09094mA/cm2;5、Pd3W-SG與商業(yè)Pt/C的穩(wěn)定性測(cè)試中,Pd3W-SG的峰值電位電流密度僅改變0.01854 mA/cm2,而鉑碳則改變0.07669 mA/cm2;6、在放電電流密度為100 mA/g時(shí),使用Pd3W-SG催化劑為正極的鋰空氣電池具有更高的比容量(5660.8 mAh/g)及循環(huán)壽命。(3)采用微波輔助與化學(xué)還原相結(jié)合方法制備了氮硫摻雜石墨烯擔(dān)載鈀鎢合金(Pd3W-NSG)樣品。實(shí)驗(yàn)表明:1、摻雜石墨烯中引入的異質(zhì)原子或缺陷能夠改善擔(dān)載顆粒的生長(zhǎng),使鈀鎢合金顆粒能夠勻分散在NSG上;2、Pd-G、Pd-NSG與Pd3W-NSG樣品的合金顆粒大小分別為14.33、32.8及20.3 nm,小尺寸的納米顆粒具有更大的比表面積,能夠有效提高催化劑的電化學(xué)反應(yīng)活性面積,從而提高其催化活性;3、在堿性條件下進(jìn)行ORR的CV測(cè)試,Pd3W-NSG表現(xiàn)出比其他樣品更正的起始電位(-0.014 V),而其它樣品分別為Pd-NSG(-0.126 V)、Pd-G(-0.143 V)、NSG(-0.187 V)與G(-0.204V)。RDE與RRDE測(cè)試,Pd3W-NSG電催化劑表現(xiàn)出接近4的轉(zhuǎn)移電子數(shù);4、進(jìn)行抗毒化性測(cè)試時(shí),Pd3W-NSG表現(xiàn)出比商業(yè)Pt/C要強(qiáng)的耐毒化性,加入甲醇后Pt/C的電流密變化比Pd3W-NSG要高0.06592 mA/cm2;5、進(jìn)行10000次的CV循環(huán)穩(wěn)定性測(cè)試時(shí),Pd3W-NSG的峰值電位電流密度只改變了0.01819 mA/cm2;6、在放電電流密度為100 mA/g時(shí),使用Pd3W-NSG催化劑正極的鋰空氣電池表現(xiàn)出高的比容量(7441.1mAh/g);這些結(jié)果都證明Pd3W-NSG具有降低氧還原活化能及鋰空氣電池中充電產(chǎn)物分解活化能,從而提高電極反應(yīng)催化性能的作用;7、進(jìn)行掃描電化學(xué)顯微鏡(SECM)測(cè)試中,Pd3W-NSG表現(xiàn)出最高的催化活性。
[Abstract]:The growing shortage of oil resources and greenhouse gas emissions caused by global warming intensifies, the development of new energy technology and green environmental protection and utilization is an urgent need to study. The organic system lithium air battery because of its huge capacity and have important application prospect. The air electrode is the main place for cell reaction that not only improve the electrode reaction (reduction of oxygen and oxygen evolution reaction) efficiency, but also reduce the overpotential, so to improve the energy efficiency and the cycle performance of the battery has become the key problem to be solved in the process of organic system lithium air battery development and application. The results show that adding suitable catalysts in battery anode can effectively reduce the electrochemical polarization, improve the battery charge and discharge cycle performance. The graphene material has a regular structure, controllable preparation etc., but can not As a carrier for the preparation of supported catalysts, but also can be used as an ideal model system to study the supported catalyst activity, stability and catalytic mechanism. (1) using the technique of microwave radiation, graphene oxide and solid sulfur sources and sulfur and nitrogen source mixture heating step to achieve reduction of graphene oxide and hetero atoms. The experimental results show that the prepared graphene doped in a very short period of time can be heated by microwave, the graphene doped (002) after the shift of diffraction peaks, the intensity is increased with the amount of nitrogen and sulfur precursor increases there is no change. The morphology of graphene doped before and after the show by solid state method can obtain a large surface area, the graphene layers less, and doped in graphene defects increased, when the graphite oxide and thiourea mass ratio was 3:1, The ratio of the intensity of the Raman spectrum of D peak and G peak figure of 0.99, higher than the undoped graphene (0.81), the doped graphene exhibits the best catalytic activity for oxygen reduction. The use of microwave heating and chemical reduction combined with alloy can be reduced in a short period of time and load in doped or undoped graphene. The results showed that when the molar ratio of tungsten palladium and palladium tungsten alloy is 3:1, load on the Shi Moxi quantity was 20%, showed the optimal catalytic performance. (2) by microwave assisted chemical reduction combined with preparation method of sulfur doped graphene supported palladium tungsten alloy (Pd3W-SG) catalysts the experiment shows: 1. The synthesis of palladium, tungsten alloy impurity phase, high crystallinity, and alloy particles uniformly dispersed in the sulfur doped graphene surface; 2 of the oxygen reduction reaction in alkaline electrolyte (ORR) cyclic voltammetry (CV) test, Pd3W-SG compared to the other samples, showing more The initial potential positive (-0.02 V), while the other samples were Pd-SG (-0.12 initial potential V), Pd-G (-0.12 V), SG (-0.19 V) and G (-0.21 V), showed that doped graphene supported palladium tungsten alloy electrocatalyst has higher catalytic activity of ORR.3, a rotating disc electrode (RDE) and rotating ring disk electrode (RRDE) test, the electro catalyst showed near the number of electron transfer 4, and commercial carbon platinum (Pt/C) catalyst; 4, test of Pd3W-SG and anti drug commercial Pt/C, the current density in methanol after changing only 0.04706 mA/cm2, while the commercial platinum carbon changing 0.09094mA/cm2; 5, the stability test of Pd3W-SG and commercial Pt/C, the peak potential Pd3W-SG current density change only 0.01854 mA/cm2, and 0.07669 mA/cm2 platinum carbon change; 6, the discharge current density of 100 mA/g, using Pd3W-SG as catalyst is the lithium air battery has higher specific capacity (5660.8 mAh/ G) and cycle life. (3) by microwave assisted chemical reduction method and combination of nitrogen and sulfur doped graphene supported palladium tungsten alloy prepared (Pd3W-NSG) samples. Experimental results show that: 1, the introduction of doped graphene in heterogeneous atoms or defects can improve the loading of particle growth, the palladium particles of tungsten alloy can be evenly dispersed in NSG; 2, Pd-G, Pd-NSG and Pd3W-NSG alloy particle size samples were 14.33,32.8 and 20.3 nm, the small size of the nanoparticles has larger specific surface area, can effectively improve the electrochemical active area of catalyst, so as to improve its catalytic activity; 3, ORR CV test in alkaline under the condition of Pd3W-NSG showed the initial potential than other samples (-0.014, V) corrections and other samples were Pd-NSG (-0.126 V), Pd-G (-0.143 V), NSG (-0.187 V) and G (-0.204V).RDE and RRDE test, Pd3W-NSG electrocatalyst showed near transfer electric 4 Number 4, of antivenom; test, Pd3W-NSG showed stronger resistance to poisoning than commercial Pt/C, methanol Pt/C after current density variation is 0.06592 higher than the Pd3W-NSG mA/cm2; 5, CV test cycle stability 10000 times, the peak potential current density Pd3W-NSG only changed 0.01819 mA/cm2; 6 in the discharge, the current density is 100 mA/g, using the Pd3W-NSG catalyst electrode of lithium air battery shows high specific capacity (7441.1mAh/g); these results show that Pd3W-NSG can reduce the activation energy for oxygen reduction and lithium air battery charging product decomposition activation energy, so as to improve the catalytic performance of electrode reaction; 7, scanning electrochemical microscope (SECM) test, Pd3W-NSG exhibited the highest catalytic activity.

【學(xué)位授予單位】：深圳大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36;TM912

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 王玉嬌;王瑋;馮平源;王康麗;程時(shí)杰;蔣凱;;掃描電化學(xué)顯微鏡技術(shù)在鋰離子電池分析中的研究進(jìn)展[J];儲(chǔ)能科學(xué)與技術(shù);2017年01期

2 王凱;季炳成;韓美佳;李立偉;;微波固相法快速制備氮摻雜石墨烯[J];無機(jī)化學(xué)學(xué)報(bào);2013年10期

3 尹其和;;掃描電化學(xué)顯微鏡的基本原理與應(yīng)用[J];中山大學(xué)研究生學(xué)刊(自然科學(xué).醫(yī)學(xué)版);2011年02期

，

本文編號(hào)：1565486