本文選題：水熱法　切入點(diǎn)：二硫化鉬　出處：《青島科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：近些年來,能源問題是全球都一直關(guān)注的重點(diǎn)問題,隨著對(duì)能源的需求越來急切,也就急需探索和研究新型綠色能源來解決這個(gè)問題。納米材料的出現(xiàn)和日漸成熟有望在能源問題上有很大的應(yīng)用,尤其是新型過渡金屬硫化物納米材料以及其復(fù)合材料,這些納米材料來源廣泛,價(jià)格便宜,對(duì)環(huán)境友好,而且具有高的比表面積以及好的化學(xué)穩(wěn)定性,在鋰離子二次電池和電化學(xué)催化析氫反應(yīng)中有廣泛的應(yīng)用。但是,過渡金屬硫化物本身導(dǎo)電性很差,鋰離子擴(kuò)散速率較低,析氫過電位較高,而且在鋰離子的嵌入-脫出過程中體積變化較大,導(dǎo)致其應(yīng)用在鋰離子電池上時(shí)倍率性能和循環(huán)性能較差;在作為電催化析氫反應(yīng)的催化劑時(shí),過電位又較高,能量損失嚴(yán)重,這些缺點(diǎn)都限制了它在實(shí)際生活中的應(yīng)用。為了克服以上缺陷,研究人員嘗試將過渡金屬硫化物制備成特殊的形貌或?qū)⑵渑c碳材料結(jié)合制成復(fù)合納米材料,特殊形貌的納米材料具有大的比表面積,因此擴(kuò)大了電解液和活性物質(zhì)的接觸面積;過渡金屬硫化物與碳材料復(fù)合,增加了材料的導(dǎo)電性,緩解了體積效應(yīng)。所以改進(jìn)后的過渡金屬硫化物擁有更好的電化學(xué)性能,在鋰離子電池和電化學(xué)催化析氫反應(yīng)中有更好的應(yīng)用。本論文主要研究了片狀的MoS_2-CoMo_2S_4/G、3D結(jié)構(gòu)的MoS_2-G、SnS_2-G和PB-MoS_2-G的制備及其電化學(xué)性能,包括儲(chǔ)鋰性能和電化學(xué)析氫性能。1)我們采用一步水熱法在石墨烯基體上原位生長(zhǎng)二維結(jié)構(gòu)的二硫化鉬納米片和CoMo_2S_4納米片,作為新型的電化學(xué)析氫反應(yīng)催化劑。由于石墨烯結(jié)構(gòu)的良好導(dǎo)電性和MoS_2和CoMo_2S_4之間的電化學(xué)協(xié)同作用和2D的結(jié)構(gòu)優(yōu)勢(shì),MoS_2-CoMo_2S_4/graphene復(fù)合催化劑顯示出很好的析氫性能,起始電位低至110mV,在η=300 mV時(shí),陰極電流密度高達(dá)85 mA cm-2,塔菲爾斜率為42 mV dec-1,第1000圈的催化曲線跟第1圈的比較,析氫效率并沒有衰減,顯示了良好的耐久性。2)此次工作將亞鐵氰化鉀,二硫化鉬和石墨烯通過一步水熱的方法,合成MoS_2-PB-GO復(fù)合材料。復(fù)合材料中具有獨(dú)特的PB立方體,與石墨烯緊密結(jié)合。合成的復(fù)合材料同時(shí)具有獨(dú)特的結(jié)構(gòu)和組成優(yōu)勢(shì),在電化學(xué)析氫反應(yīng)中顯示出優(yōu)異的催化性能。此種具有特殊3D結(jié)構(gòu)的復(fù)合催化劑顯示出低至160 mV的過電位,在過電壓為300 mV時(shí),對(duì)應(yīng)的電流密度達(dá)到60 mA cm-2,而且經(jīng)過測(cè)試,材料還具有較大的電化學(xué)活性表面積(ECSA),每個(gè)活性位點(diǎn)還具有較高的電催化活性,這對(duì)復(fù)合材料催化性能的提高都起到了很重要的促進(jìn)作用。3)利用水熱法合成了基于MoS_2-G混合納米片自組裝成的3D構(gòu)造,片層的MoS_2納米片和石墨烯基底緊密結(jié)合。特殊的3D架構(gòu)以及復(fù)合材料的組分選擇,有益于提高鋰離子電池和HER的電化學(xué)性能。在電流密度為200 m A g~(-1)時(shí),循環(huán)200圈后,容量仍然保持在904 mAh g~(-1),相比循環(huán)2圈后的容量910 mAh g~(-1),容量保持率為99%,說明其良好的循環(huán)性能。在1 Ag~(-1)和2 Ag~(-1)的高電流密度下循環(huán),依然保持706 mAh g~(-1)和581 mAh g~(-1)的高容量,當(dāng)電流密度再回到100mA g~(-1)時(shí),容量恢復(fù)至898 mAh g~(-1),顯示出好的結(jié)構(gòu)穩(wěn)定性和可逆性。在析氫反應(yīng)中,MoS_2-G顯示出低至110 mV的過電位,塔菲爾斜率為47 m V dec-1,而且在循環(huán)1000圈后,電化學(xué)析氫性能并沒有衰減,顯示出良好的循環(huán)穩(wěn)定性。4)通過水熱法合成由2D SnS_2納米片和石墨烯復(fù)合組成的3D結(jié)構(gòu),由于SnS_2-G的結(jié)構(gòu)優(yōu)勢(shì),顯示出良好的鋰離子存儲(chǔ)性能。2D的片狀結(jié)構(gòu)提供了大的比表面積和結(jié)構(gòu)穩(wěn)定性,同時(shí)也緩解了體積效應(yīng)。SnS_2和石墨烯的緊密連接保證了快速的電子交換,所以該復(fù)合材料在作為負(fù)極材料時(shí),容量高至933 mAh g~(-1),在500 mA g~(-1)的電流密度下循環(huán)200圈后,容量依然保持在826 mAh g~(-1),顯示出良好的循環(huán)穩(wěn)定性,在8 A g~(-1)的高電流密度下,容量為498 mAh g~(-1),表現(xiàn)出杰出的倍率性能。
[Abstract]:In recent years, the energy problem is the key problem in the world have been concerned, with the growing demand for energy is urgent, urgent need to explore and study new green energy to solve this problem. The emergence of nano materials and is expected to become more mature in terms of energy has great applications, especially the new Transition Metal Sulfide Nanomaterials and their composites these nano materials, wide material source, cheap, environmentally friendly, and has a high surface area and good chemical stability, is widely used in the reaction of lithium ion secondary battery two and the electrochemical hydrogen evolution. However, the conductivity of transition metal sulfides itself is very poor, the lithium ion diffusion is low. Hydrogen overpotential is higher, and the volume changes in lithium ion - intercalation process is large, when the application rate performance and cycle performance in lithium ion battery; In the catalyst as the electrocatalytic reaction when the potential is higher, the energy loss is serious, these disadvantages limit its application in real life. In order to overcome the above defects, researchers try to transition metal sulfide prepared into special shape or combine it with carbon materials made of composite nano materials, nano materials with special morphology with large surface area, thus expanding the contact area of the electrolyte and active material; composite transition metal sulfide and carbon materials, increasing the conductivity of the material, alleviate the volume effect. So the electrochemical properties of transition metal sulfides into the better, has a better application in lithium ion battery and the electrochemical hydrogen evolution reaction. This paper mainly studies the flake like MoS_2-CoMo_2S_4/G, 3D MoS_2-G and PB-MoS_2-G SnS_2-G structure, the preparation and electrochemical properties, including storage The properties of lithium and the electrochemical hydrogen evolution properties of molybdenum disulfide and.1) CoMo_2S_4 nanosheets we used one-step hydrothermal method in situ growth in two-dimensional structure of graphene substrate, as the electrochemical hydrogen evolution reaction catalyst model. Due to the structural advantages of electrochemical between graphene structure and good conductivity and MoS_2 and CoMo_2S_4 and 2D synergistic effect the MoS_2-CoMo_2S_4/graphene composite catalyst showed the hydrogen evolution of good performance, low initial potential to 110mV in =300 mV, ETA, the cathodic current density up to 85 mA cm-2, Tafel slope of 42 mV dec-1, compared with 1000th laps of the catalytic curve with first rings, the hydrogen evolution efficiency and no attenuation, shows a good the durability of.2) the work of potassium ferrocyanide, MoS2 and graphene by one-step hydrothermal method, synthesis of MoS_2-PB-GO composite materials. The composite has a unique PB cube, and stone Combination of graphene. The synthesis of composite materials with special structure and composition, showed excellent catalytic performance in the electrochemical hydrogen evolution reaction. The composite catalyst has a special 3D structure shows the potential is too low to 160 mV, the voltage is 300 mV, the current density should reach 60 mA cm-2, but after testing, material also has a larger electrochemical active surface area (ECSA), the electrocatalytic activity of each active site also has high, which increases the catalytic properties of the composite materials play a very important role in promoting.3 3D) to construct MoS_2-G mixed nano film based on self assembly was prepared by the hydrothermal method, combined with lamellar MoS_2 nanosheets and graphene substrate. The special 3D architecture and composite components, is beneficial to improve the electrochemical performance of lithium ion battery and HER. At a current density of 200 m A G ~(-1)鏃，

本文編號(hào)：1576755