本文主要研究内容
作者王敏(2019)在《TiO2/石墨烯复合物界面调控与N/S掺杂改性研究》一文中研究指出:四方对称的锐钛矿TiO2具有稳定的物理化学性质,且具无毒性、价格低廉、储量丰富等优势,广泛应用于降解有机污染物、光催化水分解、电催化、太阳能电池等领域。锐钛矿TiO2的导带主要是Ti的3d态构成,价带顶部主要来源于O的2p态,带隙宽度Eg约为3.2 eV。因此,激发电子-空穴对需要光子能量hv≥3.2 eV或波长λ≤387 nm,意味着TiO2响应的波长范围在紫外光区域,少于太阳辐射总能量的5%,较低的太阳光利用率限制了TiO2的实际应用。同时,TiO2中光生电子-空穴对复合的时间间隔大约在10~100 ns,远快于它们被捕获和转移所需的时间(100 ns~1 ms),导致大部分载流子在迁移到催化剂表面之前就复合而消失,致使催化降解性能降低。因此,如何抑制载流子复合成为亟待解决的问题。另外,纳米光催化剂颗粒小,而小粒子一般具有高比表面积,因此纳米光催化剂具有更多的催化活性位置,这对提高光催化效率有利。但小粒子在溶液中容易形成悬浊液,在水净化处理后难以沉降和分离,仍残留在水中,造成二次污染。催化剂的再回收利用问题也是具有挑战性的工作。为了解决上述问题,科研人员已经在TiO2以及TiO2基复合物的合成、改性以及应用等方面做了很多研究,得出了很多有意义的研究成果。但是对于TiO2基复合物来说,其光催化反应是一个非常复杂的过程,影响光催化活性的参数很多,以往的研究报道也有很多相互矛盾、相互冲突的结论,仍存在很多亟待解决的难点问题,如在合成TiO2基复合物时,如何实现两相间的紧密接触问题:其光催化反应机理问题等。在蒸汽热反应过程中醇类的醚化反应可以为Ti4+前驱体提供水解所需的水,具有水解速率可控的特点。本论文利用该特点做了以下的研究,主要研究内容如下:1.TiO2/石墨烯复合物的蒸汽热合成与光催化性质研究。对于TiO2/石墨烯复合物来说,实现两相之间的紧密接触仍然是一个巨大的挑战。在这项工作中,使用自主开发的蒸汽热法,以钛酸异丙酯为钛源,分别在异丙醇和去离子水蒸汽环境中合成了TiO2/石墨烯复合物。对于异丙醇蒸汽环境中合成的样品,SEM/TEM结果显示TiO2呈纳米片形貌,均匀且紧密地生长于石墨烯上:XRD和FT-IR结果表明TiO2的晶格发生畸变,进一步证明了两相间的紧密接触。从价带XPS的结果中观察到晶格畸变导致TiO2的价带态密度发生变化。UV-vis DRS、BET、PL的结果表明,石墨烯与TiO2结合显著增强可见光吸收、增加比表面积、抑制光生载流子复合,进而提高光催化降解性能。ESR结果表明,·OH自由基对光催化降解的贡献更大。对于去离子水蒸汽环境中合成的样品,TiO2呈粒子形貌,散乱分布于石墨烯上,形貌特征与以往文献报道的结果相似。没有观察到TiO2的晶格畸变。石墨烯与TiO2结合增强了可见光吸收,并促进了光生载流子分离,然而比表面积却减小,光催化性能没有得到提高。这些结果表明,两相间紧密接触是实现石墨烯与TiO2协同增强效应的先决条件,而适当的合成方法至关重要。这种合成方法为进一步提高光催化性能铺平了道路,并提供了发现新性能的机会。2.TiO2/石墨烯复合物蒸汽热合成与N掺杂研究。首先在异丙醇蒸汽环境中合成纳米片状TiO2/石墨烯两相紧密接触的复合物,然后进行不同N/Ti摩尔比掺杂。掺杂N元素有以下几种存在状态:TiO2晶格间隙中、替代TiO2中的O元素、替代石墨烯中的C元素以及吸附于石墨烯和TiO2粒子表面。N掺杂效应归纳如下:N掺杂使得TiO2纳米片变成纳米粒子,伴随着复合物的比表面积减小;TiO2晶粒大小随掺杂量增加先增加后减小;N掺杂导致Ti-O-Ti振动模发生改变;N掺杂对TiO2中Ti和O元素的化学态产生影响,引入多种缺陷或杂质能级。这些因素的协同效应对光催化性能产生影响。仅当N/Ti摩尔比为2时,对亚甲基蓝的光催化降解性能有所增强,降解速率从7.7×10-2min-1(未掺N样品)提高到9.6×10-2min-1。分析ESR的结果得出,光生电子被缺陷和杂质俘获,光生空穴对光催化降解起主要作用。3.TiO2/石墨烯复合物蒸汽热合成与S掺杂研究。首先在异丙醇的蒸汽环境中,利用多元醇的醚化反应提供Ti源水解所需的水,合成TiO2/石墨烯复合物,实现TiO2与石墨烯两相间紧密接触,且二氧化钛呈纳米厚度的片状形貌。然后,用硫脲作为S源,改变S/Ti摩尔比RS/Ti,利用蒸汽热法在水蒸汽环境中对TiO2/石墨烯复合物进行不同程度S掺杂,制得系列S掺杂TiO2/石墨烯复合物,并用XRD、TEM、FT-IR、XPS、UV-vis DRS、PL、BET、ESR等手段进行系统表征,研究了S掺杂对光催化降解性能的影响。观察到依赖S掺杂程度的形貌、化学态、晶体结构、电子结构以及光催化性能的变化。主要结论如下:(1)S掺杂使TiO2纳米片变为纳米粒子。(2)掺杂的S元素以S2-、S、S4+、S6+四种化学态存在,并对TiO2晶格中Ti和O元素化学态产生影响。Rs/Ti=0.5时,仅有单质S存在,没有出现替位S元素。RS/Ti≥1时,出现S2-替代O2-,S4+/S6+替代Ti4+。(3)S掺杂在TiO2价带顶以上引入电子态。(4)TiO2晶体结构产生畸变,RS/Ti=3时晶格应变最大。(5)S掺杂使TiO2对污染物亚甲基蓝(MB)的降解速率由7.7×10-2min-1增加到10.7×10-2min-1,相应的样品具有最高数量的·OH和·O2-自由基,且·OH对降解起着更主要的作用。4.CoFe2/CoFe2O4/TiO2合成与光催化性质研究。这项工作的目的是研究磁芯材料与催化剂之间界面对光催化机理的影响。CoFe2合金在所有二元合金中具有最高的磁化强度,有利于磁分离。首先,制备均匀分散的CoFe2O4纳米粒子,并利用金属有机盐热分解法包覆MgO。通过在H2/N2混合气体中还原,再在空气中氧化,完成从CoFe2O4/MgO到CoFe2/MgO,再到CoFe2/CoFe2O4/MgO的结构转变。其中MgO可以通过稀盐酸溶液酸洗。接下来,包覆TiO2使CoFe2O4,CoFe2/MgO,CoFe2和CoFe2/CoFe2O4磁性粒子的表面功能化,研究了它们的磁性、光催化性能、可分离循环性和温度效应。在没有模板和蚀刻剂的帮助下获得了具有摇铃结构的磁芯/TiO2壳的纳米颗粒。这些光催化剂在亚甲基蓝(MB)降解中的光催化活性实验表明,不同催化剂表面负载TiO2能力不同,光催化性能不同,具有纳米片状TiO2和摇铃结构的磁芯/TiO2壳的纳米颗粒表现出良好的光催化性能。CoFe2/TiO2样品具有93%的最佳降解效率,因为CoFe2芯可以捕获TiO2中的光生电子,抑制电子和空穴对的复合;同时具有最高的饱和磁化强度值42 emu/g,对光催化剂使用后的回收有利。除了光催化应用之外,这些强磁性颗粒易于被外部磁场驱动,在其他领域也可以发挥作用,如细胞分离和靶向给药等。
Abstract
si fang dui chen de rui tai kuang TiO2ju you wen ding de wu li hua xue xing zhi ,ju ju mo du xing 、jia ge di lian 、chu liang feng fu deng you shi ,an fan ying yong yu jiang jie you ji wu ran wu 、guang cui hua shui fen jie 、dian cui hua 、tai yang neng dian chi deng ling yu 。rui tai kuang TiO2de dao dai zhu yao shi Tide 3dtai gou cheng ,jia dai ding bu zhu yao lai yuan yu Ode 2ptai ,dai xi kuan du Egyao wei 3.2 eV。yin ci ,ji fa dian zi -kong xue dui xu yao guang zi neng liang hv≥3.2 eVhuo bo chang λ≤387 nm,yi wei zhao TiO2xiang ying de bo chang fan wei zai zi wai guang ou yu ,shao yu tai yang fu she zong neng liang de 5%,jiao di de tai yang guang li yong lv xian zhi le TiO2de shi ji ying yong 。tong shi ,TiO2zhong guang sheng dian zi -kong xue dui fu ge de shi jian jian ge da yao zai 10~100 ns,yuan kuai yu ta men bei bu huo he zhuai yi suo xu de shi jian (100 ns~1 ms),dao zhi da bu fen zai liu zi zai qian yi dao cui hua ji biao mian zhi qian jiu fu ge er xiao shi ,zhi shi cui hua jiang jie xing neng jiang di 。yin ci ,ru he yi zhi zai liu zi fu ge cheng wei ji dai jie jue de wen ti 。ling wai ,na mi guang cui hua ji ke li xiao ,er xiao li zi yi ban ju you gao bi biao mian ji ,yin ci na mi guang cui hua ji ju you geng duo de cui hua huo xing wei zhi ,zhe dui di gao guang cui hua xiao lv you li 。dan xiao li zi zai rong ye zhong rong yi xing cheng xuan zhuo ye ,zai shui jing hua chu li hou nan yi chen jiang he fen li ,reng can liu zai shui zhong ,zao cheng er ci wu ran 。cui hua ji de zai hui shou li yong wen ti ye shi ju you tiao zhan xing de gong zuo 。wei le jie jue shang shu wen ti ,ke yan ren yuan yi jing zai TiO2yi ji TiO2ji fu ge wu de ge cheng 、gai xing yi ji ying yong deng fang mian zuo le hen duo yan jiu ,de chu le hen duo you yi yi de yan jiu cheng guo 。dan shi dui yu TiO2ji fu ge wu lai shui ,ji guang cui hua fan ying shi yi ge fei chang fu za de guo cheng ,ying xiang guang cui hua huo xing de can shu hen duo ,yi wang de yan jiu bao dao ye you hen duo xiang hu mao dun 、xiang hu chong tu de jie lun ,reng cun zai hen duo ji dai jie jue de nan dian wen ti ,ru zai ge cheng TiO2ji fu ge wu shi ,ru he shi xian liang xiang jian de jin mi jie chu wen ti :ji guang cui hua fan ying ji li wen ti deng 。zai zheng qi re fan ying guo cheng zhong chun lei de mi hua fan ying ke yi wei Ti4+qian qu ti di gong shui jie suo xu de shui ,ju you shui jie su lv ke kong de te dian 。ben lun wen li yong gai te dian zuo le yi xia de yan jiu ,zhu yao yan jiu nei rong ru xia :1.TiO2/dan mo xi fu ge wu de zheng qi re ge cheng yu guang cui hua xing zhi yan jiu 。dui yu TiO2/dan mo xi fu ge wu lai shui ,shi xian liang xiang zhi jian de jin mi jie chu reng ran shi yi ge ju da de tiao zhan 。zai zhe xiang gong zuo zhong ,shi yong zi zhu kai fa de zheng qi re fa ,yi tai suan yi bing zhi wei tai yuan ,fen bie zai yi bing chun he qu li zi shui zheng qi huan jing zhong ge cheng le TiO2/dan mo xi fu ge wu 。dui yu yi bing chun zheng qi huan jing zhong ge cheng de yang pin ,SEM/TEMjie guo xian shi TiO2cheng na mi pian xing mao ,jun yun ju jin mi de sheng chang yu dan mo xi shang :XRDhe FT-IRjie guo biao ming TiO2de jing ge fa sheng ji bian ,jin yi bu zheng ming le liang xiang jian de jin mi jie chu 。cong jia dai XPSde jie guo zhong guan cha dao jing ge ji bian dao zhi TiO2de jia dai tai mi du fa sheng bian hua 。UV-vis DRS、BET、PLde jie guo biao ming ,dan mo xi yu TiO2jie ge xian zhe zeng jiang ke jian guang xi shou 、zeng jia bi biao mian ji 、yi zhi guang sheng zai liu zi fu ge ,jin er di gao guang cui hua jiang jie xing neng 。ESRjie guo biao ming ,·OHzi you ji dui guang cui hua jiang jie de gong suo geng da 。dui yu qu li zi shui zheng qi huan jing zhong ge cheng de yang pin ,TiO2cheng li zi xing mao ,san luan fen bu yu dan mo xi shang ,xing mao te zheng yu yi wang wen suo bao dao de jie guo xiang shi 。mei you guan cha dao TiO2de jing ge ji bian 。dan mo xi yu TiO2jie ge zeng jiang le ke jian guang xi shou ,bing cu jin le guang sheng zai liu zi fen li ,ran er bi biao mian ji que jian xiao ,guang cui hua xing neng mei you de dao di gao 。zhe xie jie guo biao ming ,liang xiang jian jin mi jie chu shi shi xian dan mo xi yu TiO2xie tong zeng jiang xiao ying de xian jue tiao jian ,er kuo dang de ge cheng fang fa zhi guan chong yao 。zhe chong ge cheng fang fa wei jin yi bu di gao guang cui hua xing neng pu ping le dao lu ,bing di gong le fa xian xin xing neng de ji hui 。2.TiO2/dan mo xi fu ge wu zheng qi re ge cheng yu Ncan za yan jiu 。shou xian zai yi bing chun zheng qi huan jing zhong ge cheng na mi pian zhuang TiO2/dan mo xi liang xiang jin mi jie chu de fu ge wu ,ran hou jin hang bu tong N/Tima er bi can za 。can za Nyuan su you yi xia ji chong cun zai zhuang tai :TiO2jing ge jian xi zhong 、ti dai TiO2zhong de Oyuan su 、ti dai dan mo xi zhong de Cyuan su yi ji xi fu yu dan mo xi he TiO2li zi biao mian 。Ncan za xiao ying gui na ru xia :Ncan za shi de TiO2na mi pian bian cheng na mi li zi ,ban sui zhao fu ge wu de bi biao mian ji jian xiao ;TiO2jing li da xiao sui can za liang zeng jia xian zeng jia hou jian xiao ;Ncan za dao zhi Ti-O-Tizhen dong mo fa sheng gai bian ;Ncan za dui TiO2zhong Tihe Oyuan su de hua xue tai chan sheng ying xiang ,yin ru duo chong que xian huo za zhi neng ji 。zhe xie yin su de xie tong xiao ying dui guang cui hua xing neng chan sheng ying xiang 。jin dang N/Tima er bi wei 2shi ,dui ya jia ji lan de guang cui hua jiang jie xing neng you suo zeng jiang ,jiang jie su lv cong 7.7×10-2min-1(wei can Nyang pin )di gao dao 9.6×10-2min-1。fen xi ESRde jie guo de chu ,guang sheng dian zi bei que xian he za zhi fu huo ,guang sheng kong xue dui guang cui hua jiang jie qi zhu yao zuo yong 。3.TiO2/dan mo xi fu ge wu zheng qi re ge cheng yu Scan za yan jiu 。shou xian zai yi bing chun de zheng qi huan jing zhong ,li yong duo yuan chun de mi hua fan ying di gong Tiyuan shui jie suo xu de shui ,ge cheng TiO2/dan mo xi fu ge wu ,shi xian TiO2yu dan mo xi liang xiang jian jin mi jie chu ,ju er yang hua tai cheng na mi hou du de pian zhuang xing mao 。ran hou ,yong liu niao zuo wei Syuan ,gai bian S/Tima er bi RS/Ti,li yong zheng qi re fa zai shui zheng qi huan jing zhong dui TiO2/dan mo xi fu ge wu jin hang bu tong cheng du Scan za ,zhi de ji lie Scan za TiO2/dan mo xi fu ge wu ,bing yong XRD、TEM、FT-IR、XPS、UV-vis DRS、PL、BET、ESRdeng shou duan jin hang ji tong biao zheng ,yan jiu le Scan za dui guang cui hua jiang jie xing neng de ying xiang 。guan cha dao yi lai Scan za cheng du de xing mao 、hua xue tai 、jing ti jie gou 、dian zi jie gou yi ji guang cui hua xing neng de bian hua 。zhu yao jie lun ru xia :(1)Scan za shi TiO2na mi pian bian wei na mi li zi 。(2)can za de Syuan su yi S2-、S、S4+、S6+si chong hua xue tai cun zai ,bing dui TiO2jing ge zhong Tihe Oyuan su hua xue tai chan sheng ying xiang 。Rs/Ti=0.5shi ,jin you chan zhi Scun zai ,mei you chu xian ti wei Syuan su 。RS/Ti≥1shi ,chu xian S2-ti dai O2-,S4+/S6+ti dai Ti4+。(3)Scan za zai TiO2jia dai ding yi shang yin ru dian zi tai 。(4)TiO2jing ti jie gou chan sheng ji bian ,RS/Ti=3shi jing ge ying bian zui da 。(5)Scan za shi TiO2dui wu ran wu ya jia ji lan (MB)de jiang jie su lv you 7.7×10-2min-1zeng jia dao 10.7×10-2min-1,xiang ying de yang pin ju you zui gao shu liang de ·OHhe ·O2-zi you ji ,ju ·OHdui jiang jie qi zhao geng zhu yao de zuo yong 。4.CoFe2/CoFe2O4/TiO2ge cheng yu guang cui hua xing zhi yan jiu 。zhe xiang gong zuo de mu de shi yan jiu ci xin cai liao yu cui hua ji zhi jian jie mian dui guang cui hua ji li de ying xiang 。CoFe2ge jin zai suo you er yuan ge jin zhong ju you zui gao de ci hua jiang du ,you li yu ci fen li 。shou xian ,zhi bei jun yun fen san de CoFe2O4na mi li zi ,bing li yong jin shu you ji yan re fen jie fa bao fu MgO。tong guo zai H2/N2hun ge qi ti zhong hai yuan ,zai zai kong qi zhong yang hua ,wan cheng cong CoFe2O4/MgOdao CoFe2/MgO,zai dao CoFe2/CoFe2O4/MgOde jie gou zhuai bian 。ji zhong MgOke yi tong guo xi yan suan rong ye suan xi 。jie xia lai ,bao fu TiO2shi CoFe2O4,CoFe2/MgO,CoFe2he CoFe2/CoFe2O4ci xing li zi de biao mian gong neng hua ,yan jiu le ta men de ci xing 、guang cui hua xing neng 、ke fen li xun huan xing he wen du xiao ying 。zai mei you mo ban he shi ke ji de bang zhu xia huo de le ju you yao ling jie gou de ci xin /TiO2ke de na mi ke li 。zhe xie guang cui hua ji zai ya jia ji lan (MB)jiang jie zhong de guang cui hua huo xing shi yan biao ming ,bu tong cui hua ji biao mian fu zai TiO2neng li bu tong ,guang cui hua xing neng bu tong ,ju you na mi pian zhuang TiO2he yao ling jie gou de ci xin /TiO2ke de na mi ke li biao xian chu liang hao de guang cui hua xing neng 。CoFe2/TiO2yang pin ju you 93%de zui jia jiang jie xiao lv ,yin wei CoFe2xin ke yi bu huo TiO2zhong de guang sheng dian zi ,yi zhi dian zi he kong xue dui de fu ge ;tong shi ju you zui gao de bao he ci hua jiang du zhi 42 emu/g,dui guang cui hua ji shi yong hou de hui shou you li 。chu le guang cui hua ying yong zhi wai ,zhe xie jiang ci xing ke li yi yu bei wai bu ci chang qu dong ,zai ji ta ling yu ye ke yi fa hui zuo yong ,ru xi bao fen li he ba xiang gei yao deng 。
论文参考文献
论文详细介绍
论文作者分别是来自安徽大学的王敏,发表于刊物安徽大学2019-07-03论文,是一篇关于石墨烯复合物论文,界面调控论文,掺杂论文,掺杂论文,磁分离论文,安徽大学2019-07-03论文的文章。本文可供学术参考使用,各位学者可以免费参考阅读下载,文章观点不代表本站观点,资料来自安徽大学2019-07-03论文网站,若本站收录的文献无意侵犯了您的著作版权,请联系我们删除。
标签:石墨烯复合物论文; 界面调控论文; 掺杂论文; 磁分离论文; 安徽大学2019-07-03论文;