表界面调控电催化析氧反应

开发高效绿色清洁能源已引起研究者们的广泛关注。电解水是一种大规模且可持续生产高纯氢能源技术。然而,阳极析氧反应电催化剂的高过电位和不稳定性制约了电解水技术的大规模应用,合理设计电催化剂的结构可显著优化其反应热力学和动力学,提高电解水技术的能量转换效率。表界面是电催化反应发生的主要场所,通过调控电催化剂表面的本征结构或构筑异质界面等系列表界面化学工程对电催化剂进行改性,可以有效改善材料的催化活性和稳定性。本文概述了当前表界面调控策略在电催化析氧反应中的研究进展,重点介绍了表界面调控层状双金属氢氧化物、钙钛矿型氧化物、尖晶石型化合物及合金材料的研究现状,阐述了高效稳定析氧反应电催化剂的设计思路。讨论了表界面调控策对催化剂表界面微结构和电子态的影响以及设计新型析氧反应电催化剂中面临的问题。最后,展望了表界面调控应用于析氧反应电催化剂的前景。     

电催化剂设计中表面和界面工程的最新进展

电催化已发展为一种涉及电化学、表面科学、材料科学和催化科学等众多科学分支的交叉学科和综合技术,在工农业生产、经济和国防建设、能源开发和环境保护等方面发挥了不可或缺的作用。金属纳米催化剂的可控合成和创新构建,极大地推动了电催化的广泛应用和巨大进展。过渡金属尤其是贵金属Pt、Pd等电催化剂,在电催化中表现出良好的选择性、活性和稳定性,很难完全被其他材料所取代。制约电催化可持续发展的瓶颈问题是,如何设计、合成和构建高性能低成本的金属纳米催化剂。为实现这一目标,人们付出了大量的努力并取得了一些可喜的进展。电催化是发生在电解质与电极材料表面和界面的异相催化反应,金属纳米电催化剂的性能与其形貌、结构、尺寸和组成相关。本文着力总结和探讨如何从表面工程和界面工程角度设计、合成和构筑金属纳米结构及其复合结构,以实现金属电催化剂性能和成本的双优化。本文提出了在金属纳米结构及其复合结构的设计、合成和构筑过程中需要考虑的几个重要的表面和界面因素,即表面面积、表面晶面、活性位点和界面结构等。首先,有效表面面积越大,越有利于电催化反应。我们总结了增大催化剂有效活性面积的四种有效方法,包括减小颗粒尺寸、制成薄层二维纳米结构、增大粗糙度、形成中空、多孔或介孔及框架结构等。其次,表面晶面也可决定电催化的性能。我们简单总结了低指数晶面和高指数晶面在表面能、晶面形成和催化活性上的“挑战与机遇”矛盾关系,并简要阐述了晶面选择性即晶面效应以及晶面与尺寸的依赖关系。再次,活性位点一般指的是低配位表面原子位点,是电催化反应的决定因素之一。我们描述了活性位点与表面和界面结构特征、纳米晶表面晶面、表面缺陷和空穴、表面面积和粒子尺寸等的依赖关系。最后,界面结构工程是调控电催化性能的最丰稔因素。我们简述了界面结构的形成、分类及其对优化界面活性位点的成分和几何结构、表面悬键和原子配位数、电子结构与电子传递、质子传输和物种交换等方面调控作用,并在界面工程的基础上推介了贵金属基复合结构的合成、组装的几种典型方式。本文以具体示例的形式,分别从表面工程和界面工程的角度,扼要介绍了本课题组最近在甲酸氧化、氧还原、析氢等电催化反应体系中贵金属基纳米结构及其复合纳米结构电催化剂的设计、合成与构筑的具体做法。我们分别介绍了低指数晶面和高指数晶面的表面设计对于提高催化剂性能的关键作用。对于低指数晶面,我们重点介绍了如何获得相似尺寸的不同表面晶面以研究其晶面效应,如何维持相同晶面调节尺寸以研究其尺寸效应,如何建造与电极有良好电学接触的低指数晶面纳米结构,以利于提升其电催化性能。对于高指数晶面,介绍了几种形成高指数晶面的途径,并阐明了其晶面对电催化性能的影响。另一方面,我们从金属纳米结构及其复合结构的成分和结构调控策略介绍了界面构建对于提升电催化性能的奇妙作用,包括建造多金属纳米结构、与二维材料负载组装和利用界面极化。由此,本文总结了表面和界面工程对于电催化剂设计、合成和构筑目前面临的三个关键挑战。     

电催化剂设计中表面和界面工程的最新进展（英文）

电催化已发展为一种涉及电化学、表面科学、材料科学和催化科学等众多科学分支的交叉学科和综合技术,在工农业生产、经济和国防建设、能源开发和环境保护等方面发挥了不可或缺的作用.金属纳米催化剂的可控合成和创新构建,极大地推动了电催化的广泛应用和巨大进展.过渡金属尤其是贵金属Pt、Pd等电催化剂,在电催化中表现出良好的选择性、活性和稳定性,很难完全被其他材料所取代.制约电催化可持续发展的瓶颈问题是,如何设计、合成和构建高性能低成本的金属纳米催化剂.为实现这一目标,人们付出了大量的努力并取得了一些可喜的进展.电催化是发生在电解质与电极材料表面和界面的异相催化反应,金属纳米电催化剂的性能与其形貌、结构、尺寸和组成相关.本文着力总结和探讨如何从表面工程和界面工程角度设计、合成和构筑金属纳米结构及其复合结构,以实现金属电催化剂性能和成本的双优化.本文提出了在金属纳米结构及其复合结构的设计、合成和构筑过程中需要考虑的几个重要的表面和界面因素,即表面面积、表面晶面、活性位点和界面结构等.首先,有效表面面积越大,越有利于电催化反应.我们总结了增大催化剂有效活性面积的四种有效方法,包括减小颗粒尺寸、制成薄层二维纳米结构、增大粗糙度、形成中空、多孔或介孔及框架结构等.其次,表面晶面也可决定电催化的性能.我们简单总结了低指数晶面和高指数晶面在表面能、晶面形成和催化活性上的"挑战与机遇"矛盾关系,并简要阐述了晶面选择性即晶面效应以及晶面与尺寸的依赖关系.再次,活性位点一般指的是低配位表面原子位点,是电催化反应的决定因素之一.我们描述了活性位点与表面和界面结构特征、纳米晶表面晶面、表面缺陷和空穴、表面面积和粒子尺寸等的依赖关系.最后,界面结构工程是调控电催化性能的最丰稔因素.我们简述了界面结构的形成、分类及其对优化界面活性位点的成分和几何结构、表面悬键和原子配位数、电子结构与电子传递、质子传输和物种交换等方面调控作用,并在界面工程的基础上推介了贵金属基复合结构的合成、组装的几种典型方式.本文以具体示例的形式,分别从表面工程和界面工程的角度,扼要介绍了本课题组最近在甲酸氧化、氧还原、析氢等电催化反应体系中贵金属基纳米结构及其复合纳米结构电催化剂的设计、合成与构筑的具体做法.我们分别介绍了低指数晶面和高指数晶面的表面设计对于提高催化剂性能的关键作用.对于低指数晶面,我们重点介绍了如何获得相似尺寸的不同表面晶面以研究其晶面效应,如何维持相同晶面调节尺寸以研究其尺寸效应,如何建造与电极有良好电学接触的低指数晶面纳米结构,以利于提升其电催化性能.对于高指数晶面,介绍了几种形成高指数晶面的途径,并阐明了其晶面对电催化性能的影响.另一方面,我们从金属纳米结构及其复合结构的成分和结构调控策略介绍了界面构建对于提升电催化性能的奇妙作用,包括建造多金属纳米结构、与二维材料负载组装和利用界面极化.由此,本文总结了表面和界面工程对于电催化剂设计、合成和构筑目前面临的三个关键挑战.     

化学功能化增强贵金属纳米晶电催化性能（英文）

基于电催化过程的可再生和清洁能源的生产、转换和储存技术(如水电解和燃料电池)是缓解全球能源短缺和环境污染问题的有效手段.目前,水电解和燃料电池技术的实际应用缺乏高效、稳定的电催化剂来驱动动力学迟缓的阴极和阳极反应.贵金属纳米晶由于其独特的电子结构和高化学惰性而具有高电催化活性和稳定性.为了提升贵金属纳米晶的本征电催化性能,大量研究聚焦在利用面积效应、晶面效应和不同组分之间的协同效应来调控贵金属的粒径、形貌和化学成分.事实上,贵金属纳米晶的电催化性能也与其表/界面性质密切相关.电催化剂表面的化学功能化可以改变电极/电解质界面结构,从而提高电催化活性和选择性,这对开发新型高效的电催化剂具有重要的理论意义.本文系统介绍了本课题组开发的聚胺(PAM)功能化贵金属纳米电催化剂的合成方法及其在燃料电池和电解池等能源转换装置中的应用,具体包括:通过引入PAM控制反应动力学来调控纳米晶体的结构和形态,构建界面功能化贵金属纳米电催化剂;利用金属表面修饰的PAM分子改变表面催化位点的电子结构、配位环境等物理化学性质来控制反应物和中间体等的吸附行为,从而达到调节催化活性的目的;采用PAM分子来隔离特定活性位...     

团簇Au/CeO2的制备及其催化CO氧化反应构效关系的研究

负载型Au催化剂因其在诸多反应过程中的高催化活性而备受研究者关注.然而针对负载型催化剂中Au物种结构的有效调控,以及催化过程中真实构-效关系的探索一直充满了挑战.用CeO₂为Au物种担载基底,通过简单煅烧处理引起的CeO₂结构变化,进而实现Au/CeO₂之间界面作用力的调控.此研究发现Au纳米颗粒中Au⁰物种具备更为高效的催化室温CO氧化活性,结合多种原位表征分析,其室温条件下催化转化效率更依赖于CO吸附能力.而相比于单原子Au₁和纳米Au颗粒,所制备的团簇Au/CeO₂催化剂在较高温度(>50℃)展现出优异的催化CO氧化反应性能.随着温度升高,催化剂表界面O参与的MvK反应路径更易发生,因此具有更多表界面活性O物种和Au^δ+位点的团簇Au/CeO₂催化剂展现出最为优异的催化CO氧化性能.这些发现为高效负载型Au催化剂的制备提供了新思路并深化了对Au/CeO₂催化作用机制的理解.     

通过熔体自由基反应调控聚丙烯体系的链结构和相结构

熔融反应加工是聚合物改性和制备聚合物纳米复合材料的重要途径之一.在此过程中,多数加成聚合物由于受到热、剪切或引发剂作用,通常可原位形成大分子自由基反应中间体.我们系统地研究了如何利用这类大分子自由基调控聚合物分子链的拓扑结构和聚合物纳米复合体系的相结构与界面.然而,某些聚合物大分子自由基,如聚丙烯(PP),受其分子链化学结构决定,在熔融反应条件下非常易于发生降解.研究发现,将可控自由基聚合中调控自由基反应活性的方法应用在熔融反应过程中可以显著抑制PP的降解,促进主反应的发生,在制备长链支化聚合物、调控聚合物纳米复合材料的相结构方面发挥了重要作用.本文介绍了本研究组近几年来通过熔体自由基反应调控PP体系的链结构和相结构的相关研究工作,如实现PP的长链支化,制备高熔体强度PP;在制备PP/C60 、PP/碳纳米管(CNTs)纳米复合材料过程中,利用熔体界面区域所发生的自由基反应,提高了纳米粒子与PP的界面相互作用,改善了纳米粒子在PP中的分散状态等.     

双金属纳米材料与催化

双金属纳米材料作为工业上少见的一类催化剂材料,在合成过程中可通过对其组成、结构晶粒大小尺寸的调控,实现其催化性能的合理调控,因此,近年来备受催化材料化学领域科技工作者的广泛关注.随着纳米材料调控合成方面的技术进步,具有均一小尺寸可控结构的纳米材料对于制备高效催化剂材料和研究催化反应机理具有重要的意义.结合纳米技术探索开发设计新型的双金属纳米催化剂材料颇具挑战性.本文围绕双金属纳米催化剂的合成、结构及其相关催化性能,从不同的双金属纳米催化剂出发,对催化剂的性能提高、催化机理研究的若干问题和分析手段及方法在催化研究中的进展发表一点初浅认识.     

高分子固液复合界面与液体黏附调控

受猪笼草口缘区润滑效应启发,将低表面能液体注入高分子微纳米多孔结构中可构筑高分子固液复合界面.与超疏水固体界面相比,固液复合界面展现出独特的浸润性和黏附性.界面黏附是高分子复合材料重要的性质之一,实现界面黏附的精准调控对促进这类材料的发展和应用具有至关重要的作用.本文重点从稳定性调控、方向性调控以及原位可逆调控3个方面综述提升固液复合界面黏附可控性的工作,通过在表面微米结构中组装纳米层状及异质纳米层状结构,提高界面黏附的稳定性;使用界面薄层定向冷冻干燥法、激光刻蚀法以及复型法等方法,构筑具有取向结构的高分子固液复合界面,实现界面黏附的方向性调控;通过在界面中引入快速响应的智能基元,设计智能响应高分子固液复合界面,实现界面黏附的原位可逆调控.最后,概述了这类材料目前存在的问题并展望了其未来发展的方向.     

金属纳米复合催化剂合成与应用的最新进展

随着纳米技术的发展,金属纳米复合材料由于其特殊的物理化学性质和潜在的催化应用受到越来越多的关注。本文系统地介绍了金属纳米复合催化剂最新的研究进展。首先,我们介绍了一些金属纳米复合催化剂的合成方法。其次,为了更好的优化催化剂的结构与催化活性的关系,并深入理解催化反应机理,我们讨论了金属纳米复合催化剂一些重要因素（包括粒子粒径、形貌、组成、载体或配体）对催化活性和选择性的影响。最后,我们进一步介绍了金属纳米复合催化剂在还原不饱和化学键中的应用（N=O,N≡C和C=O）,同时还对金属纳米复合催化剂的发展方向进行了展望。     

金属纳米复合催化剂合成与应用的最新进展

随着纳米技术的发展,金属纳米复合材料由于其特殊的物理化学性质和潜在的催化应用受到越来越多的关注。本文系统地介绍了金属纳米复合催化剂最新的研究进展。首先,我们介绍了一些金属纳米复合催化剂的合成方法。其次,为了更好的优化催化剂的结构与催化活性的关系,并深入理解催化反应机理,我们讨论了金属纳米复合催化剂一些重要因素(包括粒子粒径、形貌、组成、载体或配体)对催化活性和选择性的影响。最后,我们进一步介绍了金属纳米复合催化剂在还原不饱和化学键中的应用(N=O,N≡C和C=O),同时还对金属纳米复合催化剂的发展方向进行了展望。     

Ordered arrays of gold nanostructures from interfacially assembled Au@PNIPAM hybrid nanoparticles

In this Article, we report on the assembly of hybrid Au@PNIPAM core-shell particles at the air/water interface, their transfer onto solid substrates, and the controlled combustion of the organic material to produce arrays of gold nanoparticles. A detailed investigation on the assembly behavior of such soft hybrid colloids at the air/water interface was performed by correlating the surface pressure-area isotherms with SEM and AFM images from samples transferred at different surface pressures. The hybrid particles display a complex behavior at the interface, and we could distinguish three distinct phases with varying interparticle spacings at different compression. The transfer process presented enables the decoration of topologically structured substrates with gold nanoparticle arrays, and the order of the initial monolayers is retained in the arrays of inorganic gold nanoparticles. The change in monolayer morphology upon compression can therefore be used to tailor the interparticle distance between approximately 650 and 300 nm without exchanging the colloids. More sophisticated gold nanostructures can be patterned into symmetric arrays using a similar protocol, which we demonstrate for nanostars and nanorods.     

Host-guest supramolecular chemistry at solid-liquid interface: An important strategy for preparing two-dimensional functional nanostructures

Supramolecular self-assembly,an important strategy in nanotechnology,has been widely studied in the past two decades.In this review,we have introduced the recent progress on construction of two-dimensional(2D)nanostructures by host-guest supramolecular chemistry at solid-liquid interface,and the interactions between the host assembly and the guest molecules are the major concerns.At first,the hydrogen bonds connected hybrid structures are discussed.And then we have paid a close attention on the surface-confined condensation reactions that has flourished recently in direct preparing novel nanostructures with increasing structural complexity.In the end,the cavity confinement of the 2D supramolecular host-guest architectures has been studied.On the basis of the above-mentioned interactions,a group of functional hybrid structures have been prepared.Notably,scanning tunneling microscopy(STM),a unique technique to probe the surface morphology and information at the single molecule level,has been used to probe the formed structures on highly oriented pyrolytic graphite(HOPG)surface.     

Synthesis of Au–ZnS hybrid nanostructures and their application for electrochemical biosensor

Au–ZnS core–shell nanostructures were grown onto the transparent indium tin oxide (ITO) thin film-coated glass surface by successive electrodeposition of Au and ZnS in cyclic voltammetry. The resulting hybrid nanostructures were characterized using scanning electron microscopy, X-ray diffraction, UV–vis spectroscopy, and electrochemical impedance spectroscopy. The glucose oxidase (GOD) was immobilized onto the surface of the Au–ZnS hybrid nanostructures in silica sol–gel network. Furthermore, the Au–ZnS nanostructures demonstrate an enhanced direct electron transfer between GOD and the electrode due to their unique chemical and electrocatalytic properties and their synergy effect. The analytical performance of the GOD-based electrode was improved greatly compared with that of ITO substrate modified by Au or ZnS nanostructures alone. The proposed enzyme electrode based on Au–ZnS hybrid nanomaterials displays high sensitivity and wide linear range in the determination of glucose. The Au–ZnS hybrid nanostructures have potential for “green chemistry” application in the fabrication of enzyme-based electrochemical biosensors.     

TiO2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity

MWCNT/TiO₂ hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO₂ nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO₂ was 20%, MWCNT/TiO₂ hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO₂ nanostructures at 400 °C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO₂ and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue.     

Self-assembly of ionic liquids-stabilized Pt nanoparticles into two-dimensional patterned nanostructures at the air-water interface

In this paper, we demonstrate the self-assembly of ionic liquids (ILs)-stabilized Pt nanoparticles into two-dimensional (2D) patterned nanostructures at the air-water interface under ambient conditions. Here, ILs are not used as solvents but as mediators by virtue of their pronounced self-organization ability in synthesis of self-assembled, highly organized hybrid Pt nanostructures. It is also found that the morphologies of the 2D patterned nanostructures are directly connected with the quantities of ILs. Due to the special structures of ILs-stabilized Pt nanoparticles, 2D patterned Pt nanostructures can be formed through the pi-pi stack interactions and hydrogen bonds. The resulting 2D patterned Pt nanostructures exhibit good electrocatalytic activity toward oxygen reduction.     

Recent developments and applications of hybrid surface plasmon resonance interfaces in optical sensing

Nanostructured noble metals exhibit an intense optical near field due to surface plasmon resonance, therefore promising widespread applications and being of interest to a broad spectrum of scientists, ranging from physicists, chemists, and materials scientists to biologists. A wealth of research is available discussing the synthesis, characterization, and application of noble metal nanoparticles in optical sensing. However, with respect to the sensitivity of the frequency and width of these surface plasmon resonance modes to the particle’s shape, size, and environment, in nearly every case, success strongly depends on the availability of highly stable, adhesive, and sensitive nanoparticles. This undoubtedly presents a challenging task to nanofabrication. The past decade has witnessed fascinating advances in this field, in particular, the construction of oxide-based hybrid plasmonic interfaces to overcome the problem addressed above by (1) coating the metallic nanostructures with thin overlayers to form sandwiched structures or (2) embedding metallic nanostructures in a dielectric matrix to obtain metal/dielectric matrix nanocomposite films. In this critical review, we focus on recent work related to this field, beginning with a presentation of hybrid films with enhanced structural and optical stability, readily and selectively designed using chemical and physical techniques. We then illustrate their interesting optical properties and demonstrate exciting evidence for the postulated application in surface plasmon sensing fields. Finally, we survey the work remaining to be done for that potential to be realized.     

Supramolecular nanostructures based on bacterial reaction center proteins and quantum dots

Design of the nanostructures based on membrane proteins (the key functional elements of biomembranes) and colloid nanoparticles is a fascinating field at the interface of biochemistry and colloids, nanotechnology and biomedicine. The review discusses the main achievements in the field of ultrathin films prepared from bacterial reaction center proteins and light-harvesting complexes, as well as these complexes tagged with quantum dots. The principles of preparation of these thin films and their structure and properties at different interfaces are described; as well as their characteristics estimated using a combination of the modern interfacial techniques (absorption and fluorescence spectroscopy, atomic force and Brewster angle microscopy, etc.) are discussed. Further approaches to develop the nanostructures based on the membrane proteins and quantum dots are suggested. These supramolecular nanostructures are promising prototypes of the materials for photovoltaic, optoelectronic and biosensing applications.     

Surface-Enhanced Raman Scattering (SERS) on transition metal and semiconductor nanostructures

Surface-Enhanced Raman Scattering (SERS) spectroscopy has experienced a rapid growth over the past 30 years, and has become a valuable tool in various research areas. In conjunction with recent explosive development of nanoscience and nanotechnology, the SERS-active substrates have also expanded from traditional Group 11 metals (Au, Ag, Cu) to non-Group 11 nanostructures. This paper gives an overview of historical advances in the use of non-Group 11 nanostructures as substrates for SERS. Several possible mechanisms and important factors for SERS from non-Group 11 nanostructures are discussed in detail. The SERS from non-Group 11 nanostructures provides many significant applications in surface, interface analysis and biochemical detection. It is reasonable to believe that the advancement in the non-Group 11 nanostructures-based SERS-active substrates will lead to a more promising future for the SERS technology in surface science, spectroscopy and biomedicine.     

阳极氧化铝模板限域制备一维杂化纳米材料及其多样化应用的研究进展

一维杂化纳米材料以其独特的物理化学性质,在电学、光学、催化等领域得到了广泛的应用。 其制备方法对一维杂化纳米材料性能的改变和调控显得至关重要。 模板法作为一种简单而普适的合成工艺,近几年来被广泛应用于纳米结构和纳米阵列的合成。 本文主要介绍了阳极氧化铝(AAO)模板法制备一维杂化纳米材料整体情况、AAO模板结合其他技术材制备材料的方法、一维杂化纳米材料在刺激响应性器件、能量存储与转换器件、催化等众多领域的应用。