Synthesis of Axially Coordinated Cobalt Porphyrin/graphene Oxide Nanocomposite for Enhanced Electrocatalytic CO2 Reduction to CO

The electrocatalysts containing cobalt-pyrrolic nitrogen-carbon （Co-N₄-C） moiety for CO₂ reduction reaction （CO₂RR） have caught much attention.However,the effects of Co valence state and its synergy with graphene substrate are not clear yet.In this work,cobalt porphyrin （Co TPP） molecule with the intrinsic Co-N₄-C moiety is successfully combined with graphene oxide （GO） via three kinds of liquid-phase methods.The ratio of Co TPP to GO and the valence s...     

Synthesis, Characterization of Heterodinuclear Co-Cu Complex and Its Electrocatalytic Activity towards O_2 Reduction: Implications for Cytochrome c Oxidase Active Site Modeling

IntroductionMetalloenzymesplaymanyimportantrolesinnatureespeciallyinelectron transferbiologicalprocesses .Be causeoftheirimportanceandcomplexity ,manysimplifiedmodelsystemshavebeenconstructedforthestudyoftheirchemistry .Amongvariouspolymetallicmetalloenzymes ,cytochromecoxidase (CcO)istheoneofthemostspecialinterest.CcO ,theterminalenzymeoftherespiratorychain ,catalyzesthereductionofO2 by 4H+,4e- towaterwith outleakageofanypartiallyreducedintermediateswhicharetoxictocellsuchasH2 O2 .Thefree…     

Axial Ligand Coordination Tuning of the Electrocatalytic Activity of Iron Porphyrin Electrografted onto Carbon Nanotubes for the Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) is essential in many life processes and energy conversion systems. It is desirable to design transition metal molecular catalysts inspired by enzymatic oxygen activation/reduction processes as an alternative to noble-metal-Pt-based ORR electrocatalysts, especially in view point of fuel cell commercialization. We have fabricated bio-inspired molecular catalysts electrografted onto multiwalled carbon nanotubes (MWCNTs) in which 5,10,15,20-tetra(pentafluorophenyl) iron porphyrin (iron porphyrin FeF₂₀TPP) is coordinated with covalently electrografted axial ligands varying from thiophene to imidazole on the MWCNTs’ surface. The catalysts’ electrocatalytic activity varied with the axial coordination environment (i. e., S-thiophene, N-imidazole, and O-carboxylate); the imidazole-coordinated catalyst MWCNTs-Im-FeF₂₀TPP exhibited the highest ORR activity among the prepared catalysts. When MWCNT-Im-FeF₂₀TPP was loaded onto the cathode of a zinc−air battery, an open-cell voltage (OCV) of 1.35 V and a maximum power density (P_max) of 110 mW cm⁻² were achieved; this was higher than those of MWCNTs-Thi-FeF₂₀TPP (OCV=1.30 V, P_max=100 mW cm⁻²) and MWCNTs-Ox-FeF₂₀TPP (OCV=1.28 V, P_max=86 mW cm⁻²) and comparable with a commercial Pt/C catalyst (OCV=1.45 V, P_max=120 mW cm⁻²) under similar experimental conditions. This study provides a time-saving method to prepare covalently immobilized molecular electrocatalysts on carbon-based materials with structure–performance correlation that is also applicable to the design of other electrografted catalysts for energy conversion.     

脉冲微波辅助化学还原合成Pt/C 催化剂及其电催化氧还原性能

采用脉冲微波辅助化学还原法制备了质子交换膜燃料电池(PEMFC)用Pt/C 催化剂. 通过透射电镜(TEM)和X射线衍射(XRD)等分析技术对催化剂的微观结构和形貌进行了表征, 并利用循环伏安(CV)、线性扫描(LSV)和恒电位测量等方法评价了催化剂催化氧还原性能. 在此基础上制备了膜电极(MEA)并组装成单电池, 考察了制备的Pt/C 催化剂作为阴极催化剂材料的电催化性能. 结果表明, 脉冲微波辅助化学还原法是一种制备PEMFC催化剂的有效方法, 溶液pH值和微波功率对Pt 颗粒直径和分散有重要影响. TEM和XRD结果显示, 当溶液pH值为10 且微波功率为2 kW时, Pt 纳米粒子较均匀地分散在碳载体上, 粒径分布在1.3-2.4 nm之间, 平均粒径为1.8 nm. CV、LSV和恒电位测试结果表明, 该催化剂电化学比表面积(ESA)为55.6 m²·g^-1, 具有良好的催化氧还原反应活性和稳定性. 单电池测试结果表明, 在溶液pH值为10条件下, 微波功率为2 kW时制备的催化剂作阴极催化剂时, 单电池最高功率密度为2.26 W·cm^-2·mg^-1, 高于微波功率为1 kW时的最高功率密度(2.15 W·cm^-2·mg^-1)和Johnson Matthey催化剂的最高功率密度(1.89 W·cm^-2·mg^-1).     

铁卟啉的合成及其电催化性能研究

合成了四苯基卟啉及其铁衍生物,用红外光谱进行了结构表征。采用光电子能谱(XPS)方法研究了热处理对铁卟啉结构的影响,通过测定空气电极极化曲线研究了热处理对铁卟啉的催化活性和稳定性的影响。结果表明,铁卟啉具有良好的氧气还原催化活性。热处理提高了铁卟啉的催化活性和稳定性,600℃下热处理的铁卟啉催化活性最好,800℃热处理的铁卟啉的稳定性最好。     

Synthesis and Characterization of the Host-Guest NanocompositeMaterial Zeolite Y-Iron Bipyridine

Zeoliteshavethedefinedcrystallinestructureswiththechannelsorcagesofnanoscaledimensions.Thesechannelsorcagesofzeolitescanoffertheloadingsitestoselfassembleandstabilizetheentrappedguestwithinthezeolitesthatcanbeusedforusefulmatrixestoproducenanoguestsmaterialsl.Becausethiskindofmaterialsshowedsomespecialproperty=,ithasarousedmuchinterest3.Anewfieldofinvestigationfortheentrappedmetalcomplexeshasbeendevelopedinelectro-assistedcatalysisoforganicreaction'.Atpresent,therearethreeapproachestotheprepar…     

二氧化钛与碳化钨纳米复合材料制备及其对甲醇的电催化氧化活性

以市售纳米二氧化钛(TiO2)为载体,六氯化钨为钨源,将浸渍法与原位还原碳化技术相结合制备了核壳结构碳化钨(WC)/TiO2纳米复合材料;应用X射线衍射分析、透射电子显微镜、高分辨扫描透射成像和X射线能量散射谱等手段对样品晶相、形貌、微结构和化学组成等特征进行了表征.结果表明,样品的晶相由金红石型TiO2、Ti4O7、WC、W2C和WxC构成,钨碳化物负载于钛氧化物外表面,构成比较典型的核壳结构.采用三电极体系和循环伏安法测试了样品在碱性溶液中对甲醇的电催化氧化活性,结果表明,相比于纯碳化钨和二氧化钛,复合材料的电催化活性得到了明显的提升.样品电催化活性的提升与前驱体钨钛摩尔比、还原碳化时间、核壳结构壳层的完整性和晶相组成以及核壳结构中二氧化钛和碳化钨之间的协同效应有关.这说明金红石是能够提升碳化钨电催化氧化活性的载体材料之一.     

Investigation of Light-harvest Material： Synthesis and Characterization of Nanometer Porphyrin Trimer

ω-Bromopropylporphyrin ether synthesized from the raction of 1,3-dibromopropane as the bridge-linkedreagent and 5- (4-hydroxyphenyl)-10,15,20-triphenylporphyrin (H2MHTPP) as the matrix reacts with 5, 15-di(4- hydroxyphenyl)-10, 20-diphenyl porphyrin(trans-H2DHDPP) to give the title nanometer porphyrintrimer. The characterization was carried out by means of elemental analyses, UV-Vis, IR, ^1H NMR andXRD.     

氮掺杂石墨烯的制备及其对氧还原反应的电催化性能

以氧化石墨烯(GO)为原料、丙酮肟(DMKO)为还原剂和氮掺杂剂,采用化学还原法制备了不同氮掺杂含量的石墨烯(NG).利用场发射透射电子显微镜(FETEM)、紫外-可见(UV-Vis)光谱、傅里叶变换红外(FTIR)光谱、X射线光电子能谱(XPS)、zeta电位和纳米粒度分析、循环伏安(CV)和旋转圆盘电极(RDE)等手段对材料的形貌、结构、成分和电化学性质进行表征.结果显示:DMKO能有效地还原GO,且通过调节GO与DMKO的质量比,可以得到不同还原效果的NG,其氮含量范围为4.40%-5.89%(原子分数);GO与DMKO的质量比为1:0.7时制备的氮掺杂石墨烯(NG-1)在O2饱和0.1 mol·L-1KOH溶液中对氧还原反应(ORR)的电催化性能最佳,其ORR峰电流为0.93 mA·cm-2,电子转移数为3.6,这归因于其较高含量的吡啶-N增加了材料的ORR活性位点.此外,石墨化-N由于其较高的电子导电性倾向于产生较高的氧还原峰电流,而吡啶-N较低的超电势倾向于产生较正的氧还原峰电位.与商用Pt/C相比,该材料展现出了优异的抗CH3OH"跨界效应"的特性.     

氮掺杂石墨烯的制备及其对氧还原反应的电催化性能

以氧化石墨烯（GO）为原料、丙酮肟（DMKO）为还原剂和氮掺杂剂,采用化学还原法制备了不同氮掺杂含量的石墨烯（NG）. 利用场发射透射电子显微镜（FETEM）、紫外-可见（UV-Vis）光谱、傅里叶变换红外（FTIR）光谱、X射线光电子能谱（XPS）、zeta 电位和纳米粒度分析、循环伏安（CV）和旋转圆盘电极（RDE）等手段对材料的形貌、结构、成分和电化学性质进行表征. 结果显示：DMKO能有效地还原GO,且通过调节GO与DMKO的质量比,可以得到不同还原效果的NG,其氮含量范围为4.40%-5.89%（原子分数）;GO与DMKO的质量比为1：0.7时制备的氮掺杂石墨烯（NG-1）在O₂饱和0.1 mol·L^-1 KOH溶液中对氧还原反应（ORR）的电催化性能最佳,其ORR峰电流为0.93 mA·cm^-2,电子转移数为3.6,这归因于其较高含量的吡啶-N增加了材料的ORR活性位点. 此外,石墨化-N由于其较高的电子导电性倾向于产生较高的氧还原峰电流,而吡啶-N较低的超电势倾向于产生较正的氧还原峰电位. 与商用Pt/C相比,该材料展现出了优异的抗CH₃OH“跨界效应”的特性.     

钴卟啉的合成及其对氧还原的电催化性能

 合成了四苯基卟啉及其钴配合物,考察了催化剂、溶剂及反应温度等因素对四苯基卟啉收率的影响,并用红外光谱和核磁共振氢谱对合成产物进行了结构表征. 以X射线光电子能谱为主要手段,研究了不同热处理温度对钴卟啉结构的影响,通过测定空气电极极化曲线研究了热处理对钴卟啉催化活性的影响. 结果表明,在200 ℃, 以对硝基苯甲酸为催化剂,硝基苯为溶剂时,四苯基卟啉收率达32%. 热处理能提高金属卟啉的催化活性, 600 ℃热处理后,钴卟啉环中的 Co-N4 结构趋于键断裂的临界状态,催化活性点增多,催化活性较好; 而800 ℃处理的钴卟啉中部分 Co-N4 键破裂,催化活性下降.     

WC/天然沸石纳米复合材料的制备与电催化活性

以天然沸石为载体,偏钨酸铵为钨源,将机械化学法与原位还原碳化技术结合,制备了碳化钨与天然沸石的纳米复合材料.制备过程中,首先对天然沸石进行预处理,然后按硅钨摩尔比为2:1配置偏钨酸铵与沸石混合物,经机械球磨得到三氧化钨与沸石复合前驱体,再将前驱体在管式炉内1173K温度下,在CH4与H2混合气氛中还原碳化即得碳化钨与沸石的纳米复合材料.采用X射线衍射(XRD)、扫描电子显微镜(SEM)和X射线能量散射谱(EDS)分别对样品的晶相、形貌、微结构和化学组成进行了表征.结果表明,样品主要由一碳化钨、碳化二钨、石英、丝光沸石、斜发沸石等物相组成.其中,一碳化钨晶粒约为30nm,碳化二钨的晶粒约为20nm.应用粉末微电极测试了样品在中性溶液中对对硝基苯酚的电催化活性.结果表明,在中性溶液中样品对对硝基苯酚电催化活性优于介孔空心球状碳化钨,样品的电还原催化活性与其WC的质量分数和WC与W2C的质量比相关.碳化钨与沸石构成复合材料后,两者具有明显的协同效应.     

水溶性卟啉配合物的合成及光敏化行为

在低沸点的氯仿溶剂中合成了中-四(对二甲基丙磺酸基氨基)苯基卟啉(简记为H₂TPS),在乙酸溶剂中合成了相应的金属卟啉[简记为MeTPS,Me=Zn(Ⅱ),Cu(Ⅱ),Ni(Ⅱ),Co(Ⅲ),Mn(Ⅱ)],并进行了表征。TEOA-MeTPS-MV²⁺-DMSO(H₂O)(75:25,V/V)体系的光敏化还原MV²⁺反应的研究结果表明,Zn(Ⅱ)TPS、Mn(Ⅱ)TPS及H₂TPS是较好的光敏剂,且以Zn(Ⅱ)TPS为最好。     

Synthesis and Characterization of a Novel Phenol‐tailed Porphyrin Ligand and Its Iron(III) Complex

The phenol‐tailed porphyrin ligand, H₃L was synthesized as a model compound for catalases. H₃L and its corresponding iron complex [Fe(L)] were synthesized by using the precursor, 5‐(8‐ethoxycarbonyl‐1‐naphthyl)‐10, 15, 20‐triphenyl porphyrin (ENTPP). They were characterized by ¹H NMR spectroscopy, mass spectrometry, X‐ray crystallography, and cyclic voltammetry. All the results have confirmed that the phenol group is covalently attached to the porphyrin. In the iron complex, phenolate oxygen is coordinated to iron(III) as the fifth ligand, leading to the five‐coordinate high‐spin iron(III) species.     

氮掺杂石墨烯的制备及氧还原电催化性能

采用两步热解法, 用尿素掺杂氧化石墨烯(GO)得到N掺杂的还原氧化石墨烯(N-RGO), 通过控制反应温度, 制备了具有不同电催化活性的N掺杂的还原氧化石墨烯. 透射电子显微镜(TEM)和扫描电子显微镜(SEM)结果显示, 制得的氮掺杂石墨烯(nG)表面褶皱和重叠增加. X射线光电子能谱(XPS)证明, 氮元素以吡啶N、 吡咯N和石墨化的N 3种形式掺杂在石墨烯中, 最高摩尔分数为6.6%. 通过循环伏安(CV)和旋转圆盘电极(RDE)测试了nG的电化学性能, 结果表明, 在酸性电解质中对氧还原(ORR)有较高的催化活性, 起始电位在0.1 V左右, 电催化还原氧气时主要为四电子反应, 且相对商用的Pt/C催化剂有更好的电化学稳定性, 其中第一步热解温度为200℃制得的nG催化性能最好.     

L-谷氨酸桥联的卟啉二联体的合成和表征及其CD光谱研究

通过L-谷氨酸(乙酰基保护)与二氯亚砜反应制备的二酰氯和单羟基卟啉(M-PH₂)反应,合成了L-谷氨酸桥联的卟啉二联体,用红外光谱、 电子吸收光谱、 核磁共振氢谱、 元素分析和质谱对化合物的结构加以确证,通过圆二色谱(CD)研究了化合物的手性特征.     

氮掺杂有序介孔碳-Ni纳米复合材料的制备及电化学性能

以F127为模板剂,Ni Cl2为镍源,尿素为氮源,间苯二酚甲醛原位聚合树脂为碳源,分别采用均相法和两相法制备Ni-NOMC-1,Ni-N-OMC-2纳米复合材料。X射线衍射(XRD)、激光拉曼以及透射电子显微镜(TEM)等测试结果表明,复合材料具有有序介孔结构,Ni以金属微粒形式嵌于碳骨架中,提高了有序介孔碳的石墨化程度。X射线光电子能谱测试(XPS)表明尿素热解后以4种形式存在:sp3杂化与C结合的N原子,吡啶N原子,sp2杂化与C结合的N原子以及quaternary-N原子。Ni-N的共改性改变了碳载体的理化性质,有利于Pt纳米粒子的负载与分散。均相法制备的Ni-N-OMC-1复合材料微波负载Pt后,氧还原极限电流密度为5.32 m A·cm-2,氢氧化电化学活性面积高达138.53 m2·g-1,电化学催化活性优于商业20%Pt/C材料(4.49 m A·cm-2,96.98 m2·g-1)。     

Synthesis and Characterization of Polyester-Based Nanocomposite

Recently, unsaturated polyester resin (UPR) and silica nanocomposite prepared by mechanical process is the one of the promising composite materials. In this study, the effects of silica as filler on mechanical, thermal, and morphological properties of unsaturated polyester-based composite were investigated. Mechanical properties such as tensile strength, elongation and Young's modulus increase with the addition of silica nanoparticle up to 1.0 wt%, and then decrease, over 1.0 wt%. Morphological surface of composite reveals that well-dispersed silica in the matrix occurred in low concentration. However, increasing of silica concentration causes aggregation of particles. Enhancement of mechanical properties strongly corresponds to strong adhession force of silica with the matrix and it influnced by well-disperse silica particles on the whole surface of composite. Thermal characterization and analysis of major functional group of the composites were also performed and described in this paper.     

氮掺杂有序介孔碳-Ni纳米复合材料的制备及电化学性能

以F₁₂₇为模板剂,NiCl₂为镍源,尿素为氮源,间苯二酚甲醛原位聚合树脂为碳源,分别采用均相法和两相法制备Ni-N-OMC-1,Ni-N-OMC-2纳米复合材料.X射线衍射(XRD)、激光拉曼以及透射电子显微镜(TEM)等测试结果表明,复合材料具有有序介孔结构,Ni以金属微粒形式嵌于碳骨架中,提高了有序介孔碳的石墨化程度.X射线光电子能谱测试(XPS)表明尿素热解后以4种形式存在:sp³杂化与C结合的N原子,吡啶N原子,sp²杂化与C结合的N原子以及quaternary-N原子.Ni-N的共改性改变了碳载体的理化性质,有利于Pt纳米粒子的负载与分散.均相法制备的Ni-N-OMC-1复合材料微波负载Pt后,氧还原极限电流密度为5.32mA·cm^-2,氢氧化电化学活性面积高达138.53m²·g^-1,电化学催化活性优于商业20%Pt/C材料(4.49mA·cm^-2,96.98m²·g^-1).     

组氨酸修饰的卟啉类化合物的合成与表征

通过吡咯和相应的醛合成了五个新型的以组氨酸修饰的卟啉类化合物．其反应条件得到优化,并通过紫外、质谱和核磁确证了产物的结构．