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高等教育与中国城市产业结构转型 被引量:7
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作者 余长林 孟祥旭 《教育与经济》 CSSCI 北大核心 2021年第6期20-29,共10页
基于2004—2017年中国280个城市的高等教育与城市产业结构数据,本文研究了高等教育对中国城市产业结构转型的影响。研究发现,高等教育促进了中国城市产业结构的高级化,且该影响在不同地区间存在显著差异。高等教育通过两个渠道影响城市... 基于2004—2017年中国280个城市的高等教育与城市产业结构数据,本文研究了高等教育对中国城市产业结构转型的影响。研究发现,高等教育促进了中国城市产业结构的高级化,且该影响在不同地区间存在显著差异。高等教育通过两个渠道影响城市的产业结构转型:一是从供给侧来看,高等教育通过提高城市的创新能力促进城市产业结构转型升级;二是从需求侧来看,高等教育通过提高城市劳动力的收入水平推动城市需求结构转型,进而促进城市产业结构的转型升级。通过这两个渠道,高等教育可以从供给侧和需求侧同时推动城市产业结构的高级化,且这一作用会受到人口跨区域流动的影响。通过解决内生性问题和替代核心解释变量的检验结果表明,本文的估计结果依然稳健。本研究对城市的人才引进政策和高质量发展具有一定的政策启示。 展开更多
关键词 高等教育 人力资本 创新 产业结构
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异质/同质相结高效光催化的研究进展:以相变构建为例(英文) 被引量:7
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作者 杨凯 李笑笑 +4 位作者 曾德彬 陈范云 余长林 张开莲 黄微雅 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第6期796-818,共23页
半导体光催化剂在环境处理和能量转换方面有着巨大的应用潜力,但由于电子-空穴对的复合作用,半导体光催化剂的光催化性能较低.相结的存在是提高电子-空穴分离效率及光催化活性的有效途径,对相结设计的深入研究是提高电荷转移性能和效率... 半导体光催化剂在环境处理和能量转换方面有着巨大的应用潜力,但由于电子-空穴对的复合作用,半导体光催化剂的光催化性能较低.相结的存在是提高电子-空穴分离效率及光催化活性的有效途径,对相结设计的深入研究是提高电荷转移性能和效率的有效手段.因此,相结光催化技术的发展,对于设计一个良好的相结和了解电子-空穴分离机理具有重要的意义.通常,相结的构建需要特殊的制备技术以及良好的晶格匹配.纳米异质结材料结合快速转移载流子的特点,具有小尺寸效应和颗粒限域效应的优点,且具有单组分纳米材料或体相异质结不具有的独特特性.纳米晶异质结可以促进光生电子的快速转移,根据两种半导体带的相对位置,异质结可分为I型、II型和III型,根据不同的电子转移途径可分为p-n型和Z-型.当p型半导体(空穴为多数电荷载流子)或n型半导体(电子为多数电荷载流子)密切接触时,由于能带和其它性质的差异,会形成结,并在结的两侧形成空间电位差.空间电位差的存在可以使产生光生载流子从一个半导体能级注入到另一个半导体能级,从而促进电子和空穴的分离,提高光催化效率.以p-n结为例,当它们在这两个区域共存时,它们的边界层形成一个薄的p-n结.由于p型区空穴浓度高, n型区电子浓度高,结处存在电子和空穴的扩散现象.在p-n结边界附近形成空间电荷区,从而在结内形成强的局域电场.在结的局部电场作用下,电荷在结两端累积形成电位差,后者作为驱动力可以有效地分离光生电荷.近年来,人们在纳米相结的设计和制备上做了大量工作以提高光催化剂活性.虽然异质结具有优良的性能,但异质结的成分和元素并不是单一的,它的形成也不是一步反应.首先,需要分别合成异质结的两个成分,反应复杂,耗时,不环保.与异质结相比,同一材料通过相变构建的结也能实现光生载流子的高效分离.同质化不需要引入其它要素,因此引起了大量关注.在相变过程中,大多数均由不同晶相的半导体形成,如锐钛矿型/金红石型TiO_2,α-β相Ga_2O_3或六方/立方Cd S.由于化学成分相同,半导体材料的能带结构不易改变.因此,对同晶材料的同质结研究较少.虽然已有几篇关于异质相结的综述论文,但通过对外部诱导相变法制备相结的回顾,仍可为读者提供有关该领域研究进展的新的认识.本文对低成本、高效率的相变思路在光催化领域中的应用进行了简要的总结,并对其在光催化领域中的应用前景进行了展望. 展开更多
关键词 相变 相结 光催化 有效电子转移
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复合微量NCQDs对提高Ag_2CO_3半导体降解苯酚的光催化性能研究(英文) 被引量:7
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作者 田坚 刘仁月 +2 位作者 刘珍 余长林 刘敏超 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第12期1999-2008,共10页
半导体光催化具有无毒、无污染、低能耗等优点,广泛应用于水溶液中染料、药物分子的降解等.其中Ag_2CO_3半导体因其较窄的带隙能和显著的可见光吸收性能而引起广泛关注.但是Ag_2CO_3在光照下极不稳定.目前,主要是通过引入其它半导体等... 半导体光催化具有无毒、无污染、低能耗等优点,广泛应用于水溶液中染料、药物分子的降解等.其中Ag_2CO_3半导体因其较窄的带隙能和显著的可见光吸收性能而引起广泛关注.但是Ag_2CO_3在光照下极不稳定.目前,主要是通过引入其它半导体等材料与其进行复合来提其催化活性与稳定性.本文以一种具有良好的水溶性以及能够加快电子转移能力的碳量子点(CQDs)和氮掺杂的碳量子点(NCQDs)作为复合材料,利用简单的沉淀法制备出了CQDs/Ag_2CO_3、NCQDs/Ag_2CO_3等复合材料.结果表明,CQDs和NCQDs的存在能够很好的提升光催化性能.而且发现NCQDs除了具有碳量子点的特性外,还能够诱导电荷离域,更加有效的促进电子的转移.利用X射线衍射、扫描电镜、透射电镜、N_2物理吸附、元素成像、紫外-可见光漫反射吸收光谱、红外光谱以及光电流和交流阻抗测试等手段对所制备的CQDs/Ag_2CO_3和NCQDs/Ag_2CO_3进行了表征.结果表明,量子点的存在能够有效增大Ag_2CO_3的比表面积.紫外-可见漫反射吸收结果说明,量子点的存在还能够在一定程度上增大样品的可见光吸收性能.而光电流和交流阻抗测试结果证明,量子点的存在能显著降低载流子的迁移阻力,提高光生电子与空穴的分离效率.在量子点相同含量下,NCQDs能够更加有效的转移载流子.以350 W氙灯加可见光滤光片(λ≥420 nm)作为光源进行光催化降解苯酚的性能测试.结果表明,NCQDs/Ag_2CO_3比CQDs/Ag_2CO_3表现出更高的活性,其对苯酚的降解率约为后者的2倍;同时NCQDs/Ag_2CO_3还具有更佳的稳定性能.自由基捕获试验说明,在光催化过程中,主要的活性物种为?OH与?O_2^-.NCQDs能够提高Ag_2CO_3活性与稳定性的原因在于,NCQDs能够提高了催化剂的比表面积,增强光催化剂的光吸收性能.另外NCQDs能够比CQDs更有效的转移电子,提高光生e^-和h^+的分离效率,产生更多的光催化降解活性物种. 展开更多
关键词 Ag2CO3 氮掺杂碳量子点 光催化 活性与稳定性 苯酚
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离子交换法制备廉价而高效的可见光驱动CaMg(CO_3)_2@Ag_2CO_3微球光催化剂(英文) 被引量:4
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作者 田坚 吴榛 +5 位作者 刘珍 余长林 杨凯 朱丽华 黄微雅 周阳 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第11期1899-1908,共10页
Ag_2CO_3是一种典型的银基半导体,可在可见光照射下降解各种有机染料,但制备成本高,光腐蚀严重,稳定性差,难以循环利用等,因而限制了它的实际应用.针对这些问题,目前多数的改进措施是构建异质结,有效的分离光生电子与空穴来提高Ag_2CO_... Ag_2CO_3是一种典型的银基半导体,可在可见光照射下降解各种有机染料,但制备成本高,光腐蚀严重,稳定性差,难以循环利用等,因而限制了它的实际应用.针对这些问题,目前多数的改进措施是构建异质结,有效的分离光生电子与空穴来提高Ag_2CO_3的光催化性能.比如典型的异质结光催化剂有TiO_2/Ag_2CO_3,Ag_2CO_3/Zn O,Ag_2O/Ag_2CO_3和Ag X/Ag_2CO_3等.也有在表面化学沉积,光化学还原Ag等贵金属形成等离子体等方式提高其光催化性能,但是很少通过特殊形貌控制以提高Ag_2CO_3的光催化性能.最近的研究表明,由于多尺度微球结构催化剂具有高效的光捕能力,同时具有比表面积大、易沉降,良好的物质传输能力和表面的渗透性,因而在液相光催化反应中具有明显的优势.因此,我们期望制备出一个多尺度微球结构Ag_2CO_3光催化剂.CaMg(CO_3)_2是一种具有微球结构的半导体,它与Ag_2CO_3有相同的阴离子结构,但是两者在水溶液中的溶解度相差较大,利用这个特性理论上可以将两个不同的半导体结合在一起,得到一种新型的复合微球.本文以CaMg(CO_3)_2微球为硬模板,通过简单的离子交换成功制备了粒径约为10mm的CaMg(CO_3)_2@Ag_2CO_3微球.利用X射线衍射、N_2物理吸附、扫描电镜、傅里叶变换红外光谱和紫外-可见漫反射吸收光谱、光电流等手段对在不同反应时间与温度下制得的CaMg(CO_3)_2与Ag_2CO_3的复合物进行了表征.结果表明,在40°C下Ag^+与Ca^(2+)、Mg^(2+)离子交换4 h后,得到了一种多尺度CaMg(CO_3)_2@Ag_2CO_3复合微球.此时,微球中Ag_2CO_3的含量约为2.56%.结果表明,这种具有多尺度结构的复合微球能够增强可见光的吸收.电化学阻抗测试和光电流测试表明,CaMg(CO_3)_2核的存在可以降低光生载流子的迁移阻力,进而促进光生电子与空穴的分离.在光降解酸性橙II的测试中,核壳结构的CaMg(CO_3)_2@Ag_2CO_3复合微球表现出了更高的催化活性,而且具有更好的循环使用性能.同时,相对于纯Ag_2CO_3光催化剂来说,CaMg(CO_3)_2@Ag_2CO_3复合微球制备的成本大幅度降低.ESR测试证明了?OH为CaMg(CO_3)_2@Ag_2CO_3复合微球光催化过程中的主要活性物质. 展开更多
关键词 硬模板 离子交换 CaMg(CO3)2@Ag2CO3复合微球 光催化性能
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SiO2修饰强化BiOCl纳米片对有机污染物的光催化降解性能(英文) 被引量:14
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作者 余长林 何洪波 +2 位作者 刘兴强 曾巨澜 刘珍 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第8期1212-1221,共10页
许多有机污染即使在很低浓度下也可对水生生物造成各种不利影响.例如,作为合成环氧树脂和聚碳酸酯重要原料的双酚A是一种典型的内分泌干扰化学物质,当大量的双酚A被排放到水环境中时,必将对水生生态环境造成不可修复的破环.光催化技术... 许多有机污染即使在很低浓度下也可对水生生物造成各种不利影响.例如,作为合成环氧树脂和聚碳酸酯重要原料的双酚A是一种典型的内分泌干扰化学物质,当大量的双酚A被排放到水环境中时,必将对水生生态环境造成不可修复的破环.光催化技术具有催化效率高、矿化能力强和环境友好等优点,是很有应用前景的有机污染物降解方法.但是,目前大多数光催化剂尚难以满足实际有机废水处理或其它环境净化的需求.限制光催化剂大规模应用的原因可归结于以下两方面:一是光催化反应中的量子效率较低,大部分光生电子和空穴被复合而消耗掉,这使得电子和空穴很难迁移到催化剂表面及与吸附的目标降解物发生氧化反应;二是太阳光利用效率较低,在光催化剂体系中,宽带隙的半导体占有很大比重,而宽带隙的光催化剂需要短波长的紫外光来激发电子跃迁,这极大限制了自然太阳光或人工可见光的使用.BiOCl是一种绿色、稳定的新型光催化剂,具有材料易得、制备方法简单和形貌可控等诸多优点.为了进一步提高BiOCl光催化剂对有机污染物的降解活性,本文从提高量子效率的角度出发,采用SiO2纳米粒子修饰BiOCl纳米片光催化剂,以期提高光生电子和空穴分离效率,进而增强BiOCl纳米片对有机污染物的光催化降解活性.我们首先采用水解法制备了SiO2纳米粒子,然后通过水热反应制备了SiO2纳米粒子修饰的BiOCl复合光催化剂.利用XRD, FT-IR, SEM/TEM,BET, UV-vis DRS, XPS和光电流等表征手段分析了样品的物理化学性质.催化活性测试表明, SiO2/BiOCl在苯酚、双酚A和罗丹明B等有机污染物的光催化降解中表现出优越的光催化活性和稳定性.与单纯的BiOCl相比, 1.88%SiO2/BiOCl样品对罗丹明B、双酚A和苯酚的降解率分别提高了16.5%, 29.0%和38.7%.SiO2纳米粒子修饰使催化性能提升的主要原因如下:首先, SiO2的修饰增加了复合材料的比表面积,增强了污染物的吸附能力,为污染物降解提供了更多的活性位点;其次,适当的SiO2耦合有利于(110)晶面生长,高暴露的特殊晶面为电子迁移提供了更加高速的通道,从而提高了电子和空穴的分离效率;最后,光生电子可以通过紧密接触的SiO2/BiOCl界面转移到SiO2表面, SiO2表面的缺陷和空位能有效捕获光生电子,从而减小了光生载流子的复合几率,使更多的光生电子和空穴参与到光催化降解反应,进而提高了SiO2/BiOCl复合材料的光催化活性. 展开更多
关键词 SiO2/BiOCl 纳米片 有机污染物 光催化 界面
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光热协同催化去除挥发性有机化合物和CO的研究进展 被引量:13
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作者 魏龙福 余长林 +2 位作者 杨凯 樊启哲 纪红兵 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第7期1078-1095,共18页
随着社会和经济的快速发展,环境污染和能源短缺等问题,尤其是空气污染,已经影响了人类的可持续发展.挥发性有机化合物(VOCs),如苯、甲苯、甲醛和丙酮是主要的空气污染物,它们主要来源于油漆、有机化学品、石油化工产品、药物和工业生产... 随着社会和经济的快速发展,环境污染和能源短缺等问题,尤其是空气污染,已经影响了人类的可持续发展.挥发性有机化合物(VOCs),如苯、甲苯、甲醛和丙酮是主要的空气污染物,它们主要来源于油漆、有机化学品、石油化工产品、药物和工业生产过程.大多VOCs具有特殊的气味,而且具有一定的毒性、致畸性和致癌作用,尤其是苯、甲苯和甲醛等,会对人类的身体健康产生巨大的负面作用.因此,研发新型高效VOCs处理技术迫在眉睫.除VOCs外,CO也是非常常见的空气污染物,在室温条件下,它无色无味,没有刺激性且易燃易爆.CO主要来源于煤和石油等含碳材料的不完全燃烧.在日常生活中很容易被排放到大气中.在室温下,CO分子是非常稳定的,很难与其它气体分子发生化学反应.因此,CO的活化和转化是一项具有挑战性的工作.催化氧化技术是在催化剂存在的条件下进行的氧化反应,可以将VOCs直接氧化成为无毒无害的CO_(2)和H_(2)O,也可将CO氧化成CO_(2).光催化技术是一种新型的环境友好型技术,可在常温常压下进行,反应条件温和、能耗小、操作简单,成本低,氧化产物为无毒无害物质,以及不存在二次污染等优点.但光催化反应效率较低,主要通过入射光的能量驱动化学反应.热催化则通过升温的方法来驱动化学反应.目前,热催化剂主要为贵金属型催化剂,其具有催化活性较高,选择性较好且不存在二次污染等优点.但高能耗影响产物的稳定性和选择性,此外,贵金属的使用导致成本增加.光热协同催化可以整合光催化和热催化的优势,并弥补各自的不足,形成一种协同效应,是一种新颖的催化反应.目前,关于光催化或热催化高效去除VOCs和CO的综述较多,但很少有关于光热协同催化高效去除VOCs和CO的综述.本综述重点讨论光热协同催化高效去除VOCs和CO的最新研究进展.首先,介绍了光热协同催化的概况,如设计光热催化材料和催化反应器等.其次,重点介绍苯、甲苯、乙醇、甲醛、乙醛和丙酮等几种典型VOCs的光热协同催化的最新研究进展.再次,总结了光热协同催化CO加氢和氧化的最新研究进展.此外,还探讨了光热协同催化去除VOCs和CO的可能反应机理.最后,对光热协同催化的应用前景进行了展望. 展开更多
关键词 挥发性有机化合物 CO 光催化 热催化 光热协同催化
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Additive effects of alkaline-earth metals and nickel on the performance of Co/γ-Al_2O_3 in methane catalytic partial oxidation 被引量:8
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作者 changlin yu Weizheng Weng +4 位作者 Qing Shu Xiangjie Meng Bin Zhang Xirong Chen Xiaochun Zhou 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第2期135-139,共5页
Nano-sized γ-alumina (γ-Al2O3) was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel (Ni) with different contents were loaded on the... Nano-sized γ-alumina (γ-Al2O3) was first prepared by a precipitation method. Then, active component of cobalt and a series of alkaline- earth metal promoters or nickel (Ni) with different contents were loaded on the γ-Al2O3 support. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD) and thermogravimetry analysis (TGA). The activity and selectivity of the catalysts in catalytic partial oxidation (CPO) of methane have been compared with Co/γ-Al2O3, and it is found that the catalytic activity, selectivity, and stability are enhanced by the addition of alkaline-earth metals and nickel. The optimal loadings of strontium (Sr) and Ni were 6 and 4 wt%, respectively. This finding will be helpful in designing the trimetallic Co-Ni-Sr/γ-Al2O3 catalysts with high performance in CPO of methane. 展开更多
关键词 AL2O3 催化部分氧化 碱土金属 镍钴 加性效应 甲烷 性能 活性成分
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Controlled preparation of P-doped g-C3N4 nanosheets for efficient photocatalytic hydrogen production 被引量:6
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作者 Qiachun Lin Zesheng Li +4 位作者 Tingjian Lin Bolin Li Xichun Liao Huiqing yu changlin yu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第10期2677-2688,共12页
Hydrogen production by photolysis of water by sunlight is an environmentally-friendly preparation technology for renewable energy.Graphitic carbon nitride(g-C3N4),despite with obvious catalytic effect,is still unsatis... Hydrogen production by photolysis of water by sunlight is an environmentally-friendly preparation technology for renewable energy.Graphitic carbon nitride(g-C3N4),despite with obvious catalytic effect,is still unsatisfactory for hydrogen production.In this work,phosphorus element is incorporated to tune g-C3N4's property through calcinating the mixture of g-C3N4 and Na H2PO2,sacrificial agent and co-catalyst also been supplied to help efficient photocatalytic hydrogen production.Phosphorus(P)doped g-C3N4 samples(PCN-S)were prepared,and their catalytic properties were studied.X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and ultraviolet diffuse reflection(UV-DRS)were used to study their structures and morphologies.The results show that the reaction rate of PCN-S is 318μmol·h^-1·g^-1,which is 2.98 times as high as pure carbon nitride nanosheets(CN)can do.Our study paves a new avenue,which is simple,environment-friendly and sustainable,to synthesize highly efficient P doping g-C3N4 nanosheets for solar energy conversion. 展开更多
关键词 Graphitic carbon nitride P-DOPING Carbon defect Pt co-catalyst Hydrogen evolution
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基于尖晶石型混合金属钴矿的高效析氧电催化性能 被引量:3
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作者 陶磊明 郭鹏虎 +5 位作者 朱伟玲 李天乐 周贤太 傅永庆 余长林 纪红兵 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第12期1855-1863,共9页
尖晶石钴矿(例如ACo2O4,其中A=Mn,Fe,Co,Ni,Cu或Zn的阳离子取代)是一种精确调控其电子结构/性质,并因此改善相应的电催化水分解析氧(OER)性能的有前途的策略.然而,有关它的基本原理和机制尚未完全理解.为了确定尖晶石氧化物在OER中的作... 尖晶石钴矿(例如ACo2O4,其中A=Mn,Fe,Co,Ni,Cu或Zn的阳离子取代)是一种精确调控其电子结构/性质,并因此改善相应的电催化水分解析氧(OER)性能的有前途的策略.然而,有关它的基本原理和机制尚未完全理解.为了确定尖晶石氧化物在OER中的作用,已有实验和理论报道.例如,Prabu发现Ni^3+离子取代NiCo2O4的八面体位点可以显着提高OER性能;Hutchings报道OER性能提高源自Co3O4八面体Co^3+的活性位;Wei研究发现MnCo2O4八面体位置的Mn^3+离子是OER的活性位点.尽管多数研究没有对此给出清晰的解释,但这些研究清楚地表明,尖晶石氧化物对OER的电催化性能在很大程度上取决于过渡金属阳离子(A)的化合价态及其在尖晶石结构中的相应位点分布.本文旨在合成具有同种形貌的尖晶石ACo2O4混合金属有机骨架(MMOFs)材料,通过A位引入外层d电子数从5到10的过渡金属元素,如Mn,Fe,Co,Ni,Cu和Zn,系统研究催化水分解析氧机理.基于实验详细分析了不同阳离子的取代和其OER的催化行为,在获得的六种尖晶石ACo2O4催化剂中,FeCo2O4催化剂在碱性溶液中具有出色的OER性能和稳定性,其在电流密度10 mA·cm^-2的超电势下164 mV.催化剂的电荷传输性能与离子和空位扩散的跳跃率密切相关.我们使用密度泛函理论计算阳离子在ACo2O4晶体中的扩散以及扩散的活化能,并且计算过程考虑自旋的激发能.使用VASP的搜索过渡态方法(NEB-DMTS)确定离子扩散的最小能量反应路径.结果表明,尖晶石钴矿ACo2O4晶格中的Fe取代可以显著加速电荷转移,从而获得增强的电化学性能.由第一性原理计算Fe阳离子通过四面体-三角平面-八面体路径扩散,具有0.4 eV的活化能和0.5 eV的能量以形成八面体中间体.当它跳跃时,阳离子(Fe)分别在过渡态和四面体鞍点(亚稳态)下从+1.82的Bader电荷增加到+2.82和+2.83的电荷,这表明扩散的Fe在不同的位置具有的相应的价态.根据晶体场理论,通过八面体位置偏好能量(OSPE)是用于判断阳离子占据八面体或四面体的位置,其被定义为占据八面体和四面体的晶体场能量(CFSE)差.OSPE的顺序依次是Ni^2+>Ni^3+>Mn^2+>Co^3+>Co^2+>Fe^3+>Mn^2+>Cu^2+>Zn2,由于Fe(Ⅱ)、Co(Ⅱ)和Ni(Ⅱ)的OSPE值大于Co(Ⅲ)的OSPE值,这三种阳离子在四面体可以与八面体Co(Ⅲ)发生交换.对Fe(Ⅱ)离子,研究发现Fe(Td)←→Co(Oh)交换很容易进行,Fe既可以占据八面体又可以占据四面体,所以FeCo2O4为复合尖晶石结构,可以从ACo2O4晶体的X射线吸收光谱法获得阳离子A的价态和分布证实.更深入研究发现尖晶石ACo2O4的晶体场,不仅决定A位阳离子的价态,同时影响这些尖晶石钴矿OER性能的关键因素. 展开更多
关键词 阳离子取代的尖晶石钴矿 晶体场 氧还原反应 水分解 电催化
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溶剂热合成可调控氧空位的Bi_(2)MoO_(6)纳米晶及其光催化氧化制喹啉和抗生素降解 被引量:2
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作者 刘珍 田坚 +2 位作者 余长林 樊启哲 刘兴强 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第2期472-484,共13页
近年来,半导体光催化在环境净化和有机合成领域的研究引起了广泛的重视.其中,在有机合成领域中,光催化技术已经应用在醇类、环己烷以及芳香族化合物的选择性氧化研究.而另一类具有特殊结构的有机物——N-杂环芳烃,在药物化学和材料科学... 近年来,半导体光催化在环境净化和有机合成领域的研究引起了广泛的重视.其中,在有机合成领域中,光催化技术已经应用在醇类、环己烷以及芳香族化合物的选择性氧化研究.而另一类具有特殊结构的有机物——N-杂环芳烃,在药物化学和材料科学中具有重要意义.而传统用于合成N-杂化芳烃的脱氢催化氧化反应通常需要高温高压的苛刻环境,传统方法通常还需要使用贵金属催化剂,这也增加了N-杂化芳烃的合成成本;另外,如果合成是均相催化过程,则催化剂难以实现回收利用.因此,开发室温常压条件下的非贵金属多相光催化技术具有巨大的应用前景.本文以能够被可见光驱动的钼酸铋半导体为催化剂,利用氧缺陷策略来提升钼酸铋的光催化氧化性能.不同于传统氧缺陷制备方法(氢气还原热处理、离子掺杂等),本文采用一种低成本的乙二醛辅助溶剂热的方法合成具有可调控的含氧空位Bi_(2)MoO_(6)催化剂(OVBMO).通过X射线粉末衍射(XRD)、扫描电镜、透射电镜、紫外可见漫反射吸收光谱、氮气物理吸附脱附、X射线光电子能谱(XPS)、电子自旋共振光谱、光致发光光谱及电化学测试等技术对制备的OVBMO材料进行了物理化学性质及能带研究.XPS,XRD,Raman和FT-IR结果表明,氧空位存在于[Bi_(2)O_(2)]^(2+)和MoO_(6)八面体的层间.紫外可见漫反射结果表明,随着氧空位的引入,Bi_(2)MoO_(6)的光吸收范围扩大,带隙变窄.结合莫特肖特基和VBXPS分析获得OVBMO的能带位置,发现氧空位的存在不仅会导致禁带中出现缺陷带能级,还会导致价带顶位置上移,促进光生空穴的迁移.PL和电化学结果表明,氧空位的存在使得载流子浓度、载流子的分离能力与界面电荷迁移能力都有较大提升,这是因为氧空位引入的缺陷能级可以浅势捕获电子,抑制光催化剂中的电子与空穴的复合,改变化学反应的速率.同时,氧空位有助于捕获分子氧,分子氧与捕获的光生电子发生反应,产生更多的超氧自由基(·O_(2))和空穴(h^(+)),从而极大地提升光催化剂的氧化性能.因此,OVBMO在1,2,3,4-四氢喹啉脱氢氧化产生喹啉及系列抗生素(环丙沙星、四环素、盐酸土霉素)的降解反应中,表现出较好的光催化氧化性能.结合多种表征分析,本文还进一步阐明了OVBMO催化剂将1,2,3,4-四氢喹啉脱氢氧化为喹啉的自由基参与的多相催化反应机理. 展开更多
关键词 Bi_(2)MoO_(6)纳米晶体 氧空位 光催化氧化性能 喹啉生产 抗生素降解
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Novel Ni/CeO_2-Al_2O_3 composite catalysts synthesized by one-step citric acid complex and their performance in catalytic partial oxidation of methane 被引量:1
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作者 changlin yu Jiubiao Hu +1 位作者 Wanqin Zhou Qizhe Fan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第2期235-243,共9页
A series of novel Ni/CeO2-Al2O3composite catalysts were synthesized by one-step citric acid complex method. The as-synthesized catalysts were characterized by N2physical adsorption/desorption, X-ray diffraction(XRD), ... A series of novel Ni/CeO2-Al2O3composite catalysts were synthesized by one-step citric acid complex method. The as-synthesized catalysts were characterized by N2physical adsorption/desorption, X-ray diffraction(XRD), Fourier transform infrared(FT-IR) spectroscopy, hydrogen temperature-programmed reduction(H2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry analysis(TGA). The effects of nickel content, calcination and reaction temperatures, gas hourly space velocity(GHSV) and inert gas dilution of N2on their performance of catalytic partial oxidation of methane(CPOM) were investigated. Catalytic activity test results show that the highest methane conversion(>85%), the best selectivities to carbon monoxide(>87%) and to hydrogen(>95%), the excellent stability and perfect H2/CO ratio(2.0) can be obtained over Ni/CeO2-Al2O3with 8 wt% Ni content calcined at 700 ℃ under the reaction condition of 750 ℃, CH4/O2ratio of 2 : 1 and gas hourly space velocity of 12000 mL h-1 g-1. Characterization results show that the good catalytic performance of this composite catalyst can be contributed to its large specific surface area(~108 m2 g-1), small crystallite size, easy reducibility and low coking rate. 展开更多
关键词 复合催化剂 氧化性能 络合物 柠檬酸 一步法 合成 甲烷 X射线光电子能谱
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Three-dimensional oxygen-doped porous graphene:Sodium chloridetemplate preparation,structural characterization and supercapacitor performances
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作者 Zesheng Li Bolin Li +6 位作者 Lijun Du Weiliang Wang Xichun Liao Huiqing yu changlin yu Hongqiang Wang Qingyu Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第12期304-314,共11页
Supercapacitor is a new type of energy storage device,which has the advantages of high-power property and long cycle life.In this study,three-dimensional graphene(3 D-GN)with oxygen doping and porous structure was pre... Supercapacitor is a new type of energy storage device,which has the advantages of high-power property and long cycle life.In this study,three-dimensional graphene(3 D-GN)with oxygen doping and porous structure was prepared from graphene oxide(GO)by an inexpensive sodium chloride(NaCl)template,as a promising electrode material for the supercapacitor.The structure,morphology,specific surface area,pore size,of the sample were characterized by XRD,SEM,TEM and BET techniques.The electrochemical performances of the sample were tested by CV and CDC techniques.The 3 D-GE product is a threedimensional nano material with hierarchical porous structures,its specific surface area is much larger than that of routine stacked graphene(GN),and it contains a large number of mesoporous and macropores,a small amount of micropores.The capacitance characteristics of the 3 D-GN electrode material are excellent,showing high specific capacitance(173.5 F·g^(-1)at 1 A·g^(-1)),good rate performance(109.2 F·g^(-1)at 8 A·g^(-1))and long cycle life(88%capacitance retention after 10,000 cycles at 8 A·g^(-1)) 展开更多
关键词 3-D porous graphene Template preparation Sodium chloride SUPERCAPACITOR
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第三届华人光催化材料学术研讨会专刊前言
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作者 余家国 余长林 余火根 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第2期177-177,共1页
Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on P... Photocatalytic materials have attracted more and more attention in the world due to their great potential in solar energy conversion and environmental remediation.We were honored to host the 3rd Chinese Symposium on Photocatalytic Materials(CSPM3)in Wuhan on December 11-14,2020,and hereby express our sincere thanks to all the guests and delegates attending this conference. 展开更多
关键词 PHOTOCATALYTIC WUHAN attending
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Mismatched donor cell infusion-related syndrome following microtransplant in patients with acute myeloid leukemia
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作者 Bo Cai Xiaoyan Zou +12 位作者 Xin Ning Tieqiang Liu Bingxia Li Yaqing Lei Jianhui Qiao Kaixun Hu Yangyang Lei Zhiqing Liu Bo Yao Huisheng Ai Yi Wang changlin yu Mei Guo 《Chinese Medical Journal》 SCIE CAS CSCD 2023年第7期815-821,共7页
Background:Immunotherapies such as adoptive immune cell infusion and immune-modulating agents are widely used for cancer treatment,and the concomitant symptoms,including cytokine release syndrome(CRS)or immune-related... Background:Immunotherapies such as adoptive immune cell infusion and immune-modulating agents are widely used for cancer treatment,and the concomitant symptoms,including cytokine release syndrome(CRS)or immune-related adverse events(irAEs),are frequently reported.However,clinical manifestations induced by mismatched donor granulocyte colony-stimulating factor mobilized peripheral blood mononuclear cell(GPBMC)infusion in patients receiving microtransplant(MST)have not yet been well depicted.Methods:We analyzed 88 cycles of mismatched GPBMC infusion in patients with acute myeloid leukemia receiving MST and 54 cycles of chemotherapy without GPBMC infusion as a comparison.Clinical symptoms and their correlation with clinical features,laboratory findings,and clinical response were explored.Results:Fever(58.0%[51/88])and chills(43.2%[38/88])were the significant early-onset symptoms after GPBMC infusion.Patients possessing less human leukocyte antigen-matching loci with the donor or those with unrelated donors experienced more chills(3[2–5]loci vs.5[3–5]loci,P=0.043 and 66.7%[12/18]vs.37.1%[26/70],P=0.024).On the other hand,those with decreased CD4^(+)/CD8^(+)T-cell ratio developed more fever(0.8[0.7–1.2]vs.1.4[1.1–2.2],P=0.007).Multivariable analysis demonstrated that younger patients experienced more fever(odds ratio[OR]=0.963,95%confidence interval[CI]:0.932–0.995,P=0.022),while patients with younger donors experienced more chills(OR=0.915,95%CI:0.859–0.975,P=0.006).Elevated ultra-sensitive C-reactive protein levels in the absence of cytokine storm were observed following GPBMC infusion,which indicated mild and transient inflammatory response.Although no predictive value of infusion-related syndrome to leukemia burden change was found,the proportion of host pre-treatment activated T cells was positively correlated with leukemia control.Conclusions:Mismatched GPBMC infusion in MST induced unique infusion-related symptoms and laboratory changes,which were associated with donor-or recipient-derived risk factors,with less safety and tolerance concerns than reported CRS or irAEs. 展开更多
关键词 Microtransplant IMMUNOTHERAPY Adoptive immune cell infusion Adverse events Acute myeloid leukemia
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La/Ce-codoped Bi_2O_3 composite photocatalysts with high photocatalytic performance in removal of high concentration dye 被引量:7
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作者 Shuangshuang Xue Hongbo He +5 位作者 Qizhe Fan changlin yu Kai Yang Weiya Huang Yang Zhou yu Xie 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第10期70-77,共8页
A series of La/Ce-codoped Bi_2O_3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like ... A series of La/Ce-codoped Bi_2O_3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N_2 physical adsorption, X-ray powder diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), UV–Vis diffuse reflectance(UV–Vis DRS), Fourier transform infrared spectroscopy(FT-IR),photoelectrochemical measurements, and photoluminescence(PL) spectroscopy. The characterization results indicated that La and Ce doping induced obvious crystal phase transformation in Bi_2O_3, from monoclinic to tetragonal phase. La and Ce codoping also gave rise to the obvious synergetic effects, e.g., the lattice contraction of Bi_2O_3, the decrease of crystal size and the increase of surface area. The photocatalytic performance of the prepared catalysts was evaluated by removal of dye acid orange II with high concentration under visible light irradiation. Results showed that La/Ce-codoped Bi_2O_3 displayed much higher photocatalytic performance than that of bare Bi_2O_3, single La or Ce doped Bi_2O_3 samples. The superior photocatalytic activity was mainly attributed to the improved texture and surface properties and the synergistic effects of La and Ce codoping on suppressing the recombination of photo-generated electrons(e^-) and holes(h^+). 展开更多
关键词 复合光催化剂 BI2O3 光催化性能 酸性染料 铈掺杂 浓度 扫描电子显微镜 去除率
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A Lamellar Ceria Structure with Encapsulated Platinum Nanoparticles 被引量:5
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作者 Angelo C.Mak changlin yu +2 位作者 Jimmy C.yu Zhendong Zhang Chunman Ho 《Nano Research》 SCIE EI CSCD 2008年第6期474-482,共9页
A novel lamellar feather-like CeO_(2) structure has been fabricated by using a triblock copolymer as the structure-directing agent.This material was characterized in detail by X-ray diffraction,scanning electron micro... A novel lamellar feather-like CeO_(2) structure has been fabricated by using a triblock copolymer as the structure-directing agent.This material was characterized in detail by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,and BET surface area measurements.Compared with conventional spherical shaped ceria prepared by ammonia gelation,the ceria feathers have superior ability to support nanosized platinum particles due to their special structure.The“skeletons”of ceria feathers can serve as an ideal host matrix to anchor the platinum particles.Furthermore,the inter-crossing pattern of the“skeletons”also acts as a partition to separate platinum particles,allowing the Pt nanoparticles(average diameter~6 nm)to be highly dispersed in the structure.The Pt/feather-like CeO_(2) catalyst exhibits high activity in the water gas shift reaction. 展开更多
关键词 CERIA NANOSTRUCTURE PLATINUM nanoparticles surfactant-controlled synthesis water gas shift reaction
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Experimental and mechanistic understanding of photo-oxidation of methanol catalyzed by CuO/TiO2-spindle nanocomposite:Oxygen vacancy engineering 被引量:3
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作者 Quanquan Shi Zhaoxian Qin +5 位作者 changlin yu Ammara Waheed Hui Xu Yong Gao Hadi Abroshan Gao Li 《Nano Research》 SCIE EI CAS CSCD 2020年第4期939-946,共8页
We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%s... We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%selectivity.The catalysts are obtained via precise depositing of CuO nanoclusters(size:~3.5 nm)at the{101}facet of the TiO2 to optimally tune exciton recombination through oxygen vacancies generation,evidenced by photoluminescence and Raman spectroscopy measurements.The turnover frequency(TOF)and the apparent quantum efficiency(AQE)of the 7%CuO/TiO2-spindle composites reach up to 23.8 molmethanol·gcat^-1·h^-1 and 55.2%at 25℃,respectively,which are substantially higher than these previously reported photocatalysts.Further,the in-situ attenuated total reflection infrared spectroscopy analysis reveals that the methanol oxidation most likely takes place through the conversion of adsorbed methoxy(CH30^*)to formaldehyde(CHO^*)intermediate,a subject of major debate for a long time.The adsorbed formaldehyde(CHO^*)thus produced reacts with another CH30^*species in its close proximity to form the final product of methyl formate.Results of this study provide insights into the reaction mechanism,and offer guidelines to systematically develop and apply photocatalysts for methanol conversion and related reactions via surface engineering. 展开更多
关键词 CuO/Ti02 nanocomposite methyl formate in-situ attenuated total reflection infrared spectroscopy photocatalysis oxygen vacancy METHANOL
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High value-added fluorescence upconversion agents-assisted nanosemiconductors for efficient wide spectral response photocatalysis:Exerting energy transfer effect and applications 被引量:1
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作者 Kailian Zhang Man Zhou +7 位作者 changlin yu Xiaoxiao Li Kai Yang Shi Yang Wenxin Dai Weiya Huang Qizhe Fan Lihua Zhu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2021年第3期243-260,I0001,共19页
The design of the photocatalytic materials has made a great of remarkable progress in the area of the enhancement photocatalytic activity,but there are still lots of problems such as wide band gap,low utilization of s... The design of the photocatalytic materials has made a great of remarkable progress in the area of the enhancement photocatalytic activity,but there are still lots of problems such as wide band gap,low utilization of sunlight,low quantum efficiency and poor stability,which further limit the extensive practical applications.Thus,it is a hot research topic and key scientific problem to be solved that how to design and prepare the catalysts,which can respond to visible and near-infrared light in sunlight.Inspired by efficient nonlinear optical upconversion materials,upconversion-based nanocomposites can indirectly broaden the absorption ranges of semiconductors by co nverting the captured long-band visible and near-infrared incident light into high-energy short-band visible or ultraviolet light,which can be adopted as the promising candidate in wide-spectral-light-activating photocatalytic materials coupling with conventional semiconductors.According to our recent works and literature reports,recent review summarizes the research progress of photocatalytic materials with upconversion effect on photolysis of water for hydrogen production,degradation of organic and inorganic pollutants,reduction of CO_(2) and photodynamic therapy.The prepared nanocomposites can suppress the recombination of electrons and holes,and greatly improve the photocatalytic efficiency by the synergistic effect.It maybe stimulates a great interest in rational design and preparation of efficient full-spectrum photocatalytic systems and their wide application in solar energy conversion. 展开更多
关键词 Fluorescence upconversion Hydrogen production PHOTOCATALYSIS Treatment of pollutants Photodynamic therapy Rare earths
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