Surface and Interfacial Structure Control of Pt-Based Nanomaterials and Their Catalytic Applications

贵金属催化剂广泛应用于能源、环保、食品加工等重要化工领域。近年来的研究发现，贵金属催化剂的催化活性和选择性与催化剂的尺寸和表面结构密切相关。纳米颗粒的表面是催化反应的场所，所以研究贵金属纳米颗粒的表界面结构是近年纳米材料科学发展的核心方向。而如何提升贵金属利用率，同时维持高的催化剂活性、选择性和长的使用寿命一直是贵金属催化剂研制的核心问题。 本论文主要围绕三大方向进行研究：1）制备结构确定，尺寸均一的Pt纳米材料，研究Pt与氧化物的界面在催化反应中的协同效应。2）在结构确定，尺寸均一的Pt纳米晶体表面构建Pt-M(OH)x(M=Fe、Ni)界面，表征界面物种的精确结构，并研究Pt-M(OH)...Noble metal nanocatalysts are of vital importance in many fields of chemical, food, energy and environmental industry. The development of nanoscience in recent years demonstrated that the catalytic activity and selectivity of noble metal nanocatalysts are strongly dependent on both the size and the surface structure. As the surfaces of the nanoparticles are where the reactions take place, design a...学位：理学博士院系专业：化学化工学院_无机化学学号：2052011015367

A hydride-induced-reduction strategy for fabricating palladium-based core-shell bimetallic nanocrystals

Zheng, NF (通讯作者)One key challenge in making high-quality bimetallic nanocrystals is to prevent self-nucleation of individual metal components. We report in this work an effective seeded growth strategy that uses activated hydrogen atoms as the reducing agent to prepare core-shell bimetallic nanocrystals. In the developed method, Pd nanocrystals serve as the seed and catalyst as well to activate H-2 for the reductive deposition of Ag. The unique feature of the developed method is that the activated hydrogen atoms are confined on the surface of the Pd seeds. Consequently, the self-nucleation of Ag is effectively inhibited so that the deposition of Ag occurs only on Pd. The mechanism studies reveal that reductive growth of Ag on Pd seeds proceeds until the Pd surface is fully covered by Ag. The Ag/Pd ratio in the prepared Pd@Ag nanocrystals is readily fine-tuned by the amount of AgNO3 or H-2. The method is effective for depositing Ag on Pd nanocrystal seeds with different morphologies such as nanosheets, nanocubes, tetrahedra and nanowires. More importantly, the deposition of Ag on Pd nanowires allows preparation of flexible transparent electrode material with sheet electronic conductivity of 271 S sq(-1) at a transmittance of over 90%.MOST of China 2011CB932403 2014CB932004 NSFC of China 21131005 2133300

A nanoparticulate polyacetylene-supported Pd(Ⅱ) catalyst combining the advantages of homogeneous and heterogeneous catalysts

负载型的金属催化剂虽然分离方便,但在反应活性、选择性以及催化剂的结构表征方面均明显不如相应的均相催化剂.将均相催化剂通过不同的化学键固载于高比表面积载体是实现均相催化剂多相化的重要途径,这样可使催化剂兼具均相和多相催化剂的优势.然而要将均相催化剂锚定于特定载体上,通常涉及较为复杂的合成反应,对载体也有严格的要求.因而该法仅仅适用于实验室研究,难以实现规模生产.因此,提供一种简便有效地制备兼具均相和多相催化剂优势的催化剂合成方法非常必要.本文报道一种简便的制备聚乙炔纳米颗粒负载Pd(Ⅱ)催化剂(nP-Pd(Ⅱ))的方法,所制催化剂在水相中的SuzukI-MIyAurA偶联反应中表现出极高的活性,同时具有便于分离、容易放大制备的特点.在室温下,将乙炔气通入PdC l2-4的水溶液中迅速变得浑浊,静置后容器底部有棕色沉淀,同时溶液变为无色透明.固体产物使用水、乙醇等溶剂进行洗涤;干燥之后收集既得聚乙炔纳米颗粒负载的Pd(Ⅱ)催化剂nP-Pd(Ⅱ).使用透射电子显微镜、红外(Ir)及拉曼吸收光谱、X射线衍射(Xrd)、X射线光电子能谱(XPS)以及X射线吸收光谱(EXAfS)等手段对nP-Pd(Ⅱ)进行了详细表征.结果显示,在nP-Pd(Ⅱ)中Pd并非以Pd纳米颗粒形式存在;Xrd中没有未Pd纳米晶的特征衍射峰.Ir等表征证明乙炔在Pd的催化作用下发生聚合作用,生成了聚乙炔.EXAfS结果表明,Pd分别和氯原子以及C=C双键进行配位;同时,没有观察到Pd–Pd键的生成,进一步证明了Pd未被还原为Pd纳米颗粒.XPS也印证了Pd(Ⅱ)的价态.形貌上,nP-Pd(Ⅱ)为直径2–3nM的颗粒,其中的Pd原子均匀分散于聚乙炔纳米颗粒上,使其在反应过程中能够充分地与底物接触,从而在SuzukI-MIyAurA偶联反应中表现出极高的活性.更重要的是,由于“憎水效应“,nP-Pd(Ⅱ)在溶液中以微米级的聚集体形式存在,因而反应后通过离心或者静置从反应体系中分离出来.因此,在nP-Pd(Ⅱ)催化剂中,每个Pd原子都是潜在的活性中心,这与典型的均相催化剂相似;同时,其独特的形貌使其具备了多相催化剂便于分离的特点.因此,nP-Pd(Ⅱ)是一种兼具均相和多相催化剂优点的催化剂且其催化剂的制备方法极为简便.乙炔是常用的工业气体,溶剂采用水,制备在室温下即可完成,我们也成功地制备出克级规模的高活性、稳定性的nP-Pd(Ⅱ)催化剂.A novel nanoparticulate polyacetylene-supported Pd(Ⅱ) catalyst(NP-Pd(Ⅱ)) for use in the aqueous Suzuki-Miyaura cross coupling reaction was successfully synthesized by simply treating an aqueous solution of PdC l42- with acetylene under ambient conditions.Electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy were employed to characterize the NP-Pd(Ⅱ) structure in detail.These analyses demonstrated that the Pd atoms in the NP-Pd(Ⅱ) were present as Pd(Ⅱ) and were coordinated with both the Cl atoms and the C=C bonds of the polyacetylene.Both the homogeneous distribution of the Pd(Ⅱ) along the polyacetylene backbone and the aggregation of the NP-Pd(Ⅱ) in solution work in conjunction to make this material an ideal catalyst, combining the advantages of both homogeneous and heterogeneous catalysts.supportedbyMinistryofScienceandTechnologyofChina(2011CB932403;2015CB932303); theNationalNaturalScienceFoundationofChina(221420102001;21131005;21390390;21333008)~

Surface Reconstruction and Reactivity of Platinum Iron Oxide Nanoparticles

通讯作者地址: Zhang, PThe electrochemical stability of platinumiron oxide nanoparticles has been studied using X-ray absorption spectroscopy. Samples were monitored for changes in their surface structure and elemental composition after electrochemical cycling in acidic media, which were then correlated with their electronic properties and a thorough analysis of their electrocatalytic activities. In addition to the observation of significant surface restructuring, greater Fe content following electrochemical treatment was found to be associated with higher half-wave potentials and specific current densities (up to 0.965 +/- 0.001 V-RHE and 1.32 +/- 0.03 X 10(-5) mA cm(-2), respectively). This work highlights the potential to improve the electrocatalytic activity of platinumiron oxide nanoparticles by controlling the Fe content and platinumiron bonding, and demonstrates the critical importance of characterizing these nanocatalysts both before and after use.NSERC Canada NSERC University of Washington Canadian Light Source Advanced Photon Source U.S. DOE DE-AC02-06CH11357 State Key Laboratory of Physical Chemistry of Solid Surfaces (Xiamen University) 201401 iChEM (Xiamen University

Shape-Controlled Synthesis of Surface-Clean Ultrathin Palladium Nanosheets by Simply Mixing a Dinuclear Pd-I Carbonyl Chloride Complex with H2O

通讯作者地址: Zheng, NF (通讯作者) Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Collaborat Innovat Ctr Chem Energy Mat, Xiamen 361005, Peoples R China.MOST of China 2011CB932403 ,2009CB930703 ,NSFC 21131005 ,21021061 ,20925103 ,2092300

A graphene-platinum nanoparticles-ionic liquid composite catalyst for methanol-tolerant oxygen reduction reaction

通讯作者地址: Tan, YM (通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Hunan Normal Univ, Coll Chem & Chem Engn, Minist Educ China, Key Lab Chem Biol & Tradit Chinese Med Res, Changsha 410081, Hunan, Peoples R China 电子邮件地址: [email protected] report here that graphene-supported Pt nanoparticles impregnated with the ionic liquid [MTBD][bmsi] which is more oxygen-philic and less methanol-philic than the exterior aqueous solution can exhibit both enhanced electrocatalytic activity and excellent methanol tolerance for oxygen reduction reaction.MOST of China 2011CB932403 2009CB930703 NSF of China 21131005 21021061 20925103 Fok Ying Tung Education Foundation 121011 NSF of Fujian 2009J06005 China Postdoctoral Science Foundation 2010048071

Solvent effect on the synthesis of monodisperse amine-capped Au nanoparticles

通讯作者地址: Zheng, NF (通讯作者) Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China.A remarkable solvent effect in a single-phase synthesis of monodisperse amine-capped Au nanoparticles is demonstrated. Oleylamine-capped Au nanoparticles were prepared via the reduction of HAuCl4 by an amine-borane complex in the presence of oleylamine in an organic solvent. When linear or planar hydrocarbon (e.g., n-hexane, n-octane, 1-octadecylene, benzene, and toluene) was used as the solvent, high-quality monodisperse Au nanoparticles with tunable sizes were obtained. However, Au nanoparticles with poor size dispersity were obtained when tetralin, chloroform or cyclohexane was used as the solvent. The revealed solvent effect allows the controlled synthesis of monodisperse Au nanoparticles with tunable size of 3-10 nm. (C) 2013 Nan-Feng Zheng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.MOST of China 2011CB932403,2009CB930703, NSFC 21131005,21021061 ,20925103 ,20923004 , Fok Ying Tung Education Foundation 12101

Interfacial Effects in Iron-Nickel Hydroxide–Platinum Nanoparticles Enhance Catalytic Oxidation

该研究工作是在郑南峰教授的领导下，由校内外、国内外多个课题组共同努力，历时三年完成。郑南峰、傅钢、陈明树等三个课题组紧密协作负责催化剂的合成、表征、性能测试以及催化机理研究；中国科学院物理研究所谷林研究员主要负责纳米颗粒的亚埃级球差校正高分辨透射电子显微研究；加拿大达尔豪斯大学化学系的张鹏教授课题组和台湾同步辐射研究中心李志甫研究员等参与催化剂的同步辐射X-射线吸收光谱研究。 该工作受到了国家自然科学基金委、科技部、厦门大学、固体表面物理化学国家重点实验室、能源材料化学协同创新中心以及醇醚酯化工清洁生产国家工程实验室的资助与支持。Hybrid metal nanoparticles can allow separate reaction steps to occur in close proximity at different metal sites and accelerate catalysis. We synthesized iron-nickel hydroxide–platinum (transition metal-OH-Pt) nanoparticles with diameters below 5 nanometers and showed that they are highly efficient for carbon monoxide (CO) oxidation catalysis at room temperature. We characterized the composition and structure of the transition metal–OH-Pt interface and showed that Ni2+ plays a key role in stabilizing the interface against dehydration. Density functional theory and isotope-labeling experiments revealed that the OH groups at the Fe3+-OH-Pt interfaces readily react with CO adsorbed nearby to directly yield carbon dioxide (CO2) and simultaneously produce coordinatively unsaturated Fe sites for O2 activation. The oxide-supported PtFeNi nanocatalyst rapidly and fully removed CO from humid air without decay in activity for 1 month

Electrostatic Self-Assembling Formation of Pd Superlattice Nanowires from Surfactant-Free Ultrathin Pd Nanosheets

A facile method has been developed for face-to-face assembly of two-dimensional surfactant-free Pd nanosheets into one-dimensional Pd superlattice nanowires. The length of the Pd nanowires can be well controlled by introducing cations of different concentration and charge density. Our studies reveal that cations with higher charge density have stronger charge-screening ability, and their introduction leads to more positive zeta-potential and decreased electrostatic repulsion between negatively charged Pd nanosheets. Moreover, their surfactant-free feature is of great importance in assembling the Pd nanosheets into superlattice nanowires. While the cations are important for the assembly of Pd nanosheets, the use of poly(vinylpyrrolidone) is necessary to enhance the stability of the assembled superlattice nanowires. The as-assembled segmented Pd nanowires display tunable surface plasmon resonance features and excellent hydrogen-sensing properties.MOST of China 2011CB932403 2014CB932004 NSFC 21131005 21333008 21420102001 NFFTBS J131002

Freestanding palladium nanosheets with plasmonic and catalytic properties

通讯作者地址: Huang, XQ (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Xiamen Univ, Dept Phys, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] metal films can exhibit quantum size and surface effects that give rise to unique physical and chemical properties(1-7). Metal films containing just a few layers of atoms can be fabricated on substrates using deposition techniques(7), but the production of freestanding ultrathin structures remains a significant challenge. Here we report the facile synthesis of freestanding hexagonal palladium nanosheets that are less than 10 atomic layers thick, using carbon monoxide as a surface confining agent. The as-prepared nanosheets are blue in colour and exhibit a well-defined but tunable surface plasmon resonance peak in the near-infrared region. The combination of photothermal stability and biocompatibility makes palladium nanosheets promising candidates for photothermal therapy. The nanosheets also exhibit electrocatalytic activity for the oxidation of formic acid that is 2.5 times greater than that of commercial palladium black catalyst.NSF of China 20925103 20871100 20721001 20703032 MOST of China 2009CB930703 2011CB932403 Fok Ying Tung Education Foundation 121011 NSF of Fujian 2009J06005 Key Scientific Project of Fujian Province 2009HZ0002-