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多孔碳及其纳米复合材料的合成与电催化应用研究

Preparation and Electrocatalysis Application Study of Porous Carbon and Its Nanocomposite Materials

【作者】 王欢

【导师】 郭黎平;

【作者基本信息】 东北师范大学 , 分析化学, 2014, 博士

【摘要】 随着碳纳米材料的迅猛发展,多孔碳纳米材料因为存在大量的孔,高的比表面积和独特的构架组成已经在各种不同的领域引起了研究者们的极大兴趣。近些年来,多孔碳纳米材料更广泛的被应用在电化学领域,例如用作电催化的催化剂和电容器的电极材料等。本论文在前人研究的基础上,制备了几种新型的多孔碳及其纳米复合材料并对其电催化应用进行研究,内容主要包括以下几个部分:(1)通过自模板方法合成了一种新型的介孔碳纳米纤维(M-CNF),将其修饰到电极上用来电化学检测多巴胺(DA),抗坏血酸(AA)和尿酸(UA),M-CNF/GCE对这些物质呈现出显著增强的电催化性能。而且,这种碳材料实现了在生理pH条件下(pH7.4)同时检测DA,AA和UA混合物,呈现出高的灵敏度和宽的线性范围。我们用M-CNF/GCE对嘌呤类物质进行了检测,优越的电催化性能表明M-CNF是一种有前途的电催化剂。进一步,我们将M-CNF作为载体,将金纳米粒子通过电沉积方法负载到M-CNF上,结合M-CNF独特的结构和高的表面积以及金纳米粒子高的催化性能,M-CNF-Au检测肼呈现出低的检出限,宽的线性范围和短的响应时间,这使M-CNF-Au成为有前途的高效检测肼的修饰电极材料。而且,此纳米复合物的制备在设计和构建基于M-CNF的电催化材料上有很大的指导意义。(2)我们制备了铂钯负载的大介孔碳(PtxPdy/LMC)纳米复合物,并将其应用于电化学,用H2O2和亚硝酸盐作为探针检测PtxPdy/LMC的电催化性能。H2O2和亚硝酸盐在PtxPdy/LMC/GCE上的检测结果表明Pt1Pd1/LMC/GCE呈现出较高的电催化活性。Pt, Pd合金纳米粒子高效催化能力和协同效应以及LMC基底的独特结构是Pt1Pd1/LMC/GCE产生增强的电催化性能的原因。Pt1Pd1/LMC/GCE不仅可以作为H2O2和亚硝酸盐的优良传感器而且可以作为检测其他物质的高效电催化剂。受大介孔碳制备方法的启发,我们以鱼精DNA为碳源和氮源实现了一步绿色法制备氮掺杂的大介孔碳(N-LMC)。研究了它对氧还原反应(ORR)的催化活性,与未掺氮的大介孔碳相比,有较高吡啶氮和石墨化氮含量的N-LMC-800(800℃碳化)显示出更高的ORR电催化活性,表明它是一种有前途的非金属氧还原电催化剂。(3)通过在有序介孔碳(OMC)制备过程中加入不同含量比的蔗糖和二苄基硫,成功的合成了不同量硫掺杂的有序介孔碳(OMC-S-X)。其中得到的OMC-S-3对ORR呈现出高的电催化活性,好的稳定性和优良的抗甲醇干扰能力。而且,我们研究了在OMC-S-X中不同的硫键对ORR的影响,结果表明C-S-C对ORR起着很重要的作用。(4)以聚多巴胺为前驱体,制备了钴掺杂的纳米孔空心碳球(PDA-HCS-Co)。虽然PDA-HCS对ORR有很小的催化活性,PDA-HCS-Co却呈现出与Pt-C催化剂相近的电催化活性,而且有高于Pt-C催化剂的稳定性和抗甲醇干扰能力。这表明结合了氮元素和Co-N对ORR的催化优势,我们合成的PDA-HCS-Co是一种有前途的非贵金属氧还原催化剂。(5)我们报导了一种合理的设计和制备新型孔石墨烯(P-GR)的方法,其中使用铜作为侵蚀试剂。不同的电活性化合物在P-GR/GCE上的电化学行为表明,与GR/GCE相比,P-GR/GCE有更好的电催化性能。这些生物分子在P-GR/GCE上增强的电化学活性归因于与GR相比,P-GR独特的孔结构,高含量的边缘缺陷位点(EDSs)和较多的酸性含氧官能团。该工作具有很重要的意义,不仅仅因为它是一种新型的制备P-GR的方法,更重要的是它构建了一种基于P-GR的新型的电化学传感平台,扩展了P-GR的应用范围。

【Abstract】 With the development of carbon nanomaterials, owing to their massive pores, highspecific surface area and unique frame, porous carbon nanomaterials have received a greatdeal of attention in different fields. Recent years, porous carbon nanomaterials have beenwidely used in electrochemistry area, such as used as catalyst in electrocatalytic reaction andused as electrode material in capacitor. Based on the previously research, we fabricated somenovel porous carbon and its nanocomposite materials, and then researched theirelectrocatalytic application, the content was listed below:(1) We examined the electrocatalytic application of a novel mesoporous carbonnanofiber (M-CNF) that was synthesized using a self templating strategy, it employed as acarbon electrode material for detecting DA, AA and UA and exhibited significantly enhancedelectrocatalytic performance. Moreover, the superior electrocatalytic capability of the M-CNFwas confirmed by its simultaneous detection of DA, AA and UA at a physiological pH of7.4,where it demonstrated a wide linear range and high sensitivity. In addition, other biomoleculessuch as some purines were examined in the presence of the M-CNF, and its outstandingperformance verified that the M-CNF was a promising electrocatalyst. Next, by combiningthe advantages of unique nanostructure and large surface area of M-CNF combined with theelectrocatalytic ability of Au nanoparticles, M-CNF-Au was successfully prepared as ahydrazine catalyst. Low detection limit, wide linear range and short response time providedan opportunity for M-CNF-Au as a promising electrode material for the fabrication of anefficient hydrazine amperometric sensor. Moreover, this nanocomposite suggests greatpotential applications in the design and construction of M-CNF based materials forelectrocatalytic application.(2) PtxPdy/LMC nanocomposites were prepared. In application to electrochemistry,hydrogen peroxide and nitrite were employed as the probes to measure the electrochemicalperformance of PtxPdy/LMC. Comparison of hydrogen peroxide reduction and nitriteoxidation on PtxPdy/LMC/GCE indicated that the Pt1Pd1/LMC/GCE exhibited the highestactivity. The combination the high-efficiency catalysis and synergistic effect of Pt, Pd alloynanoparticles to electrocatalytic reaction and the unique structure of LMC matrix endows theenhanced electrochemical performance of Pt1Pd1/LMC/GCE. It is expected that thePt1Pd1/LMC/GCE is not only a sensitive sensor for hydrogen peroxide and nitrite in practicalapplication, but also can used as a high-performance electrocatalyst for other substances.Inspired by LMC, we reported a one step and green approach for the fabrication of N-LMCby using herring sperm DNA as carbon and nitrogen precursor. N-LMC/GCE was fabricated, and its electrocatalytic performance for the ORR was investigated. With high amounts ofpyridinic N and graphitic N, N-LMC-800exhibited higher electrocatalytic activity for theORR than LMC, which made it a very promising cathode catalyst for fuel cell application.(3) We successfully prepared OMC-S-X with different sulfur contents through varyingthe relative amounts of sucrose and benzyl disulfide in the preparation procedure. Theresulting OMC-S-3served as metal-free catalyst that showed outstanding electrocatalyticactivity, good stability and excellent resistance tocrossover effect for ORR. Moreover, theinfluence of different S-bonding configurations in OMC-S-X for ORR was researched whichproved that C-S-C played an important role in promoting the ORR activity.(4) PDA-HCS-Co with nanoporous hollow sphere morphology was prepared. AlthoughPDA-HCS alone had little catalytic activity for ORR, PDA-HCS-Co exhibited similar highcatalytic activity but superior stability and methanol tolerance compared to commercial Pt-Ccatalyst. This indicates combining the advantages of nitrogen and Co-N for ORR; thesynthesized PDA-HCS-Co is a promising non-precious metal ORR catalyst.(5) We demonstrated the rational design and fabrication of a novel P-GR using copperas an etching agent. In particular, the electrochemical behaviors of various electroactivecompounds were studied on P-GR/GCE, which exhibited more favorable electron transferkinetics than that on GR/GCE. The greatly enhanced electrochemical reactivity of theseprobes on P-GR/GCE is attributed to the unique porous structure, higher amounts of EDSsand more acidic groups of P-GR relative to GR. This research is of great significance not onlybecause it is an innovative strategy of preparing P-GR but also because it constructs a novelelectrochemical biosensing platform based on the freshly prepared P-GR, expand theapplication field of P-GR.

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