本文選題：析氫反應(yīng) + 枝狀NiCu納米晶��； 參考：《合肥工業(yè)大學(xué)》2015年碩士論文

【摘要】：氫能是一種理想的能源載體,具有無(wú)污染、能量密度高、可實(shí)現(xiàn)各類能源的能量轉(zhuǎn)移等優(yōu)點(diǎn)。電解水可制得高純度氫氣,但因能源消耗大,大規(guī)模的實(shí)際生產(chǎn)應(yīng)用受到了很大限制,需要通過(guò)開發(fā)高催化活性的電極材料來(lái)降低析氫過(guò)電勢(shì)。本論文中,在不同基底電極表面分別修飾鎳銅納米合金和2-氨基-5-巰基-1,3,4-噻二唑(AMT),研究?jī)煞N材料對(duì)析氫反應(yīng)的電催化活性。通過(guò)恒電流法在銅基底表面沉積不同原子比的NiCu合金,并測(cè)試其在硫酸介質(zhì)中的催化析氫性能。采用場(chǎng)發(fā)射掃描電子顯微鏡(FE-SEM)和能譜(EDX)技術(shù)對(duì)合金層的表面形貌和組成進(jìn)行分析表征,結(jié)果表明,所沉積的NiCu合金組成與采用的電流密度直接相關(guān),當(dāng)電流密度為50 mA cm-2時(shí),NiCu原子比為1:1,呈枝晶狀的納米珍珠鏈緊密排列。利用線性極化法對(duì)析氫電催化活性進(jìn)行評(píng)價(jià),NiCu原子比為1:1時(shí)活性最強(qiáng),交換電流密度比Cu電極提高2836倍,析氫超電勢(shì)(η50)降低265 mV;比純Ni的Cu基電極的交換電流密度提高8.5倍,析氫超電勢(shì)(η50)降低135 mV。由交流阻抗圖譜和計(jì)時(shí)電勢(shì)數(shù)據(jù)可知,NiCu納米合金能顯著降低析氫反應(yīng)的電荷傳遞電阻,有利于提高活性氫從活性位點(diǎn)的脫附能力。綜合分析可知,枝狀NiCu納米晶是具有優(yōu)越電催化活性的非貴金屬析氫催化劑。采用多圈循環(huán)掃描伏安法在玻碳電極表面電氧化AMT形成導(dǎo)電聚合物PAMT,并測(cè)試其在酸性電解液中的催化析氫性能。對(duì)制備的電極材料進(jìn)行FE-SEM和XPS表征,PAMT薄膜表面均勻致密,表面呈褶皺的短絲狀形貌(長(zhǎng)度小于100 nm)。經(jīng)Tafel曲線分析可知,PAMT催化劑使電極開路電勢(shì)正移約313mV,析氫活化能顯著降低；由交流阻抗圖譜和計(jì)時(shí)電勢(shì)法可以看出,PAMT膜不僅能降低析氫反應(yīng)的電荷傳遞電阻,還能有效加快氫原子從電極活性位點(diǎn)的脫除過(guò)程。在PAMT薄膜上的析氫活性位可用—N=來(lái)表示,其成對(duì)出現(xiàn)可滿足H-H結(jié)合所需。上述分析表明,富含氮、硫原子的導(dǎo)電聚合物作為析氫電催化劑具有廣闊的發(fā)展前景。不同的基底材料對(duì)電催化體系的影響作用不同。為考察不同碳基底電極對(duì)修飾PAMT導(dǎo)電聚合物薄膜的析氫性能影響,同樣在sCPE電極表面電聚合PAMT薄膜。對(duì)比PAMT/sCPE和PAMT/GCE電極在酸性介質(zhì)下的催化析氫活性,經(jīng)過(guò)比較,在不同基底電極上修飾PAMT薄膜的最佳聚合圈數(shù)存在差異；在碳糊電極的最佳聚合圈數(shù)為100,而玻碳電極的聚合圈數(shù)在60時(shí)達(dá)到最佳析氫活性,且PAMT/sCPE薄膜電極的交換電流密度是sCPE電極的647倍,活化能提高65%1而PAMT/GCE電極是GCE電極的533倍,活化能提高48%。從上述實(shí)驗(yàn)數(shù)據(jù)分析可知,sCPE基底電極的析氫催化活性在一定程度上要優(yōu)于GCE電極。
[Abstract]:Hydrogen energy is an ideal energy carrier, which has the advantages of no pollution, high energy density and can realize energy transfer of all kinds of energy. Electrolytic water can produce high purity hydrogen, but because of the large energy consumption, the application of large-scale practical production is greatly limited, it is necessary to develop high catalytic activity electrode materials to reduce the potential of hydrogen evolution. In this paper, the electrocatalytic activity of nickel copper nanoalloy and 2-amino-5-mercaptol 3-thiadiazole-4-thiadiazolium on the surface of different substrate electrodes for hydrogen evolution was studied. NiCu alloys with different atomic ratios were deposited on the surface of copper substrate by constant current method and their catalytic hydrogen evolution properties in sulfuric acid medium were tested. The surface morphology and composition of the alloy layer were characterized by FE-SEM and EDX techniques. The results show that the composition of the deposited NiCu alloy is directly related to the current density. When the current density is 50 Ma cm-2, the atomic ratio of Ni Cu is 1: 1, and the nanocrystalline pearl chains are arranged tightly. The electrocatalytic activity of hydrogen evolution was evaluated by linear polarization method. The activity of NiCu atom was strongest at 1:1, the exchange current density was 2836 times higher than that of Cu electrode, the superpotential of hydrogen evolution (畏 50) was decreased by 265 MV, and the exchange current density of Ni based electrode was 8.5 times higher than that of pure Ni based electrode. The superpotential of hydrogen evolution (畏 50) is reduced by 135 MV. The electrochemical impedance spectra and chronopotentiometry data show that NiCu nanocrystalline alloy can significantly reduce the charge transfer resistance of hydrogen evolution reaction and improve the desorption ability of active hydrogen from the active site. Comprehensive analysis shows that dendritic NiCu nanocrystals are non-noble metal hydrogen evolution catalysts with superior electrocatalytic activity. AMT was electrooxidized on the surface of glassy carbon electrode by multi-loop cyclic scanning voltammetry to form a conductive polymer, PAMT.The catalytic hydrogen evolution of PAMTs in acidic electrolyte was tested. The prepared electrode materials were characterized by FE-SEM and XPS. The surface of the films was uniform and compact, and the surface of the films was pleated with short filaments (length less than 100nm). According to the analysis of Tafel curves, the open circuit potential of the electrode was positively shifted to about 313mV, and the activation energy of hydrogen evolution was significantly decreased, and the electrochemical impedance diagram and chronopotentiometry showed that the PAMT film could not only reduce the charge transfer resistance of hydrogen evolution reaction, but also decrease the charge transfer resistance of hydrogen evolution reaction. It can also accelerate the removal of hydrogen atoms from the active sites of the electrode. The active sites of hydrogen evolution on PAMT thin films can be represented by -N =, and the pair can meet the needs of H-H binding. The results show that the electrically conductive polymers rich in nitrogen and sulfur atoms are promising as electrocatalysts for hydrogen evolution. The effect of different substrate materials on the electrocatalytic system is different. In order to investigate the effect of different carbon substrate electrodes on the hydrogen evolution properties of modified PAMT conductive polymer films, PAMT films were also electropolymerized on the surface of sCPE electrodes. By comparing the catalytic hydrogen evolution activity of PAMT/sCPE and PAMT/GCE electrodes in acid medium, the optimum number of polymerization cycles for modified PAMT films on different substrate electrodes is different. The optimum polymerization cycle number of carbon paste electrode is 100, while the polymerization cycle number of glassy carbon electrode is 60. The exchange current density of PAMT/sCPE thin film electrode is 647 times that of sCPE electrode, and the activation energy of PAMT/GCE electrode is 533 times that of GCE electrode. Activation energy increases by 48. According to the above experimental data, the catalytic activity of the substrate electrode for hydrogen evolution is better than that of the GCE electrode to some extent.
【學(xué)位授予單位】：合肥工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ116.2;O643.36

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本文編號(hào)：1803318