本文選題：電催化析氧反應(yīng)　切入點(diǎn)：硅酸鎳鈷　出處：《西華師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：化石燃料的日益短缺以及因其大量使用所帶來(lái)的環(huán)境問(wèn)題已經(jīng)成為人類社會(huì)可持續(xù)發(fā)展的障礙。顯然,有必要發(fā)掘可持續(xù)、清潔、高效的能源來(lái)取代化石燃料。氫氣是一種理想的清潔能源,且電分解水制氫是未來(lái)獲得高純度氫分子的一種重要途徑。析氧反應(yīng)由于是多電子過(guò)程,具有緩慢的動(dòng)力學(xué)和相對(duì)高的過(guò)電勢(shì),因此成為電解水的瓶頸問(wèn)題。貴金屬氧化物的催化效率通�？梢赃_(dá)到要求,但高昂的價(jià)格限制了其實(shí)際應(yīng)用。因此,開(kāi)發(fā)價(jià)格低廉的非貴金屬催化劑意義重大。層狀過(guò)渡金屬硅酸鹽由于其獨(dú)特的晶體結(jié)構(gòu),以及資源豐富、制備簡(jiǎn)單等優(yōu)點(diǎn)已廣泛應(yīng)用于光學(xué)材料、催化、氣體傳感器和水處理劑等領(lǐng)域。本論文利用不同改性手段,提高了過(guò)渡金屬硅酸鹽電催化分解水的能力。主要研究?jī)?nèi)容如下:1、首先,用一定濃度的硝酸對(duì)多壁碳納米管(記作MWCNTs)進(jìn)行純化處理;然后,以MWCNTs為模板,利用溶膠-凝膠法合成SiO_2并均勻負(fù)載于MWCNTs表面,得到MWCNTs@SiO_2;最后采用簡(jiǎn)單的水熱反應(yīng),在180℃下反應(yīng)24 h得到負(fù)載于多壁碳納米管的堿式硅酸鎳鈷,即MWCNTs@(Ni,Co)_3Si_2O_5(OH)_4(記作MWCNTs@NCS)。通過(guò)掃描電子顯微鏡(SEM)、透射電子顯微鏡(TEM)、X射線衍射(XRD)、X射線光電子能譜(XPS)等手段對(duì)其形貌、物相、組成進(jìn)行分析。在0.1 M KOH電解質(zhì)中對(duì)電極材料進(jìn)行析氧性能測(cè)試,MWCNTs@NCS-2在10 mA·cm-2時(shí)的過(guò)電勢(shì)約為440 mV,且塔菲爾斜率為96 mV/dec。MWCNTs@NCS優(yōu)異的析氧性能緣于層狀過(guò)渡金屬硅酸鹽與碳納米管之間的協(xié)同效應(yīng)。2、利用溶膠-凝膠法合成SiO_2并采用簡(jiǎn)單的水熱反應(yīng)得到由納米片組成的中空微球(Ni,Co)_3Si_2O_5(OH)_4前驅(qū)體(記作NCS),再通過(guò)低溫磷修飾的方法最終得到(Ni,Co)_3Si_2O_5(OH)_4-P(記作NCS-P)。改變不同的磷修飾溫度以優(yōu)化條件,從而探索出堿式硅酸鎳鈷適合磷修飾的最佳溫度。通過(guò)SEM、TEM、XRD、XPS等手段對(duì)其形貌、物相、組成進(jìn)行分析。在1 M KOH電解質(zhì)中測(cè)試析氧性能,NCS-P-275在10 mA·cm-2時(shí)的過(guò)電勢(shì)約為394 mV,且塔菲爾斜率為67 mV/dec。利用磷修飾來(lái)提高物質(zhì)的電化學(xué)活性位點(diǎn),從而從另外一個(gè)角度來(lái)提高過(guò)渡金屬硅酸鹽的電催化析氧性能。3、因?yàn)榘l(fā)現(xiàn)純粹的堿式硅酸鎳鈷經(jīng)過(guò)磷修飾處理后能夠大大提高電催化析氧性能,我們將在第一個(gè)工作的基礎(chǔ)上進(jìn)行磷修飾,以探索性能更好的電極材料。首先,利用上述相似方法先制備負(fù)載于多壁碳納米管上的層狀堿式硅酸鎳鈷MWCNTs@NCS;然后,采用磷修飾的方式最終得到MWCNTs@NCS-P-400�？刂茖�(shí)驗(yàn)不加次磷酸鈉,其它條件(如熱處理溫度和時(shí)間)保持不變。通過(guò)SEM、TEM、XRD、XPS等手段對(duì)其形貌、物相、組成進(jìn)行分析。在1 M KOH電解質(zhì)中對(duì)電極材料進(jìn)行析氧性能測(cè)試,MWCNTs@NCS-P-400在10 mA·cm-2時(shí)的過(guò)電勢(shì)約為328 mV,且塔菲爾斜率為49 mV/dec。利用層狀過(guò)渡金屬硅酸鹽與碳納米管之間的協(xié)同效應(yīng),以及磷修飾提高物質(zhì)的電化學(xué)活性位點(diǎn),從而更進(jìn)一步提高電催化析氧性能。
[Abstract]:The shortage of fossil fuels and because of the extensive use of the environmental problem has become the obstacle to the sustainable development of human society. It is necessary to explore, sustainable, clean, efficient energy to replace fossil fuels. Hydrogen is an ideal clean energy, electricity and water solution of hydrogen production is an important way to obtain high purity hydrogen the future of molecular oxygen evolution reaction. Because of the multi electronic process, with slow kinetics and relatively high overpotential, therefore becomes a bottleneck problem in water electrolysis. The catalytic efficiency of noble metal oxides can generally meet the requirements, but the high cost limits its practical application. Therefore, the significance of the development of non noble metal catalysts with low price layered transition metal silicate material. Because of its unique crystal structure, and is rich in resources, advantages of simple preparation, has been widely used in optical materials, catalysis, gas sensing Device and water treatment agent. Different modification methods used in this paper, to improve the ability of transition metal silicate electro catalytic decomposition of water. The main contents are as follows: 1, first of all, the multi walled carbon nanotubes with nitrate concentration (MWCNTs) was purified; then, by using MWCNTs as template. Sol gel synthesis of SiO_2 and uniform load on the surface of MWCNTs MWCNTs@SiO_2; finally, using a simple hydrothermal reaction, 24 h basic silicate nickel cobalt supported on multi walled carbon nanotubes reaction under 180 degrees, namely MWCNTs@ (Ni, Co) _3Si_2O_5 (OH) _4 (MWCNTs@NCS) by scanning. Electron microscopy (SEM), transmission electron microscopy (TEM), X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and other means on the morphology, phase composition analysis. The oxygen evolution performance test of electrode materials in 0.1 M KOH electrolyte, MWCNTs@NCS-2 in the 10 mA - cm-2 When the potential is about 440 mV, and the Tafel slope of synergy between.2 96 mV/dec.MWCNTs@NCS with excellent performance for oxygen evolution due to layered transition metal silicate and carbon nanotubes, prepared by sol-gel method and hydrothermal reaction using SiO_2 simple hollow microspheres composed of nanosheets (Ni, Co) by _3Si_2O_5 (OH _4) precursor (NCS), to get through the method of low temperature phosphate modified (Ni, Co) _3Si_2O_5 (OH) _4-P (NCS-P). The temperature change of different phosphorus modified to optimize the conditions, in order to explore the optimum temperature of basic silicate nickel cobalt suitable phosphorus modified by SEM, TEM XRD, XPS, and other means on the morphology, phase composition analysis. The test of oxygen evolution properties in 1 M KOH electrolyte, NCS-P-275 at 10 mA over potential cm-2 is about 394 mV, and Tafel mV/dec. with a slope of 67 P modified electrochemical active sites to high material, And from another point of view to improve the electrocatalytic oxygen evolution properties of.3 transition metal silicates, because pure nickel cobalt silicate hydroxide after phosphorus after modification can greatly improve the electrocatalytic performance for oxygen evolution, we will be based on the first phosphorus modified on the electrode materials in exploring better first. First, the preparation of supported on multiwalled carbon nanotubes of layered silicate nickel cobalt hydroxide MWCNTs@NCS by using the similar method; then, using phosphorus modified MWCNTs@NCS-P-400. control experiment is obtained without the addition of sodium hypophosphite, other conditions (such as heat treatment temperature and time) remain unchanged. Through SEM, TEM, XRD, XPS etc. the morphology, phase composition analysis. To test the performance of the oxygen evolution electrode in 1 M KOH electrolyte, MWCNTs@NCS-P-400 at 10 mA over potential cm-2 is about 328 mV, and the Tafel slope is 49 mV/d Ec. utilizes the synergistic effect between layered transition metal silicates and carbon nanotubes, as well as phosphorus modification to improve the electrochemical active sites of the material, thus further improving the performance of electro catalytic oxygen evolution.

【學(xué)位授予單位】：西華師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36;TQ116.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 謝丹丹;曲曉飛;杜芳林;;形貌和尺寸可控的二氧化硅/硅酸鎳錳空心微球的制備[J];材料導(dǎo)報(bào);2014年10期

，

本文編號(hào)：1627664