本文選題：二維納米材料 + 二氧化鈦　； 參考：《南京大學(xué)》2017年博士論文

【摘要】：自2004年石墨烯的發(fā)現(xiàn)以來(lái),具有原子級(jí)厚度和高度各向異性的超薄二維納米材料引起了人們廣泛關(guān)注。這類(lèi)獨(dú)特維度尺寸受限結(jié)構(gòu)具有的量子限域效應(yīng)和表面效應(yīng)使其表現(xiàn)出與普通體相材料不同的物理化學(xué)性質(zhì),在催化、電化學(xué)、吸附、分離、電學(xué)、光學(xué)、磁學(xué)等諸多領(lǐng)域具有巨大的應(yīng)用潛力,引發(fā)了全球范圍內(nèi)的研究熱潮。氧化鈦納米片在環(huán)境、儲(chǔ)能、催化等諸多方面具有重要的的應(yīng)用前景,對(duì)其結(jié)構(gòu)調(diào)控、組裝及性能研究尚少見(jiàn)報(bào)道,大量制備厚度1nm左右的高質(zhì)量、結(jié)構(gòu)明確的氧化鈦超薄納米片仍是一個(gè)挑戰(zhàn)。本文主要以超薄TiO2納米片材料為研究對(duì)象,通過(guò)液相剝離的方法制備了單層鈦酸鹽納米片(TiONS),并進(jìn)一步研究其轉(zhuǎn)晶、組裝、復(fù)合結(jié)構(gòu)調(diào)控以及其光催化、電化學(xué)儲(chǔ)能等性能,取得了如下研究成果:1.發(fā)展了超薄納米片負(fù)載納米顆粒避免其堆疊復(fù)合的方法。通過(guò)液相剝離的方法成功制備了鈦酸鹽納米片、α-ZrP納米片、氧化石墨烯、鎂鋁水滑石納米片等溶膠。(1)以單層鈦酸鹽納米片(TiONS)為載體,于液相中負(fù)載Pd,得到濕狀Pd/TiONS,將其直接用于液相苯酚選擇性加氫制備環(huán)已酮反應(yīng)。載體TiONS不發(fā)生過(guò)度堆疊復(fù)合,納米片厚約0.9nm,Pd顆粒約1.9nm,具有高比表面積,該催化劑表現(xiàn)出較干燥Pd/TiONS更高的活性;(2)將液相剝離的超薄納米片與14nm大小的SiO2納米顆粒復(fù)合,通過(guò)SiO2納米顆粒的支撐保護(hù),有效地避免納米片在進(jìn)一步的干燥及熱處理中發(fā)生堆疊燒結(jié),得到了 SiO2納米顆粒支撐超薄納米片的復(fù)合材料。2.超薄二氧化鈦納米片的制備及結(jié)構(gòu)與性能研究。在前一工作的基礎(chǔ)上,通過(guò)精細(xì)的調(diào)變,優(yōu)化了有效保持鈦酸鹽納米片超薄結(jié)構(gòu)的最低SiO2用量。進(jìn)一步將鈦酸鹽納米片500℃熱處理使其由纖鐵礦型結(jié)構(gòu)鈦酸鹽轉(zhuǎn)變?yōu)殇J鈦礦結(jié)構(gòu)二氧化鈦,氧化鈦納米片厚約0.6nm,主要暴露高能(116)晶面,且?guī)吨递^塊體銳鈦礦增大了約0.4 eV,在催化紫外光降解羅丹明B反應(yīng)中表現(xiàn)出優(yōu)異的性能。在獲得的銳鈦礦納米片-Si02納米顆粒復(fù)合材料的基礎(chǔ)上,通過(guò)NaOH溶液除去SiO2,進(jìn)一步的酸化脫Na+再煅燒,獲得比表面積達(dá)200 m2 g~(-1)自支撐的銳鈦礦二氧化鈦納米片。3.TiO2@carbon復(fù)合材料的控制合成與鋰離子電池儲(chǔ)能應(yīng)用。我們將液相剝離的TiONS與有機(jī)碳源作用并原位碳化控制合成了炭層緊密包覆的TiO2@carbon核殼型納米片,TiO2納米片的厚度約1.1nm,炭層的厚度約為2.2 nm,超薄的氧化鈦納米片縮短了鋰離子的運(yùn)動(dòng)路程,有利于鋰離子的快速嵌入/脫出,包覆的炭層有效地提高了材料整體的導(dǎo)電性,同時(shí)炭的引入使其本身的容量貢獻(xiàn)極大地提高了材料整體的容量,并進(jìn)一步提高了二維結(jié)構(gòu)的穩(wěn)定性。將該材料用作鋰離子電池負(fù)極材料,在0.23 Ag~(-1)的電流密度下循環(huán)300次后,可逆容量高達(dá)549 mAh g~(-1),在4.6 A g~(-1)的高倍率下循環(huán)2000次后,可逆容量仍高達(dá)385 mAh g~(-1)。
[Abstract]:Since the discovery of graphene in 2004, ultrathin two-dimensional nanomaterials with atomic thickness and high anisotropy have attracted much attention.The quantum confinement and surface effects of this unique dimensional size limited structure exhibit physical and chemical properties different from those of ordinary bulk materials in catalysis, electrochemistry, adsorption, separation, electricity, optics,Many fields, such as magnetism, have great application potential, which has triggered a worldwide research boom.Titanium oxide nanocrystals have important applications in environment, energy storage, catalysis and so on. There are few reports on the structure control, assembly and performance of titanium oxide nanocrystals, and a large amount of high quality 1nm with thickness is prepared.Clearly structured titanium oxide nanocrystals remain a challenge.In this paper, ultrathin TiO2 nanocrystals were prepared by liquid phase stripping method, and their properties of transprystallization, assembly, composite structure control, photocatalytic and electrochemical energy storage were studied.The following research results have been achieved: 1.The method of loading nanocrystalline particles to avoid stacking and recombination was developed.TIO _ 3 nanocrystals, 偽 -ZrP, graphene oxide and magnesia-aluminum hydrotalcite nanoparticles were successfully prepared by liquid-phase stripping method. The monolayer titanate nanoparticles (TiONSs) were used as the support.The wet PD / TiONSs were obtained by loading PD in liquid phase, which was directly used for selective hydrogenation of phenol to cyclohexanone in liquid phase.There was no excessive stacking of the supported TiONS, and the thickness of the nanoparticles was about 0.9 nm, with a high specific surface area. The catalyst showed a higher activity than dry Pd/TiONS.Through the support and protection of SiO2 nanoparticles, the stacking sintering of nanocrystalline particles in further drying and heat treatment was avoided, and the composite material. 2. 2 of SiO2 nanoparticles supported ultrathin nanocrystals was obtained.Preparation, structure and Properties of ultrathin Titanium dioxide nanoparticles.On the basis of the previous work, the minimum amount of SiO2 was optimized to keep the ultrathin structure of titanate nanocrystals by fine-tuning.The titanate nanocrystalline was further heat treated at 500 鈩，

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