本文主要研究内容
作者梁志琴（2019）在《新型纳米材料在电催化二氧化碳还原和上转换发光中的应用》一文中研究指出：本论文基于一系列新型纳米材料在电催化CO2还原和上转换发光中的应用展开研究。在电催化CO2还原方面,随着全球人口数量的急剧增加和经济的快速发展,人类社会对能源的需求越来越大,而化石燃料作为主要能量来源,其过度消耗造成了 CO2等温室气体排放,引起严重的全球变暖,因此能源危机与环境污染已成为21世纪全世界所面临的严峻挑战。采用电催化方法将CO2还原为具有更高利用价值的化学物质和燃料则既能解决巨大的能源需求问题,又能缓解高浓度C02带来的全球气候变暖,从而完成自然界中碳资源的循环利用。同时反应中所需的电力资源可来自于太阳能、风能或者潮汐能等可再生利用资源,这使得该转化过程更加环保、高效和安全。Cu基材料是目前被证实的能够将CO2电化学还原为多碳产物的最有效的催化剂,因此,相比其他金属材料更为引人注目。如何设计合理的催化剂和反应体系以使CO2还原针对特定产物达到最高的选择性、活性和稳定性,仍然是目前研究工作中需要解决并进一步优化的关键科学问题。本课题旨在开展一系列铜基纳米催化剂的设计及其电催化CO2还原性能研究。通过制备不同组分的铜基化合物,表征其反应过程中催化剂的结构、形貌和组分变化,同时结合DFT理论计算对特定产物的产生路径进行设计和分析,并在H-cell和Flow-cell两种体系中进行电还原反应探究,最终实现CO2的高效转化。取得研究成果如下:1.提出了 Flow-cell体系使氧化物还原的Cu高效还原CO为多碳产物。以C02还原为多碳产物中公认的中间体*CO作为反应源,在Flow-cell体系中采用气相扩散传输电极,该电极结构为多孔性,且两侧均疏水。CO气体通入电极一侧,而电解液通过反应泵进入载有催化剂的电极另一侧,形成气-液-固三相反应界面,从而解决了传统的液-固两相界面反应造成的CO气体在水相电解液中质量传输受限问题。最终在电还原条件下,氧化物还原的Cu催化剂进行CO还原得到法拉第效率为85%的C2+产物。2.设计了基于Cu基硫化物的核-壳催化剂来调控CO2还原反应产物选择性。采用高温溶剂热法,利用合成过程中控制Cu源和S源的非化学计量比以及原位电化学还原过程分别在催化剂表面引入空位(V)和形成Cu2S/Cu核-壳结构,结合DFT理论计算发现,所设计的Cu2S/Cu-V催化剂在形成C2H4和C2H5OH的路径中,在最后一个共有的中间体*CH2CHO加氢过程中,相比于Cu2S/Cu催化剂和Cu-V催化剂而言,能够通过提高C2H4形成时的活化能量势垒,使得反应向醇类产生方向进行。最终,在H-cell和Flow-cell体系中分别得到法拉第效率为23%和32%的C2+醇类产生,其C2+醇类分电流密度分别为7.3 mA cm-2和126 mA cm-2该反应活性在目前关于CO2还原产生多碳醇类中的报道中为最高值3.构筑了采用金属氮化物支撑表面Cu催化剂的复合结构来实现CO2还原的稳定性。通过对Cu3N纳米颗粒配体交换进行部分氧化和随后的原位电还原两个步骤实现了 Cu-on-Cu3N催化剂的制备。为了研究Cu3N支撑体对于表面Cu催化剂的影响,同时制备了 Cu-on-Cu2O和纯Cu催化剂。通过原位X射线吸收(XAS)技术实时监测反应过程中组分变化,对于Cu-on-Cu3N催化剂,在反应1小时后Cu和Cu3N都存在于催化剂中,而且组分逐渐稳定;但对于Cu-on-Cu2O催化剂,反应40分钟后Cu2O已经全部被还原,催化剂成为Cu2O还原的Cu。同时结合高分辨透射电子能量损失光谱面扫(HRTEM-EELS mapping)技术和角分辨X射线光电子能谱(ARXPS)对催化剂反应前后的形貌和电子结构进行表征,进一步证明了Cu3N支撑物对于反应过程中稳定催化剂中Cu0和Cu+组分的重要性,从而实现CO2还原产生64%的C2+产物,并在连续32小时反应中性能没有明显减弱。最后,DFT进一步对反应过程中*CO聚合时的能量势垒进行计算,结果表明,Cu on-Cu3N具有最低的能量势垒,再次证明了该催化剂在CO2还原过程中的优越性在上转换发光方面,上转换发光纳米材料可以吸收多个低能量光子而发射出高能量光子,由于这种材料特性对生物组织损伤较低,且低能量的红外光对生物组织的穿透能力强,不会激发生物体发光,所以目前上转换发光纳米材料在生物检测和细胞成像等方面具有重要的应用价值。然而,如何对上转换发光纳米材料进行设计和修饰以提高其发光效率,对在生物医学应用中具有重要的影响意义本课题研究了新型NaYF4纳米材料的上转换发光性能。在经典的NaYF4基质材料中掺杂低浓度K+,以改变发光中心Er3+周围的晶体场环境,提高4f禁带跃迁几率,实现发光性能的优化。同时,采用Li+和K+双掺杂对NaYF4:Yb,Er材料体系进一步优化,相比于未掺杂的样品,实现了绿光和红光强度分别增强7倍和10倍,随后将其应用于体外生物免疫层析检测,结果表明,这种纳米颗粒的双靶向检测具有很高的灵敏度。此外,还探索了非NaYF4的Sc基上转换发光基质,发现LiScF4在掺杂敏化剂Yb和激活剂Er时,也可实现高强度的上转换荧光发射,且相比于具有绿光发射的NaYF4基质而言,LiScF4更能促进其蓝光和红光发射。
Abstract
ben lun wen ji yu yi ji lie xin xing na mi cai liao zai dian cui hua CO2hai yuan he shang zhuai huan fa guang zhong de ying yong zhan kai yan jiu 。zai dian cui hua CO2hai yuan fang mian ,sui zhao quan qiu ren kou shu liang de ji ju zeng jia he jing ji de kuai su fa zhan ,ren lei she hui dui neng yuan de xu qiu yue lai yue da ,er hua dan ran liao zuo wei zhu yao neng liang lai yuan ,ji guo du xiao hao zao cheng le CO2deng wen shi qi ti pai fang ,yin qi yan chong de quan qiu bian nuan ,yin ci neng yuan wei ji yu huan jing wu ran yi cheng wei 21shi ji quan shi jie suo mian lin de yan jun tiao zhan 。cai yong dian cui hua fang fa jiang CO2hai yuan wei ju you geng gao li yong jia zhi de hua xue wu zhi he ran liao ze ji neng jie jue ju da de neng yuan xu qiu wen ti ,you neng huan jie gao nong du C02dai lai de quan qiu qi hou bian nuan ,cong er wan cheng zi ran jie zhong tan zi yuan de xun huan li yong 。tong shi fan ying zhong suo xu de dian li zi yuan ke lai zi yu tai yang neng 、feng neng huo zhe chao xi neng deng ke zai sheng li yong zi yuan ,zhe shi de gai zhuai hua guo cheng geng jia huan bao 、gao xiao he an quan 。Cuji cai liao shi mu qian bei zheng shi de neng gou jiang CO2dian hua xue hai yuan wei duo tan chan wu de zui you xiao de cui hua ji ,yin ci ,xiang bi ji ta jin shu cai liao geng wei yin ren zhu mu 。ru he she ji ge li de cui hua ji he fan ying ti ji yi shi CO2hai yuan zhen dui te ding chan wu da dao zui gao de shua ze xing 、huo xing he wen ding xing ,reng ran shi mu qian yan jiu gong zuo zhong xu yao jie jue bing jin yi bu you hua de guan jian ke xue wen ti 。ben ke ti zhi zai kai zhan yi ji lie tong ji na mi cui hua ji de she ji ji ji dian cui hua CO2hai yuan xing neng yan jiu 。tong guo zhi bei bu tong zu fen de tong ji hua ge wu ,biao zheng ji fan ying guo cheng zhong cui hua ji de jie gou 、xing mao he zu fen bian hua ,tong shi jie ge DFTli lun ji suan dui te ding chan wu de chan sheng lu jing jin hang she ji he fen xi ,bing zai H-cellhe Flow-cellliang chong ti ji zhong jin hang dian hai yuan fan ying tan jiu ,zui zhong shi xian CO2de gao xiao zhuai hua 。qu de yan jiu cheng guo ru xia :1.di chu le Flow-cellti ji shi yang hua wu hai yuan de Cugao xiao hai yuan COwei duo tan chan wu 。yi C02hai yuan wei duo tan chan wu zhong gong ren de zhong jian ti *COzuo wei fan ying yuan ,zai Flow-cellti ji zhong cai yong qi xiang kuo san chuan shu dian ji ,gai dian ji jie gou wei duo kong xing ,ju liang ce jun shu shui 。COqi ti tong ru dian ji yi ce ,er dian jie ye tong guo fan ying beng jin ru zai you cui hua ji de dian ji ling yi ce ,xing cheng qi -ye -gu san xiang fan ying jie mian ,cong er jie jue le chuan tong de ye -gu liang xiang jie mian fan ying zao cheng de COqi ti zai shui xiang dian jie ye zhong zhi liang chuan shu shou xian wen ti 。zui zhong zai dian hai yuan tiao jian xia ,yang hua wu hai yuan de Cucui hua ji jin hang COhai yuan de dao fa la di xiao lv wei 85%de C2+chan wu 。2.she ji le ji yu Cuji liu hua wu de he -ke cui hua ji lai diao kong CO2hai yuan fan ying chan wu shua ze xing 。cai yong gao wen rong ji re fa ,li yong ge cheng guo cheng zhong kong zhi Cuyuan he Syuan de fei hua xue ji liang bi yi ji yuan wei dian hua xue hai yuan guo cheng fen bie zai cui hua ji biao mian yin ru kong wei (V)he xing cheng Cu2S/Cuhe -ke jie gou ,jie ge DFTli lun ji suan fa xian ,suo she ji de Cu2S/Cu-Vcui hua ji zai xing cheng C2H4he C2H5OHde lu jing zhong ,zai zui hou yi ge gong you de zhong jian ti *CH2CHOjia qing guo cheng zhong ,xiang bi yu Cu2S/Cucui hua ji he Cu-Vcui hua ji er yan ,neng gou tong guo di gao C2H4xing cheng shi de huo hua neng liang shi lei ,shi de fan ying xiang chun lei chan sheng fang xiang jin hang 。zui zhong ,zai H-cellhe Flow-cellti ji zhong fen bie de dao fa la di xiao lv wei 23%he 32%de C2+chun lei chan sheng ,ji C2+chun lei fen dian liu mi du fen bie wei 7.3 mA cm-2he 126 mA cm-2gai fan ying huo xing zai mu qian guan yu CO2hai yuan chan sheng duo tan chun lei zhong de bao dao zhong wei zui gao zhi 3.gou zhu le cai yong jin shu dan hua wu zhi cheng biao mian Cucui hua ji de fu ge jie gou lai shi xian CO2hai yuan de wen ding xing 。tong guo dui Cu3Nna mi ke li pei ti jiao huan jin hang bu fen yang hua he sui hou de yuan wei dian hai yuan liang ge bu zhou shi xian le Cu-on-Cu3Ncui hua ji de zhi bei 。wei le yan jiu Cu3Nzhi cheng ti dui yu biao mian Cucui hua ji de ying xiang ,tong shi zhi bei le Cu-on-Cu2Ohe chun Cucui hua ji 。tong guo yuan wei Xshe xian xi shou (XAS)ji shu shi shi jian ce fan ying guo cheng zhong zu fen bian hua ,dui yu Cu-on-Cu3Ncui hua ji ,zai fan ying 1xiao shi hou Cuhe Cu3Ndou cun zai yu cui hua ji zhong ,er ju zu fen zhu jian wen ding ;dan dui yu Cu-on-Cu2Ocui hua ji ,fan ying 40fen zhong hou Cu2Oyi jing quan bu bei hai yuan ,cui hua ji cheng wei Cu2Ohai yuan de Cu。tong shi jie ge gao fen bian tou she dian zi neng liang sun shi guang pu mian sao (HRTEM-EELS mapping)ji shu he jiao fen bian Xshe xian guang dian zi neng pu (ARXPS)dui cui hua ji fan ying qian hou de xing mao he dian zi jie gou jin hang biao zheng ,jin yi bu zheng ming le Cu3Nzhi cheng wu dui yu fan ying guo cheng zhong wen ding cui hua ji zhong Cu0he Cu+zu fen de chong yao xing ,cong er shi xian CO2hai yuan chan sheng 64%de C2+chan wu ,bing zai lian xu 32xiao shi fan ying zhong xing neng mei you ming xian jian ruo 。zui hou ,DFTjin yi bu dui fan ying guo cheng zhong *COju ge shi de neng liang shi lei jin hang ji suan ,jie guo biao ming ,Cu on-Cu3Nju you zui di de neng liang shi lei ,zai ci zheng ming le gai cui hua ji zai CO2hai yuan guo cheng zhong de you yue xing zai shang zhuai huan fa guang fang mian ,shang zhuai huan fa guang na mi cai liao ke yi xi shou duo ge di neng liang guang zi er fa she chu gao neng liang guang zi ,you yu zhe chong cai liao te xing dui sheng wu zu zhi sun shang jiao di ,ju di neng liang de gong wai guang dui sheng wu zu zhi de chuan tou neng li jiang ,bu hui ji fa sheng wu ti fa guang ,suo yi mu qian shang zhuai huan fa guang na mi cai liao zai sheng wu jian ce he xi bao cheng xiang deng fang mian ju you chong yao de ying yong jia zhi 。ran er ,ru he dui shang zhuai huan fa guang na mi cai liao jin hang she ji he xiu shi yi di gao ji fa guang xiao lv ,dui zai sheng wu yi xue ying yong zhong ju you chong yao de ying xiang yi yi ben ke ti yan jiu le xin xing NaYF4na mi cai liao de shang zhuai huan fa guang xing neng 。zai jing dian de NaYF4ji zhi cai liao zhong can za di nong du K+,yi gai bian fa guang zhong xin Er3+zhou wei de jing ti chang huan jing ,di gao 4fjin dai yue qian ji lv ,shi xian fa guang xing neng de you hua 。tong shi ,cai yong Li+he K+shuang can za dui NaYF4:Yb,Ercai liao ti ji jin yi bu you hua ,xiang bi yu wei can za de yang pin ,shi xian le lu guang he gong guang jiang du fen bie zeng jiang 7bei he 10bei ,sui hou jiang ji ying yong yu ti wai sheng wu mian yi ceng xi jian ce ,jie guo biao ming ,zhe chong na mi ke li de shuang ba xiang jian ce ju you hen gao de ling min du 。ci wai ,hai tan suo le fei NaYF4de Scji shang zhuai huan fa guang ji zhi ,fa xian LiScF4zai can za min hua ji Ybhe ji huo ji Ershi ,ye ke shi xian gao jiang du de shang zhuai huan ying guang fa she ,ju xiang bi yu ju you lu guang fa she de NaYF4ji zhi er yan ,LiScF4geng neng cu jin ji lan guang he gong guang fa she 。
论文参考文献
论文详细介绍
论文作者分别是来自北京交通大学的梁志琴，发表于刊物北京交通大学2019-09-27论文，是一篇关于电催化论文,二氧化碳还原论文,铜基纳米催化剂论文,氧化亚铜论文,硫化亚铜论文,氮化亚铜论文,上转换发光论文,四氟钇钠论文,四氟钪锂论文,北京交通大学2019-09-27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，资料来自北京交通大学2019-09-27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：电催化论文; 二氧化碳还原论文; 铜基纳米催化剂论文; 氧化亚铜论文; 硫化亚铜论文; 氮化亚铜论文; 上转换发光论文; 四氟钇钠论文; 四氟钪锂论文; 北京交通大学2019-09-27论文;