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。     

二维超导η-Mo3C2薄膜的可控制备

二维超导体具有丰富的物理特性和非常广泛的潜在应用.最近,有报道制备出具有二维超导特性的α-Mo2C和面心立方Mo2C,这些材料为碳基超导的研究带来了新的方向.碳化钼具有多种晶体结构,除了目前已经被制备的种类外,二维碳化钼尚没有新的晶体结构被制备出来,这或许是因为在制备过程中缺乏额外的能量供给.在本工作中,我们进一步发展...     

过渡金属磷化物用于电解水析氢反应的研究进展

氢能是一种很有发展前景的可替代化石燃料的清洁能源,电解水制氢技术是最有希望实现能源可持续发展和零排放的制氢途径,而设计开发储量丰富、成本低廉以及高效稳定的电催化剂是电解水高效制氢的关键。过渡金属磷化物(TMPs)作为一种非贵金属催化剂,因具有天然丰度高、成本低、导电性好以及催化性能稳定等优势,近年来被广泛应用于电解水析氢反应的研究领域。概述了电解水析氢反应机理,介绍了TMPs的制备方法、常见的改性方法及其在电解水析氢反应中的应用,总结了TMPs电催化剂目前所存在的问题和面临的挑战并对其进行了展望。     

电沉积法制备含钼合金的研究进展

含钼合金具有较高的硬度、优异的耐磨耐腐蚀性能和催化析氢性能,作为涂层和电极材料在金属防护、电解水制氢等领域得到了广泛的应用。电沉积法具有沉积速度快、沉积镀层致密及产物种类多等优点,是制备含钼合金的重要技术之一。早期电沉积法用于制备二元含钼合金,对其电沉积工艺及机理的研究较为深入,但通过调整工艺参数的方法对二元含钼合金性能的提高仍旧有限。为了改善二元含钼合金的性能,添加合金元素制备多元含钼合金以及添加粒子制备粒子掺杂含钼合金成为近年的研究热点和趋势。多元含钼合金中添加的元素主要包括C、Fe、P、W、Cr等,能有效改善其不同方面的性能。改善催化析氢性能的元素有C、Zn、Sn、S、Fe、P等,其机理在于它们与铁族元素和钼元素能产生协同作用;提高显微硬度和耐磨耐腐蚀性能的元素有W、Cr、P等,其机理在于它们能改变合金结构,造成晶格畸变。粒子掺杂含钼合金中添加的粒子主要有ZrO₂、TiO₂、SiC、TiN等,能显著改善合金的显微硬度和耐磨耐腐蚀性能,这是因为纳米颗粒能在合金基质中弥散分布,起到细化晶粒及阻碍位错运动的作用。近两年,磁场、超声波辅助电沉积...     

碱性电解水制氢的活性阴极材料

电解水制氢是实现大规模制氢的重要手段，本文就几种基本非贵金属析氢反应活性合金的合成方法，析氢反应催化性能以及它们作为析氢反应负极材料所表现出的优缺点作了简要评述。     

负载Pt纳米颗粒的掺氮碳化钼微球催化电解水析氢

电解水制氢是极具发展应用前景的绿色技术,使用低成本碳材料负载贵金属作为催化剂基底,是减小析氢催化剂贵金属负载量和优化其性能的有效手段。采用配位聚合法,通过调控pH得到了由纳米片自组装形成的具有高比表面积的前驱体微球,再通过离子交换和高温焙烧将Pt纳米颗粒均匀负载在氮掺杂碳化钼表面,制备出了Pt/N-Mo₂C NFs。因Pt纳米颗粒具有多层级结构的N-Mo₂C上的高度分散以及Pt与N-Mo₂C基底之间的协同作用,它展现出十分优异的析氢性能。Pt/N-Mo₂C NFs拥有较低的过电位(44 mV/η₁₀和137 mV/η₁₀₀),和Tafel斜率为46.2 mV/dec,同时具有良好的稳定性。研究结果对于设计低负载量的贵金属催化剂具有一定的借鉴意义。     

电化学刻蚀制备表面纳米多孔NiMoCu电解水析氢催化剂

电解水制氢是一项制取绿色氢能的重要技术,开发高催化活性的催化剂作为电极材料是当前的研究热点。电解水反应包括阴极的析氢反应和阳极的析氧反应,以Ni₇₄Mo₆Cu₂₀三元合金条带为前驱体,采用电化学脱合金技术制备了一种用于析氢反应的表面纳米多孔NiMoCu电解水析氢催化剂,并采用扫描式电子显微镜、X射线衍射仪、X射线光电子能谱仪等设备对材料的物理化学特性进行了表征。结果表明：所制备的纳米多孔NiMoCu电极材料在1mol/L KOH溶液中具有良好的析氢性能,仅需要90mV、227mV的过电位就能达到10mA/cm²、100mA/cm²的电流密度。     

二硫化钼在电催化析氢反应中的应用进展

氢气因清洁和可再生等优点，被认为是一种具有发展前景的清洁能源，在未来替代传统化石燃料的可再生能源体系中具有重要地位。电化学分解水是一种高效且环境友好的制氢途径，在电解水制氢技术的发展中，高效电催化析氢催化剂的作用显得尤为重要。二硫化钼(MoS₂)具有较低的析氢吉布斯自由能及耐酸碱腐蚀等优点，因此，MoS₂作为高效的电催化析氢催化剂一直是研究热点。阐述了MoS₂的电催化析氢机理，综述了不同形貌MoS₂在电催化析氢中的应用，通过对MoS₂电催化剂进行改性来优化其催化活性。研究表明通过改善MoS₂边缘位点的催化活性、增加活性位点的数量等方法能够极大地改善MoS₂电化学析氢过程中的催化活性。     

碳化钼基析氢反应电催化剂的制备及改性研究进展

碳化钼(Mo₂C)因其与铂(Pt)相似的d带电子结构、宽pH适用性、易于合成、低成本等优势，成为一种很有前途的电催化剂。然而，纯Mo₂C存在导电性差、界面反应动力学慢、Mo-H结合能太强等缺陷。近年来，许多研究报道了改性Mo₂C基催化剂来提升其电催化析氢性能，基于此，综述了Mo₂C常用的制备工艺以及提高Mo₂C析氢性能的各种不同改性策略，深入分析了不同改性方式对Mo₂C析氢性能提高的内在原因。最后，提出了Mo₂C基电催化剂目前面临的挑战和未来的发展方向。     

钌基催化剂的制备及其析氢性能的研究

电化学水分解制氢是一种极具发展前景的无污染制氢方法。设计一种价格低廉,并且具有高效催化性能的催化剂对缓解环境压力,以及对电催化析氢的大规模应用具有重要意义。以松果壳(PC)为生物质碳前驱体,尿素为氮源,RuCl₃为钌源,通过水热和高温碳化的方法将Ru锚定在氮掺杂的生物质衍生碳基底上(Ru-N-CPC)。Ru-N-CPC具有良好的电化学性能(61 mV的过电位就可达到10 mA cm^-2,1 mol/L KOH)和稳定性。采用一系列测试表明催化剂具有良好的电化学性能可归因于氮的掺杂导致了大量的缺陷产生,从而使Ru能够顺利地、均匀地被载于碳材料上,同时由于Ru和N的协同作用,促使催化析氢反应的活性提高。     

固体聚合物电解质水电解催化剂的研究进展

鉴于固体聚合物电解质(SPE)水电解技术的发展现状,着重介绍了目前在SPE水电解析氢、析氧催化剂方面的研究进展,对催化剂的制备方法进行了分析,并对近来以纳米氮化钛粉体为前驱体通过浸渍—热分解法制备水电解催化剂的研究工作进行了总结,提出了开发高耐蚀性的催化剂载体和降低贵金属载量是SPE水电解催化剂的重要发展方向。     

基于电催化析氧反应的非贵金属催化剂研究进展

在全球变暖和能源危机的背景下，能源问题已成为全球各国战略安全的重要组成部分。氢能作为可持续的新型可再生清洁能源，对缓解全球性能源短缺具有重要意义。在众多制氢候选方案中，电解水制备氢气被认为是最可靠、最可行的途径之一。但在电解过程中，反应动力学极为迟缓的阳极析氧反应(Oxygen evolution reaction,OER)严重制约着整体反应效率。因此，开发成本相对低廉、催化剂性能优异、耐久性好的高效OER电催化剂，从而提高电解水制氢工艺技术的能源转换效果受到了广泛关注。本文首先简要阐述了析氧反应的反应机制及其性能的评价参数，接着对非贵金属催化剂的研究进行分类讨论，并列举了提高催化性能的策略和方法，最后对设计新型催化剂进行展望。     

层状双氢氧化物析氧催化剂的研究进展

层状双氢氧化物具有制备简单,层间客体可调节,合成成本较低,稳定性较好等优点,因此成为析氧催化剂的研究热点,但仍存在电荷传输速率低,过电位相对较高等问题,因此需要对其改性来加快其大规模应用。首先介绍了层状双氢氧化物的结构特点,简述了其析氧反应的催化机理,然后总结了不同种类的优化改性策略来增强其催化活性。优化改性方法分别包括:与导电基材复合;合成超薄纳米片法;与石墨烯复合法;杂化改性法。重点探讨了层状双氢氧化物析氧催化剂在电解水制氢方面的应用,提出了不同改性方法的优缺点,阐明将其适当结合,有利于制备更高效的析氧催化剂,最后指出了这类催化剂仍面临的问题:回收率较低,催化剂稳定性和可实现的电流密度尚未达到工业化需求,无法实现大规模制备等难点。     

NiFe-植酸复合物的室温制备及其全解水电催化性能

制备高稳定性、高活性双功能催化剂用于全解水制氢是氢能源大规模商业化应用的重要环节之一。本文以植酸(PA)、六水合氯化铁(FeCl₃·6H₂O)和六水合氯化镍(NiCl₂·6H₂O)为原料,采用两步室温浸渍法在泡沫镍(NF)上制备了片状无定形植酸-镍铁双金属复合材料(NiFe-PA)。采用线性扫描伏安法(LSV)考察了NiFe-PA修饰NF电极(NiFe-PA/NF)在碱性条件(1.0 mol/L KOH)的电解水催化性能。实验结果表明：由于NiFe双金属之间的协同效应,NiFe-PA/NF作为双功能催化剂显示出优越的析氧和析氢性能。NiFe-PA/NF电极在50 mA·cm^-2电流密度下析氧反应的过电位仅需220 mV;在10 mA·cm^-2电流密度下的析氢反应的过电位为135 mV。将NiFe-PA/NF组装成双电极系统用于全解水,达到10 mA·cm^-2电流密度的电池电压仅需1.61 V,低于贵金属催化剂体系RuO₂     

Synergistic Nanotubular Copper‐Doped Nickel Catalysts for Hydrogen Evolution Reactions

Developing highly active electrocatalysts with low cost and high efficiency for hydrogen evolution reactions (HERs) is of great significance for industrial water electrolysis. Herein, a 3D hierarchically structured nanotubular copper‐doped nickel catalyst on nickel foam (NF) for HER is reported, denoted as Ni(Cu), via facile electrodeposition and selective electrochemical dealloying. The as‐prepared Ni(Cu)/NF electrode holds superlarge electrochemical active surface area and exhibits Pt‐like electrocatalytic activity for HER, displaying an overpotential of merely 27 mV to achieve a current density of 10 mA cm^?2 and an extremely small Tafel slope of 33.3 mV dec^?1 in 1 m KOH solution. The Ni(Cu)/NF electrode also shows excellent durability and robustness in both continuous and intermittent bulk water electrolysis. Density functional theory calculations suggest that Cu substitution and the formation of NiO on the surface leads to more optimal free energy for hydrogen adsorption. The lattice distortion of Ni caused by Cu substitution, the increased interfacial activity induced by surface oxidation of nanoporous Ni, and numerous active sites at Ni atom offered by the 3D hierarchical porous structure, all contribute to the dramatically enhanced catalytic performance. Benefiting from the facile, scalable preparation method, this highly efficient and robust Ni(Cu)/NF electrocatalyst holds great promise for industrial water–alkali electrolysis.     

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.     

Sponge-like nickel phosphide–carbon nanotube hybrid electrodes for efficient hydrogen evolution over a wide pH range

Cost-effective hydrogen production via electrolysis of water requires efficient and durable earth-abundant catalysts for the hydrogen evolution reaction (HER) over a wide pH range.Herein,we report sponge-like nickel phosphidecarbon nanotube (NixP/CNT) hybrid electrodes that were prepared by facile cyclic voltammetric deposition of amorphous NixP catalysts onto the threedimensional (3D) porous CNT support.These compounds exhibit superior catalytic activity for sustained hydrogen evolution in acidic,neutral,and basic media.In particular,the NixP/CNT electrodes generate cathodic currents of 10 and 100 mA.cm-2 at overpotentials of 105 and 226 mV,respectively,in a 1 M phosphate buffer solution (pH =6.5) with a Tafel slope of 100 mV·dec-1;the currents were stable for over 110 h without obvious decay.Our results suggest that the 3D porous CNT electrode supports could serve as a general platform for earth-abundant HER catalysts for the development of highly efficient electrodes for hydrogen production.     

A Robust Nonprecious CuFe Composite as a Highly Efficient Bifunctional Catalyst for Overall Electrochemical Water Splitting

To generate hydrogen, which is a clean energy carrier, a combination of electrolysis and renewable energy sources is desirable. In particular, for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in electrolysis, it is necessary to develop nonprecious, efficient, and durable catalysts. A robust nonprecious copper–iron (CuFe) bimetallic composite is reported that can be used as a highly efficient bifunctional catalyst for overall water splitting in an alkaline medium. The catalyst exhibits outstanding OER and HER activity, and very low OER and HER overpotentials (218 and 158 mV, respectively) are necessary to attain a current density of 10 mA cm^?2. When used in a two‐electrode water electrolyzer system for overall water splitting, it not only achieves high durability (even at a very high current density of 100 mA cm^?2) but also reduces the potential required to split water into oxygen and hydrogen at 10 mA cm^?2 to 1.64 V for 100 h of continuous operation.     

Electronic Structure Modulation of Nickel Sites by Cationic Heterostructures to Optimize Ethanol Electrooxidation Activity in Alkaline Solution

It is a good idea for efficient production of hydrogen to use ethanol oxidation reaction (EOR) in place of oxygen evolution reaction (OER) in water electrolysis process. Ni-based non-precious electrocatalysts are widely used in the conversion of ethanol to acetic acid. Here, different selenide heterostructures (NiCoSe, NiFeSe, and NiCuSe) are prepared in which Ni sites are regulated by transition metal. The valence state of Ni is NiCuSe < NiCoSe < NiFeSe in the three heterojunctions. NiCoSe shows the optimized charge distribution of Ni sites and outstanding catalytic activity. The effective modulations lead to optimized d-band center and facilitates both adsorption and desorption of reaction intermediates, which improves the kinetics of EOR. The results of this work prove that with appropriate designed catalyst it is possible to replace kinetically slow OER with faster EOR in water electrolysis to produce hydrogen.     

In Situ Derived CoB Nanoarray: A High‐Efficiency and Durable 3D Bifunctional Electrocatalyst for Overall Alkaline Water Splitting

The development of efficient bifunctional catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of extreme importance for future renewable energy systems. This Communication reports the recent finding that room‐temperature treatment of CoO nanowire array on Ti mesh by NaBH₄ in alkaline media leads to in situ development of Co?B nanoparticles on nanowire surface. The resulting self‐supported Co?B@CoO nanoarray behaves as a 3D bifunctional electrocatalyst with high activity and durability for both HER (<17% current density degradation after 20 h electrolysis) and OER (<14% current density degradation after 20 h electrolysis) with the need of the overpotentials of 102 and 290 mV to drive 50 mA cm^?2 in 1.0 m KOH, respectively. Moreover, its two‐electrode alkaline water electrolyzer also shows remarkably high durability and only demands a cell voltage of 1.67 V to deliver 50 mA cm^?2 water‐splitting current with a current density retention of 81% after 20 h electrolysis. This work provides a promising methodology for the designing and fabricating of metal‐boride based nanoarray as a high‐active water‐splitting catalyst electrode for applications.