錢文靜,袁超,郭江娜,嚴鋒(蘇州大學材料與化學化工學部,江蘇蘇州 215123)
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聚離子液體功能材料研究進展*
錢文靜,袁超,郭江娜,嚴鋒
(蘇州大學材料與化學化工學部,江蘇蘇州 215123)
離子液體(Ionic Liquids,ILs)是由正、負離子組成的,在室溫或室溫附近呈現(xiàn)液體狀態(tài)的有機熔融鹽[1~3]。離子液體具有蒸汽壓低、電導率高、電化學窗口寬、熱穩(wěn)定性好等獨特的物理化學性質(zhì),已經(jīng)引起學術(shù)界和工業(yè)界的興趣與廣泛關(guān)注[4~9]。
聚離子液體(Poly(ionic liquid)s)是指由離子液體單體聚合生成的,在重復單元上具有陰、陽離子基團的一類離子液體聚合物,兼具離子液體和聚合物的優(yōu)良性能[10,11]。按照化學結(jié)構(gòu),聚離子液體可分為以下幾類(圖1):(1)聚陽離子型離子液體,即陽離子以共價鍵與聚合物主鏈相連;(2)聚陰離子型離子液體,即陰離子以共價鍵與聚合物主鏈相連;(3)兩性型聚離子液體,即陽離子和陰離子都通過共價鍵與聚合物主鏈相連[5]。由于聚離子液體兼具離子液體與聚合物的優(yōu)點,并且克服了離子液體的流動性,因而近年來成為高分子科學領(lǐng)域研究的熱點之一[12~15]。
聚離子液體的合成可以通過自由基引發(fā)聚合離子液體單體的方法實現(xiàn)。與離子液體性質(zhì)類似,人們可通過對聚離子液體的陰離子或陽離子的設(shè)計與組合,對聚離子液體進行分子結(jié)構(gòu)設(shè)計,合成多種不同結(jié)構(gòu)和功能的聚離子液體。目前利用咪唑鹽陽離子單體聚合制備聚離子液體的研究較多。利用陰離子交換對其功能化,可以在聚合前(單體)也可以在聚合后(聚合物)進行(圖2)。例如,Mecerreyes 等[1]制備并聚合了1-乙烯基-3-丁基咪唑氯化物和溴化物,并通過與(CF3SO2)2N-,等離子交換,調(diào)節(jié)聚合物的親疏水性。Texter 等利用微乳液聚合制備了聚離子液體凝膠。通過陰離子交換,制備了具有溶劑響應(yīng)性多孔聚合物材料(凝膠)[16]。
近年來,可控活性原子轉(zhuǎn)移自由基聚合(ATRP)和可逆加成-斷裂鏈轉(zhuǎn)移(RAFT)聚合、開環(huán)易位聚合(ROMP)、原位聚合、環(huán)化聚合、脫氫偶聯(lián)聚合等現(xiàn)代聚合方法也被初步引入用于合成聚離子液體[10,13,17~19]。
與非離子型聚合物相比,聚離子液體通常具有優(yōu)異的離子導電性、化學穩(wěn)定性、不易燃燒等特性。由于陽(陰)離子基團被“固定”在聚合物主鏈上,較之于離子液體,玻璃化轉(zhuǎn)變溫度隨之升高,離子流動性相應(yīng)降低,導致其粘度增大、電導率下降[13]。例如,離子液體的電導率通常在1×10-2S·cm-1左右,而聚離子液體的電導率往往低于1×10-6S·cm-1[20]。增加聚離子液體電導率的方法主要有兩種:(1)增加載體離子的濃度;(2)改變電解液的結(jié)構(gòu)來增加離子流動性[21]。一般說來,聚陽離子型離子液體的離子導電性低于聚陰離子型離子液體[22]。
聚離子液體這些特性使得其在(準)固態(tài)電解質(zhì)、燃料電池聚電解質(zhì)膜、刺激響應(yīng)材料、碳材料、電化學和催化等領(lǐng)域得到初步應(yīng)用,并展示了廣泛的應(yīng)用前景。
3.1(準)固態(tài)電解質(zhì)材料
由于聚合物可以在液體電解質(zhì)中形成三維網(wǎng)絡(luò)結(jié)構(gòu),使液體電解質(zhì)在凝膠網(wǎng)絡(luò)中進行固化,從而失去宏觀上的流動性。因此,較之于液態(tài)電解質(zhì),基于(準)固態(tài)電解質(zhì)的電化學器件具有難泄漏、安全性好的優(yōu)勢,更接近實際應(yīng)用。另外,聚合物(準)固態(tài)電解質(zhì)可以配合電極材料制備成任意的形狀,符合外觀多樣性設(shè)計的需要,有利于電化學器件向小型化、超薄型化、柔性化方向發(fā)展。2003年,Ohno等[23]合成了聚離子液體電解質(zhì)材料,研究了咪唑陽離子的位置,空間結(jié)構(gòu)和陰離子種類對其電導率的影響,從而使得聚離子液體(準)固態(tài)電解質(zhì)的研究引起人們的關(guān)注。聚離子液體型的(準)固態(tài)電解質(zhì)由于兼具聚合物的機械性能與可加工性,以及電導率高的優(yōu)勢,成為制備(準)固態(tài)電解質(zhì)的理想材料。
嚴鋒課題組制備了完全不含傳統(tǒng)有機溶劑的離子液體/聚離子液體準固態(tài)電解質(zhì)[24],電池光電轉(zhuǎn)換效率達到 4.4%,并呈現(xiàn)出優(yōu)良的電池穩(wěn)定性。將離子液體表面修飾的TiO2納米粒子引入離子液體/聚離子液體準固態(tài)電解質(zhì)中,電池光電轉(zhuǎn)換效率可以被進一步提升到5.26%。進一步的工作又設(shè)計合成了雙咪唑鹽陽離子聚離子液體和單咪唑鹽陽離子聚離子液體(圖3),制備了高效且不含有機溶劑的凝膠電解質(zhì)。對電解質(zhì)的電導率和I3-/I-擴散系數(shù)進行了測定,雙咪唑鹽陽離子聚離子液體比單咪唑陽離子液體的電導率和擴散系數(shù)要高,接近于離子液體液態(tài)電解質(zhì)。另外,咪唑環(huán)陽離子上π-π結(jié)構(gòu)在電池中更有利于電荷的傳輸。雙咪唑鹽陽離子聚離子液體可以在液態(tài)離子液體中形成一種聚離子液體納米通道,有利于I3-/I-在電解質(zhì)中擴散移動,提高DSSC的性能[25]。
3.2燃料電池堿性陰離子交換膜
堿性燃料電池由于可以使用Ag、Ni等非貴金屬催化劑而得到越來越多的關(guān)注。然而,目前應(yīng)用較多的基于季銨鹽對陰離子交換聚合物膜存在耐堿穩(wěn)定性差的缺陷。因此,合成具有高電導率及優(yōu)異耐堿穩(wěn)定性的新型陰離子交換聚合物膜,是燃料電池工業(yè)化應(yīng)用必須解決的一個難題,也在近年來得到人們越來越多的關(guān)注。
將咪唑鹽離子液體單體與丙烯腈、苯乙烯通過光交聯(lián)聚合的方法可以制備基于咪唑鹽離子液體的堿性陰離子交換聚合物膜[26]。該陰離子交換聚合物膜顯示良好的電導率,并且交聯(lián)劑的引入提高了堿性陰離子交換膜的機械性能。進一步的工作合成了基于雙咪唑鹽離子液體的堿性陰離子交換聚合物膜當離子液體單體含量為40 wt% 時,膜的電導率能夠達到10-2S/cm(90℃下),在1 mol/L KOH 溶液中(6℃)浸泡30 d后,其電導率沒有明顯下降,顯示了良好的耐堿穩(wěn)定性[27]。然而,咪唑鹽陽離子上的取代基團對其耐堿性影響很大。在對一系列 C2-位上含有取代基團咪唑鹽單體及其均聚物(圖4)的耐堿性研究時,發(fā)現(xiàn)σ-π 超共軛效應(yīng)對其耐堿性的影響最為明顯[28]。進一步的研究工作合成了一系列N3-位含有不同取代基的咪唑鹽和季銨鹽聚合物并測試了其耐堿性,結(jié)果表明異丙基取代的咪唑鹽陽離子比季銨鹽具有更優(yōu)異的耐堿穩(wěn)定性[29]。
3.3刺激響應(yīng)材料
刺激響應(yīng)性高分子材料是智能材料中的一種,它會在外界環(huán)境因素如溫度、pH、光、溶劑等刺激下,產(chǎn)生諸如相態(tài)、形狀、表面能、反應(yīng)速率、滲透速率或識別等性能物理或化學性質(zhì)的變化。有些材料可同時對兩種或兩種以上的刺激做出響應(yīng)。刺激響應(yīng)性高分子材料在生物醫(yī)學、藥物控制釋放、基因載體、納米粒子以及納米反應(yīng)器等眾多領(lǐng)域具有廣闊的應(yīng)用前景。
3.3.1溫度響應(yīng)性材料
雙親性聚離子液體通過自組裝成形態(tài)各異的聚集體(凝膠、膠束、囊泡等),從而制備溫度響應(yīng)性材料。Yuan等[17]將N-異丙基丙烯酰胺通過ATRP方法成功接枝到聚離子液體納米粒子表面,得到了溫度響應(yīng)和離子強度響應(yīng)的粒子。在高離子強度溶液中,該NP-g-PNIPAM粒子具有較高的膠束穩(wěn)定性。Xiong等[30]進一步合成了基于聯(lián)咪唑離子液體的納米凝膠(圖5),該納米粒子在甲醇中具有溫敏性,在改變溫度的條件下可以實現(xiàn)納米凝膠和宏觀凝膠間的可逆相轉(zhuǎn)變。
3.3.2pH響應(yīng)性材料
基于聚離子液體膜還可用于制備pH響應(yīng)性材料。Zhao等將咪唑鹽聚離子液體和聚丙烯酸的混合物澆筑成膜,通過和氨水或NaOH溶液反應(yīng)得到納米多孔聚離子液體薄膜。這種薄膜材料在水溶液或有機溶液中能穩(wěn)定存在,具有快響應(yīng)(tr=5 s,tf=12 s)和靈敏度高(2.04~2.48 nm/p H unit)等優(yōu)點[31]。將離子液體單體與丙烯腈光聚成膜,得到的聚離子液體薄膜分別和甲酚紅(CR)、甲基橙(MO)、溴百里酚藍(TB)等有機染料進行陰離子交換,可以制備具有pH指示功能的響應(yīng)性薄膜(圖6)[32]。實驗結(jié)果表明, 聚離子液體薄膜在水溶液和有機溶液中均具有良好的pH響應(yīng)性,并且可以被多次重復測試利用。
3.3.3光響應(yīng)性材料
偶氮化合物中的偶氮基團具有特殊的光學活性,將偶氮基團與離子液體結(jié)合,可以通過光致變色基團的光響應(yīng)來可逆地調(diào)變離子液體的物理化學性質(zhì),從而拓寬離子液體的應(yīng)用范圍。Xie等[33]在1-乙烯基咪唑上修飾偶氮苯基團,通過自由基聚合得到具有光響應(yīng)性的聚離子液體。該聚合物具有優(yōu)良的光致變色(異構(gòu))性能,為光存儲材料和光電材料的開發(fā)提供了理論基礎(chǔ)。
聚離子液體的一個特性是可以通過離子交換法改變聚合物的性質(zhì),制備功能高分子材料[34]。例如,通過離子交換法將偶氮苯陰離子基團與聚離子液體相結(jié)合,得到的聚離子液體不僅具有良好的導電性還具有偶氮苯基團的光敏性能,從而拓寬了離子液體的應(yīng)用范圍。路慶華等通過離子交換法,合成了聚(1-乙基-4-乙烯吡啶溴)/甲基橙(MO)液晶聚合物薄膜(圖 7)[35]。所制備的液晶聚合物薄膜光響應(yīng)迅速,雙折射數(shù)值達0.067,光誘導各向異性穩(wěn)定性好,有望用于光學和液晶顯示材料領(lǐng)域。
3.3.4溶劑響應(yīng)性材料
近年來,基于環(huán)糊精超分子的聚合物得到了廣泛而深入的研究。嚴鋒等將離子液體單體(含 TFSI-)與丙烯酸共聚得到聚離子液體凝膠,在玻璃化轉(zhuǎn)變溫度(>Tg:78℃)以上使其發(fā)生形變(見圖8),并浸泡于環(huán)糊精溶液中,由于TFSI-和環(huán)糊精發(fā)生主客體作用形成了親水性的包合物,聚離子液體由疏水聚合物變?yōu)橛H水性聚合物凝膠,形變后的凝膠通過吸收水分快速恢復其初始形態(tài),從而顯示出形狀記憶效應(yīng)[36]。
3.3.5氧化還原刺激響應(yīng)聚合物“搭扣”
主客體作用作為一個微觀結(jié)構(gòu)的作用力,要實現(xiàn)其在宏觀結(jié)構(gòu)的表現(xiàn)則需在設(shè)計材料時考慮其宏觀表現(xiàn)。在離子液體單體與丙烯腈、丙烯酸共聚得到聚離子液體薄膜表面分別修飾接枝上主體(β-環(huán)糊精)和客體(二茂鐵)分子,可制備“搭扣”式聚離子液體薄膜(見圖9)[37]。離子液體官能團的引入使得該聚合物“搭扣”還可以通過電化學氧化還原調(diào)控其貼合與分離。
3.4碳材料
納米碳材料在電子傳導能力和吸附能力等方面都具備常規(guī)材料無法比擬的優(yōu)勢。而多孔碳材料因具有高比表面積、高孔隙率、良好的導電性和導熱性、可調(diào)控的孔徑和表面性能,在催化劑、催化劑載體、超級電容器、吸附劑和氣體儲存等領(lǐng)域有廣泛應(yīng)用[38~41]。
離子液體由于具有室溫低揮發(fā)性,較高離子電導率,良好熱穩(wěn)定性、較低的揮發(fā)度等特性。這些特性使離子液體成為制備碳材料理想選擇。另外,由于離子液體的分子可設(shè)計性,可以制備氮、硫、磷、硼等單摻雜提供了可能。嚴鋒等以離子液體1-甲基-3-丁基咪唑二氰胺鹽為前驅(qū)體制備氮摻雜多孔碳材料,組裝超級電容器電極。該超級電容器具有良好的電化學性能[42]。Yuan等[43]利用聚離子液體為前驅(qū)體,以FeCl2為催化劑,900 ℃碳化制備得高導電性、介孔石墨化碳材料(如圖10所示)。該合成過程介入金屬鹽,催化生長厚度在5~20 nm石墨化片層狀納米結(jié)構(gòu)碳材料,避免了模板劑的使用。由于聚合物骨架的非流動性,碳產(chǎn)率可達 29.7%,而聚離子液體中含有的雜原子,使得碳材料本身具有雜原子基團,在催化、超級電容器、鋰離子電池等電化學領(lǐng)域具有較好的應(yīng)用前景。
嚴鋒課題組將 1-丁基-3-乙烯基咪唑溴離子液體單體按不同比例與丙烯腈共聚,在 800℃下直接碳化后即得到相應(yīng)碳材料。為合成氮摻雜C/Pt納米雜化材料,合成的共聚物可以先與鉑的前驅(qū)體氯鉑酸(H2PtCl6·6H2O)通過陰離子交換生成[PBA][PtCl6],碳化[PBA][PtCl6]即得到相應(yīng)氮摻雜 C/Pt納米雜化材料。由于制備的鉑納米粒子高度分散在氮摻雜的碳材料表面,及電化學表面較高的電子轉(zhuǎn)移速率等因素,使得C/Pt納米雜化材料具有增強的甲醇催化氧化反應(yīng)活性和穩(wěn)定性。與此同時,氮摻雜的碳材料增加了碳材料的堿性度,氮元素位點上提供了孤對電子,同時增加了吡啶類官能團對Pt的電子授予能,對氮摻雜C/Pt納米雜化材料的甲醇催化氧化反應(yīng)活性和穩(wěn)定性的提高起到了重要作用[44]。
Guo等[45]以SiO2納米粒子為模板劑,表面原位聚合接枝聚離子液體。碳化后移除模板劑,得到空心碳球。該空心碳球展示了良好的導電性,高比表面積和孔隙率。Balach 等[46]使用類似的方法制備含氮元素摻雜的空心碳球(圖 10)。該碳材料用作Fe2O3納米顆粒的負載主體應(yīng)用于鋰離子電池電極材料。在 0.1 A/g的充放電速率下,碳基復合材料表現(xiàn)了較高的可逆容量,達到1120 mAh/g。
聚離子液體作為一種新型的聚合物,近年來成為國內(nèi)外研究的熱點。目前,研究熱點主要集中在聚離子液體的分子設(shè)計、組成-結(jié)構(gòu)-性能關(guān)系,以及功能材料的制備。隨著離子液體與聚離子液體理論研究的深入及應(yīng)用技術(shù)的發(fā)展,需要按照離子液體與聚離子液體產(chǎn)品的結(jié)構(gòu)和性能的需求進行精細設(shè)計,合成更多性能優(yōu)異的新型功能離子液體與聚離子液體材料,豐富其基礎(chǔ)化學理論。雖然針對聚離子液體的研究范圍已擴展到電學、光學和與生物相關(guān)的研究領(lǐng)域, 但聚離子液體的研究仍處于起步階段,其潛在應(yīng)用前景十分廣闊。
·高被引論文摘要·
被引頻次:482
離子液體研究進展
石家華,孫遜,楊春和,等
離子液體作為一類新型的環(huán)境友好的“綠色溶劑”,具有很多獨特的性質(zhì),在很多領(lǐng)域有著誘人的應(yīng)用前景。本文對離子液體的合成、結(jié)構(gòu)、性能及應(yīng)用等方面的研究進展進行了綜述。
離子液體;合成方法;溶劑;液體提取;電化學研究
來源出版物:化學通報, 2002, 65(4): 243-250
被引頻次:302
1-烯丙基,3-甲基咪唑室溫離子液體的合成及其對纖維素溶解性能的初步研究
任強,武進,張軍,等
摘要:隨著不可再生資源(如石油、天然氣、煤礦和金屬礦藏等)的急劇耗竭,天然高分子的開發(fā)與利用日益引起世人的關(guān)注。纖維素作為自然界中最豐富的天然高分子材料,其開發(fā)與利用一直備受關(guān)注。但由于天然纖維素較高的結(jié)晶度和分子間和分子內(nèi)存在大量的氫鍵,使其具有不熔化、在大多數(shù)溶劑中不溶解的特點,這成為纖維素在應(yīng)用開發(fā)中的最大障礙。開發(fā)有效的纖維素溶劑體系是解決這一難題的關(guān)鍵。研究較多的纖維素溶劑主要有銅氨溶液、N-甲基嗎啉-N-氧化物(NMMO)溶劑體系,氯化鋰 二甲基乙酰胺(LiCl DMAC)溶劑體系等,而這些溶劑或多或少存在著不穩(wěn)定、有毒害、不易回收、價格昂貴等缺點。開發(fā)低成本、環(huán)境友好的纖維素溶劑仍然是這一領(lǐng)域的發(fā)展趨勢。
關(guān)鍵詞:室溫離子液體;溶解;纖維素
來源出版物:高分子通報, 2003, 6(3): 448-451
被引頻次:302
綠色溶劑——離子液體的制備與應(yīng)用
李汝雄,王建基
摘要:合成的離子液體已達一百多種。離子液體作為溶劑可用于分離過程、化學反應(yīng),特別是催化反應(yīng)、以及電化學等方面,并已取得許多良好的實驗結(jié)果。離子液體易于循環(huán)利用從而減少對環(huán)境的污染,被稱為綠色溶劑。
關(guān)鍵詞:離子液體;溶劑;催化;環(huán)境保護
來源出版物:化工進展, 2002, 21(1): 43-47
被引頻次:298
室溫離子液體:合成、性質(zhì)及應(yīng)用
趙東濱,寇元
摘要:室溫離子液體是一類熔點在室溫附近的熔融鹽,以其熔點低、蒸氣壓小、電化學窗口大、酸性可調(diào)及良好的溶解度、粘度、密度等特點已經(jīng)或正在電化學、有機合成、催化、分離等領(lǐng)域被廣泛應(yīng)用,并因其對環(huán)境友好吸引了工業(yè)上的興趣。
關(guān)鍵詞:室溫離子液體;蒸氣壓;電化學窗口;熔融鹽
來源出版物:大學化學, 2002, 17(1): 42-46
被引頻次:294
離子液體的性質(zhì)及其在催化反應(yīng)中的應(yīng)用
王均鳳,張鎖江,陳慧萍,等
摘要:在對離子液體的國內(nèi)外研究現(xiàn)狀綜合分析的基礎(chǔ)上,對離子液體的結(jié)構(gòu)性能關(guān)系和性質(zhì)變化規(guī)律進行了探討,系統(tǒng)地介紹了離子液體作為溶劑或催化劑在催化反應(yīng)中的應(yīng)用,特別是在金屬催化、生物催化、反應(yīng)分離耦合方面的進展。在含微量水或無水離子液體中酶能夠保持高的活性和選擇性,有望在生物催化方面帶來突破性進展。超臨界CO2/離子液體及離子液體/水/有機相提供了一種新的反應(yīng)分離耦合模式,將進一步推動綠色化學的發(fā)展。
關(guān)鍵詞:離子液體;綠色溶劑;性質(zhì);催化反應(yīng);超臨界流體
來源出版物:過程工程學報, 2003, 3(2): 177-185
被引頻次:222
離子液體的合成與應(yīng)用
李汝雄,王建基
摘要:離子液體即在常溫及附近溫度下為液體的離子物質(zhì),已合成的離子液體已達上百種。離子液體的合成方法有復分解法和中和法,其應(yīng)用研究領(lǐng)域有分離過程、化學反應(yīng)特別是催化反應(yīng)以及電化學等方面。
關(guān)鍵詞:離子液體;合成;應(yīng)用
來源出版物:化學試劑, 2001, 23(4): 211-215
被引頻次:221
室溫離子液體及其在催化和有機合成中的應(yīng)用
顧彥龍,彭家建,喬琨,等
摘要:介紹了室溫離子液體的制備、性質(zhì)及其在催化和有機反應(yīng)中的應(yīng)用。
關(guān)鍵詞:室溫離子液體;制備;性質(zhì);應(yīng)用
來源出版物:化學進展, 2003, 15(3): 222-241
被引頻次:213
室溫離子液體:一類新型的軟介質(zhì)和功能材料
顧彥龍,石峰,鄧友全
摘要:對室溫離子液體作為一種新型的介質(zhì)在催化、有機合成、電化學、分離分析中的應(yīng)用以及作為功能材料在摩擦與潤滑、敏感材料、儲能和光電材料等方面的研究進展作了綜述,并對離子液體研究未來的發(fā)展作了展望。
關(guān)鍵詞:離子液體;反應(yīng)介質(zhì);功能材料;綠色化學
來源出版物:科學通報, 2004, 49(6): 515-521
被引頻次:188
不斷壯大的離子液體家族
楊雅立,王曉化,寇元,等
摘要:本文對近10年來出現(xiàn)的新型離子液體進行了分類綜述,并對其發(fā)展前景提出了一些見解。
關(guān)鍵詞:離子液體;任務(wù)專一性
來源出版物:化學進展, 2003, 15(6): 471-476
被引頻次:187
功能化離子液體對纖維素的溶解性能研究
羅慧謀,李毅群,周長忍
摘要:功能化離子液體氯化1-(2-羥乙基)-3-甲基咪唑鹽是纖維素的新型良溶劑,在70℃時微晶纖維素的溶解能力達到5%~7%。向離子液體纖維素溶液中加入去離子水可獲得再生纖維素。用XRD,F(xiàn)T-IR和TGA對再生纖維素進行了表征,IR和XRD數(shù)據(jù)表明,功能化離子液體是纖維素的直接溶劑,但TGA數(shù)據(jù)則表明再生纖維素的熱穩(wěn)定性有所降低,熱失重殘留物有所增加。對溶解機理進行了初步討論。
關(guān)鍵詞:功能化離子液體;纖維素;溶解
來源出版物:高分子材料科學與工程, 2005, 21(2): 233-235
被引頻次:872
來源出版物:Journal of the American Chemical Society, 2002, 124(6): 926-927
被引頻次:839
Metal chlorides in ionic liquid solvents convert sugars to 5-hydroxymethylfurfural
Zhao, HB; Holladay, JE; Brown, H
Abstract: Replacing petroleum feedstocks by biomass requires efficient methods to convert carbohydrates to a variety of chemical compounds. We report the catalytic conversion of sugars giving high yield to 5-hydroxymethylfurfural (HMF), a versatile intermediate. Metal halides in 1-alkyl-3-methylimidazolium chloride are catalysts, among which chromium (II) chloride is found to be uniquely effective, leading to the conversion of glucose to HMF with a yield near 70%. A wide range of metal halides is found to catalyze the conversion of fructose to HMF. Only a negligible amount of levulinic acid is formed in these reactions.
來源出版物:Science, 2007, 316(5831): 1597-1600
被引頻次:773
The phase behaviour of 1-alkyl-3-methylimidazolium tetrafluoroborates; ionic liquids and ionic liquid crystals
Holbrey, JD; Seddon, KR
Abstract: Air-and water-stable 1-alkyl-3-methylimidazolium tetrafluoroborate salts with the general formula [C-n-mim][BF4] (n=0-18) have been prepared by metathesis from the corresponding chloride or bromide salts. The salts have been characterised by H-1 NMR and IR spectroscopy, microanalysis, polarising optical microscopy and differential scanning calorimetry. Those with short alkyl chains (n=2-10) are isotropic ionic liquids at room temperature and exhibit a wide liquid range, whereas the longer chain analogues are low melting mesomorphic crystalline solids which display an enantiotropic smectic A mesophase. The thermal range of the mesophase increases with increasing chain length and in the case of the longest chain salt prepared, [C-18-mim][BF4], the mesophase range is ca. 150 degrees C.
Keywords: temperature molten-salts; clean technology; hydrogenation; solvents; cation; air
來源出版物:Journal of the Chemical Society, Dalton Transactions, 1999(13): 2133-2140
被引頻次:663
Gelation of ionic liquid-based electrolytes with silica nanoparticles for quasi-solid-state dye-sensitized solar cells
Wang, P; Zakeeruddin, SM; Comte, P; et al.
Abstract: For the first time silica nanoparticles were used to solidify ionic liquids. These ionic liquid-based quasi-solid-state electrolytes were successfully employed for regenerative photoelectrochemical cells that yielded 7% efficiency at AM 1.5 sunlight in combination with an amphiphilic ruthenium polypyridyl photosensitizer.
來源出版物:Journal of the American Chemical Society, 2003, 125(5): 1166-1167
被引頻次:598
1-Allyl-3-methylimidazolium chloride room temperature ionic liquid: A new and powerful nonderivatizing solvent for cellulose
Zhang, H; Wu, J; Zhang, J; et al.
Abstract: A new and highly efficient direct solvent, 1-allyl-3-methylimidazolium chloride (AMIMCI), has been used for the dissolution and regeneration of cellulose. The cellulose samples without any pretreatment were readily dissolved in AMIMCI. The regenerated cellulose materials prepared by coagulation in water exhibited a good mechanical property. Because of its thermostable and nonvolatile nature, AMIMCI was easily recycled. Therefore, a novel and nonpolluting process for the manufacture of regenerated cellulose materials using AMIMCI has been developed in this work.
Keywords: N,N-dimethylacetamide lithium-chloride; infrared-spectra; derivatives; dissolution; behavior; blends; water; regeneration
來源出版物:Macromolecules, 2005, 38(20): 8272-8277
被引頻次:579
High-pressure phase behavior of ionic liquid/CO2systems
Blanchard, LA; Gu, ZY; Brennecke, JF
Abstract: This work presents the high-pressure phase behavior of CO2with six ionic liquids: 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6)], 1-n-octyl-3-methylimidazolium hexafluorophosphate ([C-8-mim][PF6]), 1-n-octyl-3-methylimidazolium tetrafluoroborate ([CB-mim][BF4]), 1-n-butpl-3-methylimidazolium nitrate ([bmim][NO3]), 1-ethyl-3-methylimidazolium ethyl sulfate([emim][EtSO4]), and N-butylpyridinium tetrafluoroborate ([N-bupy][BF4]). We explored the effect of systematically changing the anionic and cationic components of the ionic liquid on the CO2-ionic liquid phase behavior. For all of the ionic liquids tested, large quantities of CO2dissolved in the ionic liquid phase, but no appreciable amount of ionic liquid solubilized in the CO2phase. In addition, the liquid phase volume expansion with the introduction of even large amounts of CO2is negligible, in dramatic contrast to the large volume expansion observed for neutral organic liquids. Our results seek to elucidate the underlying physical mechanisms of this highly unusual phase behavior.
Keywords: carbon-dioxide; solvents; water; equilibrium; extraction; catalysis; products; CO2
來源出版物: The Journal of Physical Chemistry B, 2001, 105(12): 2437-2444
被引頻次:575
Solubilities and thermodynamic properties of gases in the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate
Anthony, JL; Maginn, EJ; Brennecke, JF
Abstract: This work presents the solubility of nine different gases in 1-n-butyl-3-methylimidazolium hexafluorophosphate. The gases considered include carbon dioxide, ethylene, ethane, methane, argon, oxygen, carbon monoxide, hydrogen, and nitrogen. We also report the associated Henry's constants and enthalpies and entropies of absorption. We found carbon dioxide to have the highest solubility and strongest interactions with the ionic liquid, followed by ethylene and ethane. Argon and oxygen had very low solubilities and immeasurably weak interactions. Carbon monoxide, hydrogen, and nitrogen all had solubilities below the detection limit of our apparatus. Our results suggest that the mass transfer of gases into ionic liquids likely will be an important issue for reactions involving these gases. We also determined that ionic liquids show good potential for use as a gas-separation medium.
Keywords: equation-of-state; catalytic-hydrogenation; fluid region; temperature; pressures; solvents; water; CO2; imidazolium; argon
來源出版物:The Journal of Physical Chemistry B, 2002, 106(29): 7315-7320
被引頻次:478
Properties of ionic liquid solvents for catalysis
Wilkes, JS
Abstract: Ionic liquids are good solvents for catalytic reactions. The rational selection of the appropriate ionic liquid solvent for a particular reaction requires general knowledge of the properties of ionic liquids, and the details of some properties of the specific ionic liquid solvents being considered. The solvent properties of ionic liquids that are relevant to catalysis are discussed, and sources of the values of those properties for ionic liquids are identified. A roadmap for the literature values of density, viscosity, melting and glass transition temperatures, thermal stability, empirical solvent parameters, absorption, toxicity, surface tension, heat capacity, and thermal conductivity is provided.
Keywords: density; viscosity; melting and glass transition temperatures; thermal stability empirical solvent parameters; absorption; toxicity;surface tension; heat capacity; thermal conductivity
來源出版物: Journal of Molecular Catalysis A: Chemical, 2004, 214(1): 11-17
被引頻次:475
Ionic liquid crystals: hexafluorophosphate salts
Gordon, CM; Holbrey, JD; Kennedy, AR; et al.
Abstract: A series of novel hexaflurophosphate salts, based on N,N'-dialkylimidazolium and substituted N-alkylpyridinium cations, display liquid crystalline behaviour at temperatures above their melting point. The temperature range over which liquid crystalline behaviour is observed increases markedly with increasing alkyl chain length. Alkyl substitution at the 3- and 4-positions on the pyridinium ring results in a decrease in the melting point compared with the equivalent unsubstituted salt, but also leads to a large decrease in the tendency towards liquid crystalline behaviour (or mesogenicity). The salts prepared are fully characterised using a wide variety of techniques, including NMR and IR spectroscopy, DSC, and single crystal X-ray diffraction in the case of 1-dodecyl-3-methylimidazolium hexafluorophosphate. The effect of preparing mixtures containing different proportions of two cations is also reported.
Keywords: temperature molten-salts; mesogenic group; behavior; polymorphism; complexes; halides; model
來源出版物:Journal of Materials Chemistry, 1998, 8(12): 2627-2636
被引頻次:468
The room temperature ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate: Electrochemical couples and physical properties
Fuller, J; Carlin, RT; Osteryoung, RA
Abstract: The room temperature ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMLBF4) was demonstrated,as a versatile electrolyte by examining three representative electrochemical couples: ferrocene and tetrathiafulvalene oxidations and lithium ion reduction. Square-wave voltammetric data for ferrocene oxidation were fit to a reversible one-electron process using the COOL11 algorithm to give a half-wave potential of 0.490 V vs. Al/Al(III) and a diffusion coefficient of 5.1 × 10-7cm2/s-1. The two-electron oxidation of tetrathiafulvalene was reversible and proceeded through two consecutive one-electron steps; although data collected at lower square-wave frequencies indicated a slow precipitation of the TTF+species. Lithium ion was reduced to lithium metal at a Pt electrode following the addition of water to the EMLBF4 electrolyte, whereas Lithium ion reduction at an Al wire produced-the beta-LiAl alloy. Conductivities and kinematic viscosities of EMIBF4 were measured from 20 to 100 degrees C and had values of 14 mS cm-1and 0.275 cm2/s-1, respectively, at 25 degrees C.
Keywords: kinetic-parameters; molten-salts; voltammetry
來源出版物:Journal of the Electrochemical Society, 1997, 144(11): 3881-3886
·推薦論文摘要·
聚離子液體功能材料研究進展
錢文靜,袁超,郭江娜,等
摘要:聚離子液體(PILs)材料兼具離子液體和聚合物的性質(zhì),近年來已經(jīng)在高分子化學、材料科學及能源科學等領(lǐng)域得到初步應(yīng)用,并引起了人們廣泛關(guān)注.本論文介紹了聚離子液體的合成,綜述其在(準)固態(tài)電解質(zhì)、燃料電池聚電解質(zhì)膜、刺激響應(yīng)性功能材料,以及碳材料等相關(guān)領(lǐng)域的研究與應(yīng)用。
關(guān)鍵詞:聚離子液體;固態(tài)電解質(zhì);功能材料;碳材料;刺激響應(yīng)
來源出版物:化學學報, 2015, 73: 310-315 聯(lián)系郵箱:嚴鋒,fyan@suda.edu.cn
功能性離子液體萃取水溶液中Cu2+:實驗與理論
劉夢瑩, 車佳寧,吳蔚閎,等
摘要:本工作針對含硫脲基咪唑憎水功能離子液體在溶液中Cu2+萃取方面的應(yīng)用及其機理進行研究??疾炝溯腿上囿w積比、金屬離子濃度、時間、無機鹽 Na Cl、溶液 pH及離子液體烷基鏈長等因素的影響。結(jié)果表明:室溫條件下,0.1 mL離子液體[CnMPSM][PF6](n=4、6、8)與5 mL 21.94 mg/L的氯化銅溶液室溫條件下超聲混合30 min,溶液中Cu2+的去除率即超過95%;且此類離子液體對金屬離子的萃取效果順序為:n=4≈n=6>n=8。以[HMPSM][PF6]為研究對象,發(fā)現(xiàn)溶液中無機鹽NaCl的含量以及溶液pH對金屬離子的萃取效果影響不明顯。與傳統(tǒng)離子液體[Cnbim][PF6](n=6、8)相比,硫脲基的引入使其萃取率由20%左右提高到99%,且有效避免因陽離子交換而引起水中咪唑陽離子含量增加問題。通過理論計算發(fā)現(xiàn),功能離子液體對金屬離子的萃取依賴于官能團中的S元素與Cu2+之間較強的靜電及路易斯酸堿作用,與萃取實驗中離子液體未和Cu2+發(fā)生陽離子交換作用相吻合。關(guān)鍵詞:硫脲;離子液體;萃??;金屬銅離子;計算
來源出版物:化學學報, 2015, 73: 116-125 聯(lián)系郵箱:楊強,qyang@ecust.edu.cn
Lewis酸性離子液體催化合成丁二酸二異丙酯
趙地順,葛京京,翟建華,等
摘要:采用兩步法制備了9種不同的Lewis酸性離子液體,采用1H NMR、FT-IR對離子液體的結(jié)構(gòu)進行了表征,并系統(tǒng)地考察了其對丁二酸和異丙醇酯化反應(yīng)的催化性能。結(jié)果表明,離子液體隨著鹵化物用量增加表現(xiàn)出更強的酸性。其中[Bmim]Br-Fe2Cl6催化合成丁二酸二異丙酯效果良好,催化劑用量為丁二酸質(zhì)量的10.0%,反應(yīng)溫度100℃,反應(yīng)時間4 h,酸醇摩爾比為1︰5,丁二酸二異丙酯收率為88.9%,酯化率達92.7%。離子液體重復使用6次后,產(chǎn)品收率下降1.7%。
關(guān)鍵詞:離子液體;Lewis酸;酯化;丁二酸二異丙酯;催化劑
來源出版物:化工學報, 2014, 65(2): 561-569 聯(lián)系郵箱:趙地順,zhao_dsh@hebust.edu.cn
離子液體[BMIM]PF6中鉻的電沉積行為
玉山江·哈斯木,劉瑞泉,米紅宇
摘要:以一氯丁烷、N-甲基咪唑和KPF6為原料,合成了1-丁基-3-甲基咪唑六氟磷酸鹽離子液體([BMIM]PF6),用紅外光譜(IR)對產(chǎn)物進行了結(jié)構(gòu)分析。用循環(huán)伏安法測試該離子液體在85℃下的電化學窗口為4.7 V??疾炝耍跙MIM]PF6-Cr(Ⅲ)電解液的電化學行為,結(jié)果表明,在85℃下Cr(Ⅲ)的還原過程是受擴散控制的一步還原不可逆過程,Cr(Ⅲ)的傳遞系數(shù)α=0.023,陰極擴散系數(shù)D0=1.142×10-6cm2/s。在85℃和-1.5 V條件下,用恒電勢法在銅片上電沉積Cr(Ⅲ),并通過掃描電子顯微鏡(SEM)觀察了銅片上鍍層的表面結(jié)構(gòu),發(fā)現(xiàn)該鍍層呈顆粒狀,且顆粒的體積隨沉積時間的延長而增大.X射線能量色散譜(EDS)和X射線粉末衍射(XRD)測試結(jié)果表明,該鍍層為無定形的金屬鉻。
關(guān)鍵詞:鉻;離子液體;循環(huán)伏安;電化學窗口;電沉積
來源出版物:高等學?;瘜W學報, 2013, 35(1): 140-145 聯(lián)系郵箱:劉瑞泉,liu.rq@163.com
基于離子液體的綠色催化過程
孫劍,王金泉,王蕾,等
摘要:離子液體為構(gòu)建綠色催化反應(yīng)過程提供了新途徑。本文簡要評述了離子液體在幾個代表性催化反應(yīng)中的研究進展,如CO2羰基化、烷基化、酯交換、氧化、CO2加氫、共聚以及PET降解等;分析討論了離子液體的特點和優(yōu)勢,如提高反應(yīng)活性、降低廢物排放以及簡化分離等,并對離子液體催化反應(yīng)的未來發(fā)展方向進行了展望。
關(guān)鍵詞:離子液體;綠色催化;反應(yīng)過程
來源出版物:中國科學:化學(中文版), 2014, 44(1): 100-113 聯(lián)系郵箱:張鎖江,sjzhang@home.ipe.ac.cn
功能化離子液體-MDEA復配體系吸收CO2
王占麗,徐凡,邢小林,等
摘要:采用一步法合成了兩種功能化離子液體四乙銨-丙氨酸鹽([N2222][Ala])和四乙銨-絲氨酸鹽([N2222][Ser]),利用IR和1H NMR對其結(jié)構(gòu)進行了表征,并測定了其玻璃轉(zhuǎn)化溫度和分解溫度;同時,在40℃下分別將[N2222][Ala]和[N2222][Ser]與MDEA進行復配,考察復配后的體系對CO2吸收性能;實驗結(jié)果表明,[N2222][Ala]和[N2222][Ser]的加入對MDEA吸收CO2均有不同程度的增強作用,當加入質(zhì)量分數(shù)為10%時,體系對CO2吸收量分別增加了8.63%和5.40%。此外,研究了20~60℃溫度范圍內(nèi)復配體系的密度、黏度等,并比較了吸收前后黏度的變化。
關(guān)鍵詞:N-甲基二乙醇胺;離子液體;二氧化碳;吸收
來源出版物:化工進展, 2013, 32(2): 394-399 聯(lián)系郵箱:任保增,renbz@zzu.edu.cn
膽堿類低共熔溶劑的物性及應(yīng)用
張盈盈,陸小華,馮新,等
摘要:作為一種新型的離子液體,膽堿類低共熔溶劑具有相比于其他離子液體更為突出的特點,如低毒、生物可降解、價格低廉等,這些特點使得此類離子液體在綠色化學和工程化學中受到越來越多的關(guān)注。本文分析了膽堿類低共熔溶劑的凝固點、熔點、溶解度、黏度、表面張力、電導率等物性隨溫度、組成、水分等因素的變化及理論預(yù)測模型,并介紹了膽堿類低共熔溶劑在潤滑、功能材料制備、電化學、有機合成及生物質(zhì)催化轉(zhuǎn)化等方面的潛在應(yīng)用。最后就膽堿類低共熔溶劑研究及應(yīng)用中存在的問題及難點對其前景做出展望。
關(guān)鍵詞:膽堿;離子液體;凝固點;溶解度;黏度;表面張力;電導率
來源出版物:化學進展, 2013, 25(6): 881-892 聯(lián)系郵箱:陸小華,xhlu@ njut.edu.cn
Ion structure controls ionic liquid near-surface and interfacial nanostructure
Elbourne, A; Voitchovsky, K; Warr, GG; et al.
Abstract: A unique, but unifying, feature of ionic liquids (ILs) is that they are nanostructured on the length scale of the ions; in many ILs well-defined polar and apolar domains exist and may percolate through the liquid. Near a surface the isotropic symmetry of the bulk structure is broken, resulting in different nanostructures which, until now, have only been studied indirectly. In this paper, in situ amplitude modulated atomic force microscopy (AM-AFM) has been used to resolve the 3-dimensional nanostructure of five protic ILs at and near the surface of mica. The surface and near surface structures are distinct and remarkably well-defined, but are very different from previously accepted descriptions. Interfacial nanostructure is strongly influenced by the registry between cations and the mica surface charge sites,whereas near surface nanostructure is sensitive to both cation and anion structure. Together these ILs reveal how interfacial nanostructure can be tuned through ion structure, informing “bottom-up” design and optimisation of ILs for diverse technologies including heterogeneous catalysis, lubrication, electrochemical processes, and nanofluids.
Keywords: scanning-tunneling-microscopy; atomic-force microscopy; alkyl chain-length; double-layer; physicochemical properties;molecular-dynamics; materials science; clean technology; molten-salts; temperature
來源出版物:Chemical Science, 2015, 6(1): 527-536 聯(lián)系郵箱:TAtkin, R; rob.atkin@newcastle.edu.au
Rare-earth recycling using a functionalized ionic liquid for the selective dissolution and revalorization of Y2O3:Eu3+ from lamp phosphor waste
Dupont, D; Binnemans, KPoly(vinyl ester 1,2,3-triazolium)s: a new member of the poly(ionic liquid)s family
Abstract: The supply risk for certain rare-earth elements (REEs) has sparked the development of recycling schemes for end-of-life products like fluorescent lamps. In this paper a new recycling process for lamp phosphor waste is proposed based on the use of the functionalized ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf2N]. This innovative method allows the selective dissolution of the valuable red phosphor Y2O3: Eu3+(YOX) without leaching the other constituents of the waste powder (other phosphors,glass particles and alumina). A selective dissolution of YOX is useful because this phosphor contains 80 wt% of the REEs although it only represents 20 wt% of the lamp phosphor waste. The proposed recycling process is a major improvement compared to currently used hydrometallurgical processes where the non-valuable halophosphate (HALO) phosphor (Sr,Ca)(10)(PO4)(6)(Cl,F(xiàn))(2) : Sb3+, Mn2+is inevitably leached when attempting to dissolve YOX. Since the HALO phosphor can make up as much as 50 wt% of the lamp phosphorwaste powder, this consumes significant amounts of acid and complicates the further processing steps (e.g. solvent extraction). The dissolved yttrium and europium can be recovered by a single stripping step using a stoichiometric amount of solid oxalic acid or by contacting the ionic liquid with a hydrochloric acid solution. Both approaches regenerate the ionic liquid, but precipitation stripping with oxalic acid has the additional advantage that there is no loss of ionic liquid to the water phase and that the yttrium/europium oxalate can be calcined as such to reform the red Y2O3: Eu3+phosphor (purity>99.9 wt%), effectively closing the loop after only three process steps. The red phosphor prepared from the recycled yttrium and europium showed excellent luminescent properties. The resulting recycling process for lamp phosphor waste consumes only oxalic acid and features a selective leaching, a fast stripping and an immediate revalorization step. Combined with the mild conditions, the reusability of the ionic liquid and the fact that no additional waste water is generated, this process is a very green and efficient alternative to traditional mineral acid leaching.
Keywords: spent fluorescent lamps; solubilizing metal-oxides; of-the-art; solvent-extraction; aqueous-phase; recovery; separation; mercury;membrane; nickel
來源出版物:Green Chemistry, 2015, 17(2): 856-868 聯(lián)系郵箱:Dupont, D; Koen.Binnemans@chem.kuleuven.be
Obadia, MM; Colliat-Dangus, G; Debuigne, A; et al.
Abstract: A vinyl ester monomer carrying a pendant 1,2,3-triazole group is synthesized in two steps and polymerized by cobalt-mediated radical polymerization. Subsequent alkylation with N-methyl bis[(trifluoromethyl) sulfonyl]imide affords the corresponding poly(vinyl ester 1,2,3-triazolium). This unprecedented example of poly(vinyl ester ionic liquid) exhibits an ionic conductivity of 9.2 × 10-7S cm-1at 30 degrees C.
Keywords: mediated radical polymerization; click chemistry polyaddition; ionic liquids; functionalization; versatile; polymers
來源出版物:Chemical Communications, 2015, 51(16): 3332-3335 聯(lián)系郵箱:Drockenmuller, E; eric.drockenmuller@univ-lyon1.fr
1,2,3-Triazolium-Based Poly(ionic liquid)s with Enhanced Ion Conducting Properties Obtained through a Click Chemistry Polyaddition Strategy
Mudraboyina, BP; Obadia, MM; Allaoua, I; et al.
Abstract: 1,2,3-Triazolium-based poly(ionic liquid)s containing a triethylene glycol spacer were synthesized from the polyaddition of an alpha- azide-omega-alkyne monomer by copper-catalyzed azide-allcyne cycloaddition (CuAAC) followed by quaternization reactions with alkyl halides and subsequent anion exchanges with different fluorinated salts. A detailed structure-property relationship for solubility,thermal stability, and ionic conductivity was investigated by means of H-1 NMR spectroscopy, differential scanning calorimetry (DSC),thermogravinietric analysis (TGA), and broadband dielectric spectroscopy (BDS). One of these poly(ionic liquid)s with a methyl substituent and bis(trifluoromethylsulfonyl)imide anion exhibits an ionic conductivity of 2 × 10-5S cm-1at 30 degrees C, which is on par with the best PILs with side-chain charge carriers reported so far and is much higher than any previously reported ionenes. The straightforward synthesis along with the broad structural design and enhanced properties of this new class of poly(ionic liquid)s offer both fundamental and applicative perspectives.
Keywords: solid polymer electrolytes; step-growth polymerization; sensitized solar-cells; omega-alkyne monomers; 1,3-dipolar cycloadditions; poly (pyridinium salt) s; terminal alkynes; ammonium ionenes; material science; crystalline
來源出版物:Chemistry of Materials, 2014, 26(4): 1720-1726 聯(lián)系郵箱:Drockenmuller, E; eric.drockenmuller@univ-lyon1.fr
Preparation of sphere-like g-C3N4/BiOI photocatalysts via a reactable ionic liquid for visible-light-driven photocatalytic degradation of pollutants
Di, J; Xia, JX; Yin, S; et al.
Abstract: Novel sphere-like g-C3N4/BiOI composite photocatalysts were prepared by a one-pot EG-assisted solvothermal process in the presence of reactable ionic liquid 1-butyl-3-methylimidazolium iodine ([Bmim]I). The nanostructured heterojunction was formed with g-C3N4covering the surface of BiOI microspheres uniformly. Multiple techniques were applied to investigate the structure, morphology and photocatalytic properties of as-prepared samples. During the reactive process, the ionic liquid acted as solvent, reactant, template and dispersing agent at the same time, leading to g-C3N4being uniformly dispersed on the sphere-like BiOI surface. Three different types of dyes rhodamine B (RhB), methylene blue (MB), methyl orange (MO) were chosen as model pollutants to evaluate the photocatalytic activity of g-C3N4/BiOI composite. The as-prepared g-C3N4/BiOI composite exhibited much higher photocatalytic activity than the pure BiOI. At the same time, colourless endocrine disrupting chemical bisphenol A (BPA) and phenols 4-chlorophenol (4-CP) were chosen to further evaluate the photocatalytic activity of g-C3N4/BiOI composite. The g-C3N4/BiOI composite also exhibited much higher photocatalytic activity than the pure BiOI, which showed a broad spectrum of photocatalytic degradation activities. The results indicated that the formed heterojunction of g-C3N4covers the BiOI microspheres contributed to improved electron-hole separation and enhancement in photocatalytic activity. A photocatalytic mechanism of g-C3N4/BiOI composites is also proposed.
Keywords: graphitic carbon nitride; selective catalytic-reduction; composite photocatalysts; enhanced activity; facile synthesis; BIOX X;C3N4; irradiation; performance; nanosheets
來源出版物:Journal of Materials Chemistry A, 2014, 2(15): 5340-5351 聯(lián)系郵箱:Xia, JX; xjx@ujs.edu.cn; lhm@ujs.edu.cn
Au-ionic liquid functionalized reduced graphene oxide immunosensing platform for simultaneous electrochemical detection of multiple analytes
Liu, N; Ma, ZF
Abstract: In this work, an Au-ionic liquid functionalized reduced graphene oxide nanocomposite (IL-rGO-Au) was fabricated via the self-assembly of ionic liquid functionalized reduced graphene oxide (IL-rGO) and gold nanoparticles (AuNPs) by electrostatic interaction. The IL-rGO can be synthesized and stabilized by introducing the cations of the amine-terminated ionic liquids (IL-NH2) into the graphene oxide (GO). With the assistance of IL-NH2, AuNPs were uniformly and densely absorbed on the surfaces of the IL-rGO. The proposed IL-rGO-Au nanocomposite can be used as an immunosensing platform because it can not only facilitate the electrons transfer of the electrode surface but also provide a large accessible surface area for the immobilization of abundant antibody. To assess the performance of the IL-rGO-Au nanocomposite, a sandwich-type electrochemical immunosensor was designed for simultaneous multianalyte detection (carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) as model analytes). The chitosan (CS) coated prussian blue nanoparticles (PBNPs) or cadmium hexacyanoferrate nanoparticles (CdNPs) and loaded with AuNPs were used as distinguishable signal tags. The resulting immunosensor exhibited high selectivity and sensitivity in simultaneous determination of CEA and AFP in a single run. The linear ranges were from 0.01 to 100 ng mL-1for both CEA and AFP. The detection limits reached 0.01 ng mL-1for CEA and 0.006 ng mL-1for APP, respectively. No obvious nonspecific adsorption and cross-talk was observed during a series of analyses to detect target analytes. In addition, for the detection of clinical serum samples, it is well consistent with the data determined by the ELISA, indicating that the immunosensor provides a possible application for the simultaneous multianalyte determination of CEA and AFP in clinical diagnostics.
Keywords: au nanoparticle; ionic liquid functionalized reduced graphene oxide; electrochemical immunosensor; carcinoembryonic antigen;alpha-fetoprotein
來源出版物:Biosensors & Bioelectronics, 2014, 51: 184-190 聯(lián)系郵箱:Ma, ZF; mazhanfang@cnu.edu.cn
Unexpected performance of layered sodium-ion cathode material in ionic liquid-based electrolyte
Chagas, LG ; Buchholz, D ; Wu, LM; et al.
Abstract: The electrochemical performance of Na0.45Ni0.22Co0.11Mn0.66O2in an ionic liquid-based electrolytic solutions is reported and compared with that obtained in a conventional, carbonate-based electrolyte. Even at ambient temperature, the Na-ion intercalation material reveals a much better electrochemical performance in 10 mol% NaTFSI (or 0.45 M) in PYR14FSI electrolyte than 0.5 M NaPF6 in PC electrolyte in terms of specific capacity and cycling stability. In particular, the electrodes cycled in the IL-based electrolyte combine a capacity retention of about 80% after 100 cycles with high specific capacities (about 200 mAh g-1) and high average voltage (2.7 V vs. Na/Na+), demonstrating that Na0.45Ni0.22Co0.11Mn0.66O2is a promising cathode material for sodium-ion batteries.
Keywords: sodium; cathode material; layered compound; ionic liquid-based electrolyte; sodium battery
來源出版物:Journal of Power Sources ,2014, 247: 377-383 聯(lián)系郵箱:Passerini, S; stefano.passerini@uni-muenster.de
Gas-Liquid Mass-Transfer Properties in CO2Absorption System with Ionic Liquids
Zhang, X; Bao, D; Huang, Y; et al.
Abstract: The deficiency of mass-transfer properties in ionic liquids (ILs) has become a bottleneck in developing the novel IL-based CO2capture processes. In this study, the liquid-side mass-transfer coefficients (k(L)) were measured systematically in a stirred cell reactor by the decreasing pressure method at temperatures ranging from 303 to 323 K and over a wide range of IL concentrations from 0 to 100 wt %. Based on the data of kL, the kinetics of chemical absorption of CO2with mixed solvents containing 30 wt % monoethanolamine (MEA)and 0-70 wt % ILs were investigated. The k(L) in IL systems is influenced not only by the viscosity but also the molecular structures of ILs. The enhancement factors and the reaction activation energy were quantified. Considering both the mass-transfer rates and the stability of IL in CO2absorption system, the new IL-based system MEA + [bmim][NO3] + H2O is recommended.
Keywords: ionic liquids; carbon dioxide; mass-transfer coefficient; kinetics; absorption
來源出版物:AIChE Journal, 2014, 60(8): 2929-2939
Improving Hydrothermal Carbonization by Using Poly(ionic liquid)s
Zhang, PF; Yuan, JY; Fellinger, TP; et al.
Abstract: Functional carbonaceous materials with high specific surface areas and controllable structural compositions have been an appealing topic in recent years, owing to their wide applications in various fields. So far, a number of well-known synthetic methods including thermal pyrolysis of organic compounds, high-voltage-arc electricity, laser ablation, and chemical vapor deposition, have been developed for the preparation of carbon materials with different sizes, shapes, and chemical compositions. Nowadays, energy andsustainability issues are seriously considered when designing synthetic strategies. The recently rediscovered environmentally friendly and facile hydrothermal carbonization (HTC) procedure offers new perspectives, as it involves the use of renewable resources (e.g., cellulose)at low temperatures (130-250℃) in aqueous medium under self-generated pressure.] Materials prepared by this straightforward waterbased method are commonly nonporous and have unfavorably low surface areas (<20 m2g-1). To induce pore formation, both hard- and soft -templating strategies, and some other efficient techniques (such as the use of metal salts or protein additives) have been recently introduced into the HTC process. For example, a novel borax-mediated HTC method was reported to produce aerogel materials that have similarities to the traditional resorcinol-formaldehyde-based organic aerogels. Considering practical applications, HTC carbonaceous materials with not only porous nanostructures but also more specific features (e.g., heteroatom or metal nanoparticle doping) are highly desirable and of great potential, in particular for catalysis.
Keywords: hydrothermal synthesis; nanostructures; nitrogen doping; poly(ionic liquid)s; porous materials
來源出版物:Angewandte Chemie-International Edition ,2013, 52 (23): 6028-6032 聯(lián)系郵箱:Wang, Y; Jiayin.Yuan@mpikg.mpg.de
Outstanding performance of activated graphene based supercapacitors in ionic liquid electrolyte from-50 to 80 degrees C
Tsai, WY; Lin, RY; Murali, S; et al.
Abstract: High specific surface area (SSA similar to 2000 m2/g) porous KOH-activated microwave exfoliated graphite oxide ('a-MEGO')electrodes have been tested in a eutectic mixture of ionic liquids (1:1 by weight or molar ratio N-methyl-N-propylpiperidinium bis(fluorosulfonyl)imide (PIP13-FSI) and N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR14-FSI)) as electrolyte for supercapacitor applications. By optimizing the carbon/electrolyte system, outstanding capacitive performance has been achieved with high capacitance (up to 180 F/g) and wide electrochemical window (up to 3.5 V) over a wide temperature range from -50 degrees C to 80 degrees C. This is the first demonstration of a carbon-ionic liquid system capable of delivering capacitance in excess of 100 F/g below room temperature. The excellent electrochemical response of the proposed couple shows that optimization of the carbon/electrolyte interface is of great importance for improving capacitive energy storage.
Keywords: electrochemical capacitors; activated graphene; ionic liquid mixture; wide temperature range
來源出版物:Nano Energy, 2013, 2 (3): 403-411 聯(lián)系郵箱:Gogotsi, Y; Gogotsi@drexel.edu; simon@chimie.ups-tlse.fr
Improved Carrier Mobility in Few-Layer MoS2Field-Effect Transistors with Ionic-Liquid Gating
Perera, MM; Lin, MW; Chuang, HJ; et al.
Abstract: We report the fabrication of ionic liquid (IL)-gated field-effect transistors (FETs) consisting of bilayer and few-layer MoS2. Our transport measurements indicate that the electron mobility mu approximate to 60 cm2V-1s-1at 250 K in IL-gated devices exceeds significantly that of comparable back-gated devices. IL-FETs display a mobility increase from approximate to 100 cm2V-1s-1at 180 K to approximate to 220 cm2V-1s-1at 77 K in good agreement with the true channel mobility determined from four-terminal measurements,ambipolar behavior with a high ON/OFF ratio >10(7) (10(4)) for electrons (holes), and a near ideal subthreshold swing of approximate to 50 mV/dec at 250 K. We attribute the observed performance enhancement, specifically the increased carrier mobility that is limited by phonons, to the reduction of the Schottky barrier at the source and drain electrode by band bending caused by the ultrathin IL dielectric layer.
Keywords: field-effect transistor; MoS2; few-layer; electric double layer; Schottky barrier
來源出版物:ACS Nano ,2013, 7 (5): 4449-4458 聯(lián)系郵箱:Zhou, ZX; zxzhou@wayne.edu
A new fragment contribution-corresponding states method for physicochemical properties prediction of ionic liquids
Ying, Huang; Haifeng, Dong; Xiangping, Zhang; et al.
Abstract: A new fragment contribution-corresponding states (FC—CS) method based on the group contribution method and the corresponding states principle is developed to predict critical properties of ionic liquids (ILs). There are 46 fragments specially classified for ILs considering the ionic features of ILs, and the corresponding fragment increments are determined using the experimental density data. The accuracy of the developed method is verified indirectly via predicting density and surface tension of ILs. The results show that the FC—CS method is reasonable with an average absolute relative deviation less than 4%. With the calculated critical properties,corresponding states heat capacity (CSHC) and corresponding states thermal conductivity (CSTC) correlations are proposed to predict heat capacity and thermal conductivity of ILs, respectively. The predicted results agreed well with the experimental data. The proposed FC—CS method and the two corresponding states correlations are important for design, simulation, and analysis of new ionic liquid processes.
Keywords: ionic liquids; fragment contribution-corresponding states method; density; heat capacity; thermal conductivity
來源出版物:AIChE Journal, 2013, 59(4): 1348-1359
編輯:王微
CO2capture by a task-specific ionic liquid
Bates, ED; Mayton, RD; Ntai, I; et al.
Reaction of 1-butyl imidazole with 3-bromopropylamine hydrobromide, followed by workup and anion exchange, yields a new room temperature ionic liquid incorporating a cation with an appended amine group. The new ionic liquid reacts reversibly with CO2,reversibly sequestering the gas as a carbamate salt. The new ionic liquid, which can be repeatedly recycled in this role, is comparable in efficiency for CO2capture to commercial amine sequestering reagents, and yet is nonvolatile and does not require water to function.
supercritical water; D-fructose; glucose; dehydration; decomposition; catalysis; mechanism; kinetics; sucrose; biomass
摘編自《化學學報》2015年73期:310~315頁,圖、表、參考文獻已省略。