镍基金属有机框架衍生的双功能电催化剂用于析氢和析氧反应（英文）

开发高活性、低成本的析氢反应和析氧反应电催化剂对于能源的可持续发展至关重要。金属有机框架衍生的纳米材料已经成为一类非常有前景的非贵金属双功能电催化剂,但是目前对镍基金属有机框架衍生的双功能电催化剂的深入研究并不全面,其催化活性和稳定性还有待进一步提高。本文制备了一种棒状多孔碳负载镍纳米颗粒的新型电催化剂,并将其用作电催化析氢和析氧反应。实验研究结果表明该类电催化剂表现出优异的析氢和析氧反应活性和长期稳定性,在10 mA·cm~(-2)的电流密度下,析氢反应和析氧反应的过电位分别为120和350 mV。我们认为:材料可控的纳米结构和均匀分布的活性位点共同提升了复合材料的电催化性能。     

多酸在电催化析氢反应中的应用研究进展

电催化水裂解是一种可持续用于生产可再生氢能源的技术。然而,开发高效稳定、低成本的析氢电催化剂仍是一项具有挑战性的任务。多金属氧酸盐(多酸)是一种离散的金属氧簇合物,通常由氧配体和高价的钒(V)、钼(VI)、钨(VI)金属构成。由于多酸含有丰富的氧化还原活性金属中心,因此,近几年来,多酸在水裂解应用研究方面备受关注。本综述将聚焦于多酸在电催化水裂解析氢的应用研究进展。本文还突出强调了电催化析氢目前面临的主要问题,以及对多酸基催化剂及作为催化剂前体在电催化析氢方面的应用及发展前景做了展望。     

纳米二氧化钛光催化剂的制备、活性评价及活性与缺陷关系的综合实验设计

旨在建立一个包括纳米二氧化钛粉体及薄膜的制备、缺陷和活性评价的系统性的应用化学综合实验,并且将电化学工作站用于光电化学活性评价。通过本实验学生不但可以学习半导体纳米粉体及薄膜材料的一般制备方法,而且可以初步掌握利用光/电化学测试技术对材料光催化活性进行评价的基本手段。本实验贯穿了以化学应用能力培养为宗旨的"化学合成→结构与性能关系研究→应用"的全过程。同时,本实验可以引导学生关注太阳能的转化和利用,以及光催化氧化技术用于环境治理的研究和应用。     

多壳层中空镍钴双金属磷化物纳米球用于高效电催化析氧北大核心CSCD

析氧反应是金属-空气电池和电解水制氢等电化学系统中关键的反应,研究其高效稳定非贵金属电催化剂至关重要。本文以金属有机骨架化合物(MOF)作为前驱体,通过高温煅烧制备了具有多壳层中空结构的镍钴双金属磷化物(NiCo-P)。这种独特的结构有利于电解液的渗透,能够提供丰富的暴露活性位点和快速传质路径,同时,镍钴双金属具有协同作用促进电化学性能。结果表明,n(Ni)∶n(Co)=1∶10制备的NiCo-P-0.1催化剂在1.0 mol/L KOH电解液中表现出良好的催化活性和稳定性,在10 mA/cm^(2)电流密度的过电势为329 mV,具有良好的应用前景。本工作为高活性和高稳定性的电催化析氧催化剂的制备提供了一种全新途径。     

电化学二电子氧还原制备过氧化氢研究进展

利用电化学二电子氧还原(2e^-Oxygen Reduction Reaction,2e^-ORR)方法实现过氧化氢(H2O2)的分散式制备,被认为是具有广阔发展前景的技术之一。为实现高的氧还原活性和理想的H₂O₂选择性,设计高性能2e^-ORR电催化剂是该技术的核心关键。尽管现阶段发展的2e^-ORR催化剂已经取得了显著进展,但距离规模化应用仍存在很大的差距。基于此,本文综述了电化学二电子氧还原制备H₂O₂的最新研究进展,首先简要介绍了反应机理和评价方法,并根据机理分析了影响电催化性能的关键因素。随后围绕贵金属催化剂、碳基催化剂、单原子及分子催化剂的最新研究进展,阐述了提升催化剂活性与H₂O₂选择性的主要策略。最后,针对电化学二电子氧还原制备H₂O₂体系面临的关键问题和挑战,对该领域未来的发展趋势进行了展望。     

用于电化学水氧化的铁、镍、钴金属及其二元金属纳米颗粒比较研究（英文）

从环境兼容角度来设计应用于氧析出反应的电催化剂是否有效、耐用和廉价对能源转化过程至关重要.本文报告了一种快速制备低成本、原料丰富的金属催化剂制备方法.通过一步电化学沉积法在钛金属基材上制备了铁、镍、钴金属及其钴镍、钴铁二元金属纳米颗粒.采用场发射电子显微镜(FE-SEM)、能量散射X-射线能谱(EDX)、X-射线衍射光谱(XRD)、X-射线光电子能谱(XPS)和电化学技术对制备的不同纳米颗粒进行了表征.电化学结果显示,在合成的五种钛基金属纳米催化剂中,钛基上沉积钴金属纳米颗粒(Ti/Co)电极在0.l mol·L~(-1)氢氧化钾溶液中氧析出反应的电催化活性最好,0.70 V(相对于银/氯化银电极)的电流密度为10.0 mA·cm~(-2).经优化后Ti/Co电极的过电位(η)很小,当电流密度为10.0 mA·cm~(-2)时η为0.43 V,质量活性高达105.7 A·g~(-1),逆转频率(TOF)值为1.63×10~(-3) s~(-1),这些与当前最好的碳载铂(Pt/C)和氧化钌(RuO_2)电催化剂的性能相当.此外,通过计时电位技术对优化后Ti/Co电极的耐久性进行了测试,发现该电极在碱性溶液中氧析出反应的稳定性良好.本工作制备的钛金属基材上电化学沉积金属钴纳米颗粒具有高催化活性、高稳定性、原料来源丰富、廉价且易于大规模生产,在工业化水分解领域具有潜在的应用前景.     

基于理论指导的电催化剂调控:从机制分析到结构设计（英文）

电催化在许多清洁能源转换技术中起着核心作用,能够与光伏、风电和水电等可再生能源发电系统耦合,解决全球能源和气候危机.一些重要的电化学转化过程,包含析氢反应(HER)、析氧反应(OER)、氧还原反应(ORR)、氮还原反应(NRR)和二氧化碳还原(CO2RR)等,引起了广泛的研究兴趣.实现这些电催化技术大规模应用的核心在于开发先进的电催化材料.传统电催化剂的研发依赖于“试错法”实验合成,这一过程耗时漫长、成本较高.近20年来,基于理论指导的新材料开发成为更先进的电催化剂设计思路,这主要受益于:(1)重要的基本理论、活性描述符与催化剂机制的确立;(2)计算化学在电化学领域的成熟.这些进展揭示了电催化剂的构效规律,加速了电催化剂的研发过程.本文梳理了电催化剂设计理论发展的关键历程.首先,萨巴捷原则指出理想催化剂的吸附应该是“中庸”的:过弱的吸附无法使反应发生,过强的吸附将导致催化剂表面被覆盖而无法进一步反应.火山型曲线准确描绘了这一现象,并为此提供了可定量的数学表达,但仍缺少量化吸附的物理量.随着计算机技术与密度泛函理论的不断发展,人们能够获得吸附能、活化能等微观物理量.同时, Br?nste...     

泡沫镍上电沉积花瓣状NiFeO_xH_y/rGO用于析氧反应（英文）

开发碱性体系的高效低成本析氧电催化剂是由可再生能源转化制氢的关键。本研究通过在泡沫Ni基底上原位电化学沉积的方法制备了花瓣状NiFeO_xH_y和NiFeO_xH_y/rGO复合催化剂用于析氧反应。花瓣状的结构不仅明显提高了催化剂的比表面积,而且暴露了更多的层状边缘和缺陷,进而增加了催化剂的活性中心。还原氧化石墨烯的加入进一步提升了催化剂的电导和析氧电催化性能,通过优化NiFeO_xH_y/r GO在1 mol/L KOH溶液中的析氧性能为:过电位200 mV(10 mA/cm~2)、Tafel斜率29.11 mV/decade,并且保持了较好的稳定性。     

咪唑四氟硼酸盐离子液体中磷钼酸掺杂聚吡咯薄膜修饰电极的制备及其电催化活性

以1-丁基-3-甲基咪唑四氟硼酸盐(BMIMBF4)离子液体作为介质,利用电化学方法在铂电极表面制备了磷钼酸掺杂聚吡咯薄膜;采用扫描电子显微镜观察了所制备的薄膜的形貌,利用热重分析评价了其热稳定性,利用循环伏安法测定了其电化学活性和对甲醇的电催化氧化活性.结果表明,与传统的硫酸溶液相比,以BMI-MBF4离子液体作为反应介质制备的修饰电极的表面形貌更均匀,电化学活性和对甲醇的电催化氧化活性更强.     

Ni(OH)_2/Ni/g-C_3N_4复合材料:一种高效的析氢电催化剂（英文）

高效析氢催化剂的制备仍是目前亟待解决的重要课题。本研究采用液相浸渍原位还原法制备了Ni(OH)_2/Ni/gC_3N_4复合催化剂,并与碳纸(CP)组合作为微生物电解电池(MEC)的阴极。采用SEM、TEM、XRD、XPS和电化学分析等技术对所制备的催化剂样品的结构性质和析氢电催化性能进行了分析研究。结果表明,Ni(OH)_2/Ni/g-C_3N_4催化剂在100 A/cm~2的电流密度驱动下具有优秀的析氢过电位(1881 mV)、较低的电荷转移电阻(10.86Ω)和较低的塔费尔斜率(44.3 mV/dec),其电化学活性优于纯g-C_3N_4催化剂和CP,甚至可与Pt催化剂媲美。     

Oxygen Evolution Reaction on Nanoporous Gold Modified with Ir and Pt: Synergistic Electrocatalysis between Structure and Composition

Active oxygen evolution reaction electrocatalysts for water splitting have received great attention because of their importance in the utilization of renewable energy sources. Here, the electrochemical oxygen evolution reaction activities of a nanoporous gold (NPG)‐based electrode in acidic media are investigated. The dependence of the oxygen evolution reaction activity on the NPG surface area shows that the large electrochemical surface areas of the NPG are effectively utilized to enhance electrocatalytic activity. The NPG surfaces are modified with Pt using atomic layer electrodeposition methods, and the resulting NPG@Pt exhibited enhanced electrocatalytic activities compared to those of the NPG and flat Pt electrodes. Ir‐modified NPG (NPG@Ir) electrodes are prepared by spontaneous exchange of Ir on NPG surfaces and exhibit enhanced electrocatalytic activity compared to that of flat Ir surfaces. The modification of NPG@Pt with Ir results in NPG@Pt/Ir electrodes, and their electrocatalytic activities exceed those of NPG@Ir. The enhanced oxygen evolution reaction activity on NPG@Pt/Ir over that on NPG@Ir surfaces is examined by X‐ray photoelectron spectroscopy. The oxygen evolution reaction activity on NPG@Pt/Ir surfaces demonstrates synergistic electrocatalysis between the nanoporous surface structure and active electrocatalytic components.     

Electrochemical properties of Ebonex®/Pt anodes

The electrochemical behavior of platinized Ebonex® was studied. The electrochemical and semiconductor properties of electrodes can be varied within wide limits by thermal treatment of Ebonex®/Pt, which selectively affects the electrocatalytic activity of anodes in the oxygen evolution reaction. The reduction peak of platinum oxides on the cyclic voltammetry (CV) curves can be used as a correlation parameter when evaluating the electrocatalytic activity of Ebonex®/Pt electrodes in the oxygen evolution reaction.     

Advances in efficient electrocatalysts based on layered double hydroxides and their derivatives

The explore and development of electrocatalysts have gained significant attention due to their indispensable status in energy storage and conversion systems, such as fuel cells, metal–air batteries and solar water splitting cells. Layered double hydroxides(LDHs) and their derivatives(e.g., transition metal alloys, oxides, sulfides, nitrides and phosphides) have been adopted as catalysts for various electrochemical reactions, such as oxygen reduction, oxygen evolution, hydrogen evolution, and CO_2 reduction, which show excellent activity and remarkable durability in electrocatalytic process. In this review, the synthesis strategies, structural characters and electrochemical performances for the LDHs and their derivatives are described. In addition, we also discussed the effect of electronic and geometry structures to their electrocatalytic activity. The further development of high-performance electrocatalysts based on LDHs and their derivatives is covered by both a short summary and future outlook from the viewpoint of the material design and practical application.     

Titanium coated with high-performance nanocrystalline ruthenium oxide synthesized by the microwave-assisted sol–gel procedure

Ruthenium oxide coating on titanium was prepared by the sol–gel procedure from well-defined colloidal oxide dispersions synthesized by the microwave (MW)-assisted hydrothermal route under defined temperature and pressure heating conditions. The dispersions were characterized by dynamic light scattering (DLS) measurements and scanning electron microscopy (SEM). The electrochemical properties were analyzed as capacitive performances gained by cyclic voltammetry and electrochemical impedance spectroscopy and as the electrocatalytic activity for oxygen evolution from acid solution. The obtained dispersions were polydisperse and contained regular particles and agglomerates of increasing surface energy and decreasing particle size as the MW-assisted heating conditions were intensified. Owing to these features of the precursor dispersions, the obtained coatings had considerably improved capacitive performances and good electrocatalytic activity for oxygen evolution at high overpotentials.     

Scanning Electrochemical Microscopy of Individual Catalytic Nanoparticles

Electrochemistry at individual metal nanoparticles (NPs) can provide new insights into their electrocatalytic behavior. Herein, the electrochemical activity of single AuNPs attached to the catalytically inert carbon surface is mapped by using extremely small (≥3 nm radius) polished nanoelectrodes as tips in the scanning electrochemical microscope (SECM). The use of such small probes resulted in the spatial resolution significantly higher than in previously reported electrochemical images. The currents produced by either rapid electron transfer or the electrocatalytic hydrogen evolution reaction at a single 10 or 20 nm NP were measured and quantitatively analyzed. The developed methodology should be useful for studying the effects of nanoparticle size, geometry, and surface attachment on electrocatalytic activity in real‐world application environment.     

Mechanism of oxygen reactions at porous oxide electrodes. Part 2--Oxygen evolution at RuO2, IrO2 and Ir(x)Ru(1-x)O2 electrodes in aqueous acid and alkaline solution

The kinetics and mechanism of the oxygen evolution reaction at a series of RuO(2)/IrO(2) mixed oxides in aqueous acid and alkaline solution has been examined using a variety of electrochemical methods. Factors affecting the electrocatalytic activity have been elucidated and novel oxygen evolution mechanisms in terms of reactive oxyruthenium and oxyiridium surface groups are proposed.     

硫酸介质中Ti／SnO2／PbO2析氧阳极的研究

由于硫酸溶液具有高的电导、一般条件下性质稳定、价格相对低廉等优点，所以电化学合成大多在硫酸溶液中进行．阳极析氧是电化学合成不可避免的阳极过程．但因硫酸的强腐蚀性，以及从阳极析出的氧的强氧化性，使得能满足工业生产的阳极材料很缺乏．自１９５０年荷兰Ｈｅｎ...     

Comparison of electrocatalytic characterization of Ti/Sb-SnO<Subscript>2</Subscript> and Ti/F-PbO<Subscript>2</Subscript> electrodes

Electrocatalytic oxidation is a promising process for degrading toxic and biorefractory organic pollutants in wastewater treatment. Selection of electrode materials is crucial for electrochemical oxidation process. In this study, Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes were chosen to compare their electrocatalytic characterization, which were prepared by electrodeposition and thermal decomposition method, respectively. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The linear polarization curves show that Ti/Sb-SnO₂ electrodes possess higher oxygen evolution overpotential than Ti/F-PbO₂ electrodes. But the stability and corrosion resistance ability of Ti/F-PbO₂ electrode was higher than that of Ti/Sb-SnO₂ electrode. The electrocatalytic activity of Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes was examined for the electrochemical oxidation of malachite green (MG). The bulk electrolysis shows that the Ti/Sb-SnO₂ electrodes exhibit the higher electrocatalytic activity for the degradation of MG than Ti/F-PbO₂ electrodes, and the degradation process is good fitting for the pseudo-first order reaction. The higher electrocatalytic activity of Ti/Sb-SnO₂ electrodes can be attributed to the higher oxygen evolution overpotential.     

Size-dependent electrocatalytic activity of gold nanoparticles on HOPG and highly boron-doped diamond surfaces

Gold nanoparticles were prepared by electrochemical deposition on highly oriented pyrolytic graphite (HOPG) and boron-doped, epitaxial 100-oriented diamond layers. Using a potentiostatic double pulse technique, the average particle size was varied in the range from 5 nm to 30 nm in the case of HOPG as a support and between < 1 nm and 15 nm on diamond surfaces, while keeping the particle density constant. The distribution of particle sizes was very narrow, with standard deviations of around 20% on HOPG and around 30% on diamond. The electrocatalytic activity towards hydrogen evolution and oxygen reduction of these carbon supported gold nanoparticles in dependence of the particle sizes was investigated using cyclic voltammetry. For oxygen reduction the current density normalized to the gold surface (specific current density) increased for decreasing particle size. In contrast, the specific current density of hydrogen evolution showed no dependence on particle size. For both reactions, no effect of the different carbon supports on electrocatalytic activity was observed.     

表面Co2CrO4电化学转化为CoOOH/CrOOH及其增强电催化析氧中的性能

以清洁能源发电为动力的水分解技术是一种很有应用前景的制氢方法,可以缓解日益增长的能源消耗和公众高度关注的环境问题.水分解的氧化过程,即析氧反应(OER),是一个四电子-质子耦合反应,其动力学缓慢,是实现高效电解水的技术难题.以RuO2和IrO2为代表的贵金属氧化物表现出极高的催化活性,但受限于储量低及价格昂贵,很难广泛...