金属基磷化物纳米材料制备与电催化应用研究进展

处于纳米尺度的磷化物及其与贵金属构成的复合材料具有独特的物理和化学性质,在电催化领域有广泛应用。例如,在甲醇电催化氧化反应中,由于磷(P)比金属铂(Pt)或钯(Pd)等具有更大的电负性,金属原子的外层电子被P吸引而偏向P原子,从而间接提高了Pt或Pd对CO类中间产物的耐受性;在电解水析氢反应中,P可以作为质子受体,增强H⁺在金属上的吸附,从而促进析氢反应;在电解水析氧反应中,金属基磷化物容易被氧化成氧化物和氢氧化物,从而形成氧化物/氢氧化物-磷化物界面,进一步促进析氧反应。纳米颗粒的催化性能很大程度上取决于催化剂的结构、组分、组分之间的相互作用以及活性位点的电子结构,因此,对金属基磷化物基纳米复合材料的这些性质进行合理调控是提升其电催化性能的关键。本文所综述的材料范围包含金属基磷化物本身及其与贵金属构成的纳米复合材料,首先概括介绍金属基磷化物基纳米复合材料的合成方法和表征技术,进而阐述如何利用复合材料中晶格应变和电子耦合等物理效应提升电催化活性和稳定性。最后,围绕金属基磷化物基纳米复合材料电催化性能进一步提升的问题,对其未来合成策略和发展进行展望。     

水热法制备镍负载硫磷双掺杂石墨烯电极及其电催化析氢性能研究

设计一种高活性、高稳定性的非贵金属基催化剂,对电催化析氢的应用具有重要意义.以硫酸和植酸为硫磷掺杂剂,采用水热法合成了硫磷共掺杂石墨烯(SPG);随后,采用简单的醇热法制备了直接生长在SPG上的Ni基纳米材料(Ni/SPG).制备的Ni/SPG电催化剂表现出杰出的析氢性能,其阻抗极低(0.48Ω),电化学活性表面积极好...     

石墨烯基非贵金属燃料电池电催化剂研究进展

燃料电池具备高能量转化效率、高能量密度、广染料来源、低环境污染等优点成为新能源材料研究领域的热点课题。作为燃料电池的核心组成部分,催化剂的性能直接决定了燃料电池的使用价值。传统的Pt/C催化剂虽然具备较高的电催化活性,但相对有限的贵金属资源、相对较高的成本和相对较差的稳定性等问题严重限制了燃料电池的广泛应用。非贵金属材料具备一定的电催化活性、较好的耐蚀性和较低的成本,迅速成为继Pt/C催化剂后的下一代电催化剂。石墨烯具备优异的导电性、巨大的比表面和良好的化学稳定性,成为催化剂的理想载体。本文介绍了近年来石墨烯基非贵金属电催化剂的研究情况,归纳总结了目前燃料电池催化剂存在的相关问题,最后对燃料电池的发展前景进行了展望。     

PtMo合金催化剂氧还原反应催化性能研究

采用乙二醇还原法和后续的热处理工艺制备了Pt-Mo合金催化剂。使用透射电子显微镜、X射线衍射、电感耦合等离子体发射光谱、X射线光电子能谱等方法对样品进行了形貌、结构和组分的表征。通过电化学测试方法，探究了不同催化剂的电催化活性和稳定性。结果表明：合适的热处理温度不仅提高了Pt-Mo纳米颗粒的合金化程度，而且改变了催化剂颗粒表面的电子结构和成分。所以，经过400℃热处理的PtMo/C-400催化剂表现出较好的氧还原性能，其电催化活性和稳定性均与商业J01-Pt/C催化剂相当。     

水热合成镍铜复合磷化物及其电催化析氢与肼氧化性能

以镍网(NM, Nickel Mesh)为基体、NaH₂PO₂·H₂O为磷源、CuSO₄·5H₂O为铜源、NiSO₄·6H₂O为镍源, 采用一步水热法合成镍铜磷复合电催化剂, 对制备工艺进行优化, 并通过不同方法进行形貌、结构、组成和电催化性能表征。结果表明：当溶液中镍、铜、磷的配比为8: 1 :20时, 在140 ℃水热合成24 h, 制得主晶相为Ni₂P和Cu₃P、具有三级微纳结构的镍铜磷复合电催化剂。在电流密度为10 mA·cm ^-2时, NiCuP/NM的催化析氢及肼氧化过电势分别为165和49 mV; 在双电极体系中, 同电流密度下的分解槽压仅为0.750 V, 催化24 h后分解槽压几乎保持不变, 展现出优异的催化稳定性。无论三电极体系还是双电极体系均表现出优异的催化活性。分析认为, 电催化活性面积为空白镍网的近14倍, 为电催化过程提供了大量的活性位点; 掺入P改变了Ni、Cu原子的电子结构, 提高了材料的本征肼氧化活性, 两者的协同作用促进了电催化活性的提升。本研究为纳米尺度的合成提供了一个新的视角, 有望推动新型纳米孔结构材料在燃料电池和传感器应用中的发展。     

恒电位电沉积工艺参数对Pt-Ni合金催化剂性能的影响

与脉冲电沉积及恒流电沉积法相比,恒电位电沉积制备的电催化剂具有更优异的性能,目前很少用此法制备质子交换膜燃料电池用Pt-Ni合金催化剂。采用电化学还原法在多孔碳布及玻碳电极表面恒电位电沉积Pt-Ni合金催化剂。用X射线衍射(XRD)、能量色散谱(EDS)和扫描电镜(SEM)等对Pt-Ni合金催化剂的微观结构、组分和形貌进行了表征,并用循环伏安(CV)曲线评价了其电催化活性。研究了电沉积参数(沉积电位、电解液温度和沉积时间)对Pt-Ni合金催化剂的微观结构和电催化活性的影响。结果表明:沉积电位影响合金催化剂形核速度,引起微观结构不同,电解液温度影响着催化剂的成核和生长,沉积时间影响着Pt-Ni合金的沉积量;沉积电位为-0.35 V,电解液温度为50℃,沉积时间为15 min时,Pt-Ni合金催化剂均匀地分散于碳载体表面,粒径大约为11.9 nm,具有最大的电化学活性表面积(EASA),达44.19 m2/g,电催化活性最好。     

非贵金属基催化剂用于生物质电氧化高值化利用的研究进展（英文）

电催化在能源转换和化学品可持续生产领域具有广阔的应用前景.以生物质衍生物氧化反应替代传统的阳极析氧反应不仅能降低电催化系统的整体能耗,还能得到各种高附加值的氧化产物.高效的非贵金属基催化剂的设计和开发是生物质电氧化高值化利用中的难点和重点.针对目前已报道的生物质衍生物电氧化反应,本综述比较了电氧化法相比于传统方法的优势,介绍了具有代表性的非贵金属催化剂,并总结了相关的生物质衍生物氧化反应路径.结合目前报道的生物质衍生物电氧化反应机理,讨论了非贵金属基催化剂的构效关系以及催化剂的设计思路.最后,我们对用于生物质电氧化反应的非贵金属基催化剂的发展趋势和挑战进行了展望.     

反钙钛矿结构氮化铜纳米片实现高效电催化甲醇氧化转化为甲酸盐（英文）

钙钛矿氧化物具有灵活的组成和电子结构,在电催化水氧化反应中具有很大的应用潜力.然而,钙钛矿氧化物在电催化有机小分子转化中的应用研究较少,这可能是由于其导电性差,表面重构产生活性物种所需的能垒高.在本文中,我们报道了具有典型反钙钛矿结构的氮化铜纳米片作为甲醇选择性转化为甲酸盐的电催化剂,其形成甲酸盐的法拉第效率超过90%.原位电化学质谱和原位红外反射吸收光谱进一步证实了制备的氮化铜样品在较宽的电位范围内具有较高的甲酸盐选择性.此外,高分辨率透射电镜、X射线吸收光谱和原位拉曼光谱表明,该催化剂在电催化过程中发生表面重构形成了氧化态铜物种壳,从而提升了其整体甲醇氧化性能,而原始的氮化铜核则利于在催化剂内部的电子传递.本研究不仅为甲醇的高选择性转化提供了一种有意义的方案,而且为有机小分子的电化学转化提供了一种新型的非氧化物钙钛矿材料模型.     

石墨烯/金属氮杂环纳米复合材料在燃料电池分子氧催化还原反应中的应用研究

石墨烯具有良好的电子传导性、巨大的表面积、稳定的化学和机械稳定性等,在分子氧催化还原(ORR)反应中可以有效地改进催化剂的催化活性,是过渡金属大环催化剂新的基底材料。对石墨烯支持的非贵金属氮杂环复合材料在ORR催化反应中的应用以及影响催化O_2活性的因素进行了讨论。重点讨论了卟啉和酞菁中心金属核,Co和Fe,以及卟啉和酞菁作为N的前驱体对ORR电催化活性的影响,并展望了非贵金属氧还原催化剂在燃料电池中的研究发展方向。     

碳化钼电解水析氢催化剂的性能调控研究进展

氢气作为一种绿色、可持续的能源,有望代替传统的化石能源。电解水产氢是氢能可持续发展的理想途径。发展非贵金属电催化剂,提高电催化析氢反应(HER)效率,成为目前面临的主要问题。碳化钼因具有较好的电催化析氢活性和优异的稳定性,得到了广泛的关注。本文综述了近几年碳化钼电催化剂电解水产氢的研究进展,重点分析了提高其电催化析氢性能的一些方法,并对碳化钼的性能调控研究进行了展望。     

Heteroatom‐Doped Carbon Materials for Hydrazine Oxidation

The key in designing efficient direct liquid fuel cells (DLFCs), which can offer some solutions to society's grand challenges associated with sustainability and energy future, currently lies in the development of cost‐effective electrocatalysts. Among the many types of fuel cells, direct hydrazine fuel cells (DHFCs) are of particular interest, especially due to their high theoretical cell voltages and clean emission. However, DHFCs currently use noble‐metal‐based electrocatalysts, and the scarcity and high cost of noble metals are hindering these fuel cells from finding large‐scale practical applications. In order to replace noble‐metal‐based electrocatalysts with sustainable ones and help DHFCs become widely usable, great efforts are being made to develop stable heteroatom (e.g., B, N, O, P and S)‐doped carbon electrocatalysts, the activities of which are comparable to, or better than, those of noble metals. Here, the recent research progress and the advancements made on the development of heteroatom‐doped carbon materials, their general properties, their electrocatalytic activities toward the HzOR, and their dopant‐ and structure‐related electrocatalytic properties for the HzOR are summarized. Perspectives on the different directions that the research endeavors in this field need to take in the future and the challenges associated with DHFCs are included.     

Electronic Structure Evolution in Tricomponent Metal Phosphides with Reduced Activation Energy for Efficient Electrocatalytic Oxygen Evolution

Non‐noble metal catalysts for high‐active electrocatalytic oxygen evolution reaction (OER) are essential in large‐scale application for water splitting. Herein, tricomponent metal phosphides with hollow structures are synthesized from cobalt‐contained metal organic frameworks (MOFs), i.e., ZIF‐67, by tailoring the feeding ratios of Ni and Fe, followed by a high‐temperature reduction and a subsequent phosphidation process. Excellent OER activity and long‐time stability are achieved in 1 m NaOH aqueous solution, with an overpotential of 329 mV at 10 mA cm^?2 and Tafel slope of 48.2 mV dec^?1, even superior to the noble metal‐based catalyst. It is evidenced that the formed (oxyhydr)oxide/phosphate species by in situ electrochemical surface oxidation are responsible for active OER. Accordingly, the simultaneous introduction of external Ni and Fe elements significantly influences the electronic structures of the parent metal phosphides, leading to the in situ electrochemical formation of surface active layer with decreased OER activation energy for greatly improved water oxidation performance. This electronic structure tuning strategy by introducing multicomponent metals demonstrates a versatile method to use MOFs as precursors for synthesizing high‐efficient water splitting electrocatalysts.     

Design and Synthesis of Noble Metal-Based Alloy Electrocatalysts and Their Application in Hydrogen Evolution Reaction

Hydrogen energy is regarded as the ultimate energy source for future human society, and the preparation of hydrogen from water electrolysis is recognized as the most ideal way. One of the key factors to achieve large-scale hydrogen production by water splitting is the availability of highly active and stable electrocatalysts. Although non-precious metal electrocatalysts have made great strides in recent years, the best hydrogen evolution reaction (HER) electrocatalysts are still based on noble metals. Therefore, it is particularly important to improve the overall activity of the electrocatalysts while reducing the noble metals load. Alloying strategies can shoulder the burden of optimizing electrocatalysts cost and improving electrocatalysts performance. With this in mind, recent work on the application of noble metal-based alloy electrocatalysts in the field of hydrogen production from water electrolysis is summarized. In this review, first, the mechanism of HER is described; then, the current development of synthesis methods for alloy electrocatalysts is presented; finally, an example analysis of practical application studies on alloy electrocatalysts in hydrogen production is presented. In addition, at the end of this review, the prospects, opportunities, and challenges facing noble metal-based alloy electrocatalysts are tried to discuss.     

Fundamental aspects and recent advances in transition metal nitrides as electrocatalysts for hydrogen evolution reaction: A review

With increasing human population, sustainable energy production has become one of the most persistent and significant problems of the current century. Hydrogen is considered to be the best clean fuel for future energy requirements. As a substitute of fossil fuels, hydrogen is readily provided by an electrocatalytic hydrogen evolution reaction that splits water molecules. Conventional electrocatalysts based on noble metals are scarce and considerably expensive for large-scale hydrogen production, necessitating the search for low-cost earth abundant alternatives. In this context, transition metal nitrides have gained considerable attention as competent electrocatalytic materials for water splitting. This review presents recent advancements and progress on transition metal nitrides as efficient and cost-effective electrocatalysts for hydrogen production. After overviewing the fundamental aspects of the hydrogen evolution reaction (HER), the review discusses various synthetic strategies for developing transition metal nitrides. Discussed herein are titanium nitrides, vanadium nitrides, iron nitrides, nickel nitrides, molybdenum nitrides, tungsten nitrides, and their composite electrocatalysts employed in HER applications. Some design viewpoints for improving the electrocatalytic activity are systematically proposed. Finally, the review discusses challenges and future perspectives for the advancement of non-noble metal-based electrocatalysts.     

Noble‐Metal‐Free Electrocatalysts for Oxygen Evolution

Oxygen evolution reaction (OER) plays a vital role in many energy conversion and storage processes including electrochemical water splitting for the production of hydrogen and carbon dioxide reduction to value‐added chemicals. IrO₂ and RuO₂, known as the state‐of‐the‐art OER electrocatalysts, are severely limited by the high cost and low earth abundance of these noble metals. Developing noble‐metal‐free OER electrocatalysts with high performance has been in great demand. In this review, recent advances in the design and synthesis of noble‐metal‐free OER electrocatalysts including Ni, Co, Fe, Mn‐based hydroxides/oxyhydroxides, oxides, chalcogenides, nitrides, phosphides, and metal‐free compounds in alkaline, neutral as well as acidic electrolytes are summarized. Perspectives are also provided on the fabrication, evaluation of OER electrocatalysts and correlations between the structures of the electrocatalysts and their OER activities.     

Enhancement of the hydrogen evolution performance by finely tuning the morphology of Co-based catalyst without changing chemical composition

Nano Research - Transition-metal phosphides, as the promising alternatives to noble metal catalysts, have been widely used as efficient electrocatalysts for hydrogen evolution reaction (HER). In...     

Recent Progress in Graphene‐Based Noble‐Metal Nanocomposites for Electrocatalytic Applications

The fast industrialization process has led to global challenges in the energy crisis and environmental pollution, which might be solved with clean and renewable energy. Highly efficient electrochemical systems for clean‐energy collection require high‐performance electrocatalysts, including Au, Pt, Pd, Ru, etc. Graphene, a single‐layer 2D carbon nanosheet, possesses many intriguing properties, and has attracted tremendous research attention. Specifically, graphene and graphene derivatives have been utilized as templates for the synthesis of various noble‐metal nanocomposites, showing excellent performance in electrocatalytic‐energy‐conversion applications, such as the hydrogen evolution reaction and CO₂ reduction. Herein, the recent progress in graphene‐based noble‐metal nanocomposites is summarized, focusing on their synthetic methods and electrocatalytic applications. Furthermore, some personal insights on the challenges and possible future work in this research field are proposed.     

g-C3N4 encapsulated ZrO2 nanofibrous membrane decorated with CdS quantum dots: A hierarchically structured,self-supported electrocatalyst toward synergistic NH3 synthesis

The advancement of electrocatalytic N2 reduction reaction (NRR) toward ambient NH3 synthesis lies in the development of more affordable electrocatalysts than noble metals. Recently, various nanostructures of transition metal compounds have been proposed as effective electrocatalysts;however, they exist in the form of loose powders, which have to be immobilized on a matrix before serving as the electrode for electrolysis. The matrix, being it carbon paper, carbon cloth or metal foam, is electrocatalytically inactive, whose introduction inevitably raises the invalid weight while sacrificing the active sites of the electrode. Herein, we report on the fabrication of a flexible ZrO2 nanofibrous membrane as a novel, self-supported electrocatalyst. The heteroatom doping can not only endow the nanofibrous membrane with excellent flexibility, but also induce oxygen vacancies which are responsible for easier adsorption of N2 on the ZrO2 surface. To improve the electrocatalytic activity, a facile SILAR approach is employed to decorate it with CdS quantum dots (QDs), thereby tuning its Fermi level. To improve the conductivity, a g-C3N4 nanolayer is further deposited which is both conductive and active. The resulting hierarchically structured, self-supported electrocatalyst, consisting of g-C3N4 encapsulated ZrO2 nanofibrous membrane decorated with CdS QDs, integrates the merits of the three components, and exhibits a remarkable synergy toward NRR. Excellent NH3 yield of 6.32 × 10?10 mol·s?1cm?2 (?0.6 V vs. RHE) and Faradaic efficiency of 12.9% (?0.4 V vs. RHE) are attained in 0.1 M Na2SO4.     

Carbon‐Rich Nanomaterials: Fascinating Hydrogen and Oxygen Electrocatalysts

Hydrogen energy is commonly considered as a clean and sustainable alternative to the traditional fossil fuels. Toward universal utilization of hydrogen energy, developing high‐efficiency, low‐cost, and sustainable energy conversion technologies, especially water‐splitting electrolyzers and fuel cells, is of paramount significance. In order to enhance the energy conversion efficiency of the water‐splitting electrolyzers and fuel cells, earth‐abundant and stable electrocatalysts are essential for accelerating the sluggish kinetics of hydrogen and oxygen reactions. In the past decade, carbon‐rich nanomaterials have emerged as a promising class of hydrogen and oxygen electrocatalysts. Here, the development and electrocatalytic activity of various carbon‐rich materials, including metal‐free carbon, conjugated porous polymers, graphdiyne, covalent organic frameworks (COFs), atomic‐metal‐doped carbon, as well as metal–organic frameworks (MOFs), are demonstrated. In particular, the correlations between their porous nanostructures/electronic structures of active centers and electrocatalytic performances are emphatically discussed. Therefore, this review article guides the rational design and synthesis of high‐performance, metal‐free, and noble‐metal‐free carbon‐rich electrocatalysts and eventually advances the rapid development of water‐splitting electrolyzers and fuel cells toward practical applications.     

Ligand-Exchange-Induced Amorphization of Pd Nanomaterials for Highly Efficient Electrocatalytic Hydrogen Evolution Reaction

Various kinds of amorphous materials, such as transition metal dichalcogenides, metal oxides, and metal phosphates, have demonstrated superior electrocatalytic performance compared with their crystalline counterparts. Compared to other materials for electrocatalysis, noble metals exhibit intrinsically high activity and excellent durability. However, it is still very challenging to prepare amorphous noble-metal nanomaterials due to the strong interatomic metallic bonding. Herein, the discovery of a unique thiol molecule is reported, namely bismuthiol I, which can induce the transformation of Pd nanomaterials from face-centered-cubic (fcc) phase into amorphous phase without destroying their integrity. This ligand-induced amorphization is realized by post-synthetic ligand exchange under ambient conditions, and is applicable to fcc Pd nanomaterials with different capping ligands. Importantly, the obtained amorphous Pd nanoparticles exhibit remarkably enhanced activity and excellent stability toward electrocatalytic hydrogen evolution in acidic solution. This work provides a facile and effective method for preparing amorphous Pd nanomaterials, and demonstrates their promising electrocatalytic application.