过渡族金属及其化合物碱性电解水析氧催化剂研究进展

该文主要从电解水制氢技术的发展现状、电解水析氧机理以及析氧催化材料等方面进行探讨和分析,通过过渡族金属元素催化材料OER性能的分析,对催化剂设计和制备中存在的不足进行深入地探讨,为低成本、高性能的催化剂材料开发提供依据。     

双金属Ni-Co基析氧反应电催化剂研究进展

目的  能源消耗的持续增长和化石燃料燃烧带来的环保和能源安全问题已经引起世界各国的广泛关注。因此,发展清洁能源生产技术已成为世界范围内的主要研究重点。氢能具有无污染、比能密度高、资源丰富等特点,是最具潜力的传统化石燃料替代品之一。电催化分解水被认为是最有希望的制氢方法,但阳极上的析氧反应动力学缓慢,能量转换效率低,是大规模制氢的主要瓶颈。与稀有和昂贵的贵金属催化剂相比,镍-钴（Ni-Co）基电催化剂由于具有可调的电子结构、高导电性和低成本优势,有望在碱性溶液中实现卓越的OER活性和耐久性。 方法  文章总结并讨论了在OER中Ni-Co基电催化剂的最新研究发展。重点讨论了Ni-Co基电催化剂的设计和合成,以及在OER过程中提高其电催化性能的研究策略。 结果  为了代替钌、铱等贵金属催化剂,研究者们对Ni-Co基非贵金属催化剂进行了大量研究。包括氧化物、氢氧化物、合金、氮化物、硫化物、磷化物等在内的多种Ni-Co基催化剂通过化学结构的调控,从阳极角度提高了电催化制氢的活性。但这些催化剂又分别面临不同的缺陷,有待进一步研究克服。 结论  开发具有高OER活性的非贵金属催化剂是降低电解水制氢成本,促进氢能产业发展的重要途径。虽然仍有一些技术问题尚未解决限制了Ni-Co基催化剂替代贵金属催化剂,但作为重要的贵金属催化剂替代品,Ni-Co基催化剂的研究为新型催化剂的开发提供了重要选择。     

质子交换膜燃料电池非贵金属催化剂研究进展

贵金属铂（Pt）基催化剂价格昂贵且易中毒,这是造成质子交换膜燃料电池难以大规模商业化的主要原因,而非贵金属催化剂有望替代Pt基催化剂来解决这一难题。本文综述了最近几年非贵金属催化剂在质子交换膜燃料电池中应用的研究进展,并提出了今后的研究重点和方向。     

限域型贵金属氧还原反应电催化剂研究进展北大核心CSCD

开发高效的氧还原反应电催化剂是实现质子交换膜燃料电池规模化应用的关键技术之一。目前常用的贵金属催化剂成本较高,并且稳定性仍需改善。物理限域是改善催化剂稳定性的有效策略,在不影响贵金属催化剂催化活性的前提下,物理限域层不仅可以抑制催化剂的烧结,还能够减少催化剂在反应过程中的团聚、脱落以及溶解等问题,从而提升催化剂的寿命。本文回顾了近年来用于电催化氧还原反应的限域型贵金属催化剂,主要包括导电聚合物限域、非金属氧化物限域、金属氧化物限域以及碳层限域的贵金属催化剂。根据限域层制备策略不同,重点分析了限域层的孔结构、导电性、致密性、抗腐蚀性与催化剂性能之间的构效关系。着重介绍了实现碳层限域的三种策略,包括“沉积-转化”、“嵌入-转化”以及“一步热解”。分析表明,通过构筑具有丰富孔结构、高导电性及合适厚度的限域层能够在保证活性的同时显著提升催化剂稳定性。最后对全文进行了总结并对当前存在的问题进行了整理,同时对未来限域型催化剂的发展进行了展望。     

原位电解合成Ni-B析氧催化剂及其性能研究

以ITO玻片作为基体,在常温常压下采用原位电沉积法制备了Ni-B析氧催化剂。考察了K2B4O7溶液的浓度、温度以及pH值对催化剂的影响和电极反应的Faradaic效率,并通过循环伏安曲线和Tafel曲线考察了Ni-B催化剂的电化学性能,采用XRD、SEM和EDS等分析技术对催化剂的结构、形貌以及组成进行了表征。实验结果表明:原位电解沉积合成的Ni-B析氧催化剂在电解水过程中表现出较高的析氧活性和稳定性,在1mA/cm2电流密度时的析氧过电位约为0.31V。     

锌空气电池非贵金属双功能阴极催化剂研究进展

锌空气电池是一种特殊的燃料电池,以空气中的氧气作为阴极反应活性物质,具有理论能量密度高、安全便携以及绿色无污染等优点,是柔性可穿戴光电子产品的理想供电电源之一.电化学氧还原反应(ORR)和氧析出反应(OER)对于锌空气电池的性能起着至关重要的作用.目前,在碱性介质中贵金属Pt具有最高的ORR催化活性,Ir和Ru及其氧化...     

非铂燃料电池催化剂研究进展

燃料电池是利用氢能的理想途径,但燃料电池对于铂催化剂的依赖限制了其发展。该文综述了近年来非铂燃料电池催化剂的研究进展。对于质子交换膜燃料电池,因为阳极需铂量低,相关研究主要集中在阴极催化剂上。对于碱性膜燃料电池,一些非贵金属催化剂在阴极展现出较高的活性,但阳极侧动力学缓慢,因此非铂催化剂的研究在两极均有开展。最后,对非铂燃料电池催化剂当前的研究重点和未来的发展方向进行总结和展望,旨在为非铂燃料电池催化剂的研究和长远发展提供指导和参考。     

单原子催化剂在氢燃料电池阴极氧还原反应中的研究进展

氢燃料电池是一种高效、环境友好以及零碳排放的能量转化技术,然而高成本的贵金属催化剂阻碍了其规模化应用。单原子催化剂因具有高原子利用率、高催化活性和选择性、低成本等优点,对氧分子表现出优异的催化还原性能,在氢燃料电池中具有广阔的应用前景。如何设计合成高效和低成本的单原子催化剂成为该领域的研究热点。重点综述贵金属单原子催化剂和非贵金属单原子催化剂在氢燃料电池阴极氧还原反应中的研究进展,总结提出增强单原子催化剂氧还原性能的调控策略,包括配位结构、局域环境、双原子对、缺陷位点以及暴露活性位点等调控机制,为从原子尺度设计高效氧还原催化剂提供了思路借鉴,并对氢燃料电池氧还原单原子催化剂的发展机遇与挑战进行了展望。     

当前实用和未来发展Pt-非Pt氧还原电催化剂研究进展

燃料电池阴极侧氧还原反应由于其迟缓的动力学,使得贵金属铂成为最为高效的电催化剂,成本高昂,限制燃料电池规模化应用。开发低成本、高性能、可实用氧还原电催化剂尤为重要。基于课题组多年在实用化燃料电池氧还原电催化剂的研究情况,综述面向当前实用和未来发展的铂-非铂电催化剂的研究进展。重点介绍实用化高载量、高活性、高结构稳定性铂基电催化剂合成策略以及在燃料电池膜电极中的性能高效表达,同时阐述非铂碳基催化剂理性设计、可控制备。此外,对该研究方向的发展进行展望,以期加速燃料电池关键材料国产化。     

贵金属比例对燃气发动机三元催化剂性能的影响

以燃气发动机用三元催化剂为研究对象,通过模拟配气的方式,在催化剂小样测试台上进行CH_4、CO、NO_x的起燃性能、水热老化性能及不同空燃比窗口下的性能测试,研究贵金属总质量相同时不同贵金属比例对于三元催化剂性能的影响。研究发现,在相同试验条件下,三元催化剂中含有一定比例Pt对CH_4和NOx的转化效率有一定的促进作用,对于CO转化效率无明显影响;在抗老化性方面,Pt/Pd/Rh型催化剂在CH_4和NO_x的转化效率上较Pd/Rh型催化剂劣化严重,但在NO_x转化效率上劣化较小;Pt能够提升三元催化剂降低NO_x排放能力; Pt/Pd/Rh型催化剂较Pd/Rh型催化剂有着更宽广的反应窗口。     

In situ synthesis of a novel organic-inorganic composite as a non-noble metal electrocatalyst for the oxygen evolution reaction

Offering new techniques for efficient design and fabrication of inexpensive and earth-abundant catalysts for the development of oxygen evolution electrodes is a fundamental approach to promote sustainable energy processes. Herein, we report the in situ synthesis of a novel organic-inorganic composite directly onto carbon paste electrode (CPE) surface, as a robust substrate to incorporate Nickel-Iron (Ni-Fe) metal ions without using any binders or energy consumer techniques. Polyoxometalate (POM) and o-Anisidine (oA) are composite components that can be easily combined on the electrode surface (oA-POM/CPE). Ascribed to the synergy of context and metal ions, the as-prepared electrode affords a high catalytic activity and stability towards oxygen evolution reaction (OER), and gained a current density of 10 mA cm^?2 at overpotential of 330 mV. Moreover, the distinct electrocatalytic activity is illustrated by varying the amount of Fe in immersion solution, which proves the change made in percentage ratio of Ni-Fe in immersion solution that consequently affects Ni-Fe percentage value on electrode surface. This represents the competition between metal cations in creating complex with composite. Collectively, this simple strategy provides a promising way for the development of effective and non-noble metal-based OER electrocatalysts.     

Electrochemically fabricated NiCu alloy catalysts for hydrogen production in alkaline water electrolysis

NiCu alloy catalysts for alkaline water electrolysis were prepared by an electrodeposition method varying the alloy composition. When the deposition potential became more positive, the bulk and surface Cu content in NiCu alloys as well as the catalyst particle size gradually increased, which were confirmed by various spectroscopic and electrochemical techniques. The surface coverage of the catalysts was found to be a function of the deposition potential, as well. The catalytic activities of the prepared NiCu alloys to hydrogen evolution reaction (HER) were investigated with cyclic voltammetry in a 6.0 M KOH electrolyte at 298 K, and the mass activities of NiCu alloys were correlated with bulk and surface Cu contents to investigate the Cu alloying effect.     

Highly stable and efficient non-precious metal electrocatalysts of Mo-doped NiOOH nanosheets for oxygen evolution reaction

Active and stable electrocatalysts for oxygen evolution reaction (OER) made from earth-abundant elements are highly attractive. Herein, we report our recent efforts in developing Mo-doped NiOOH (MoNiOOH) nanosheets as highly active and stable OER catalysts. The doping of Mo is found to be conducive for both activity and stability. The MoNiOOH nanosheets need overpotential of only 390 mV to afford the current densities of 100 mA cm^?2 and show no obvious degradation under steady-state current density of 100 mA cm^?2 even after 24 h.     

Ultrashort pulse laser-structured nickel surfaces as hydrogen evolution electrodes for alkaline water electrolysis

In this study, we report on micro- and nanostructured Ni surfaces produced by an ultrashort pulse laser process as cathode materials for the alkaline electrolysis of water. We studied the influence of the laser-induced microstructure and surface morphology as well as a cyclic voltammetric activation process on the electrochemical activity of the hydrogen evolution reaction. Galvanostatic techniques, steady-state polarization curves to attain Tafel parameters and capacitance calculations via electrochemical impedance spectroscopy were used to analyze the electrodes. The analyses reveal that the ultrashort pulse laser process increases the specific surface on formerly flat Ni surfaces. Further, the cyclic voltammetric activation process gives rise to an increased intrinsic activity. Both effects lead to a strongly reduced overpotential value. This work demonstrates that different processes can be combined to dramatically boost the activity of Ni electrodes for the hydrogen evolution reaction.     

Synthesis and characterization of electrocatalysts for the oxygen evolution in PEM water electrolysis

IrO₂, Ir_xSn_(1−x)O₂ (x = 0.7, 0.5) and Ir_xRu_(1−x)O₂ (x = 0.7, 0.5) electrocatalysts for the oxygen evolution reaction (OER) have been synthesized using the Adams fusion method. The metal oxides were characterized via X-ray diffraction, scanning electron microscopy, inductively coupled plasma-atomic emission spectrometry and nitrogen adsorption-desorption measurements to have information about their crystallographic structure, chemical composition and morphology, respectively. A controlled bulk molar fraction of Ru or Sn was introduced in the IrO₂ lattice during the synthesis with no phase separation. The electrocatalytic activity of the synthesized oxides in the OER was studied in liquid electrolyte using porous rotating-disk electrodes, in “half-cell” configuration and in a 5 cm² proton-exchange membrane water electrolysis cell. An increase of the electrical performance was observed upon Ru insertion and a severe depreciation upon Sn insertion.     

Investigation of V-doped TiO2 as an anodic catalyst support for SPE water electrolysis

A modified evaporation-induced self-assembly (EISA) method was employed to prepare titania samples doped with different amounts of vanadium (0, 10, 20, 30 at.%), which were further evaluated as catalyst supports for the oxygen evolution reaction (OER) catalyst IrO₂ in the solid polymer electrolyte water electrolyzer (SPEWE). The effects of V dopant on titania supports are proved to be twofold: i) enhancing the simplification of phase composition and consequently improving the homogeneity of porous morphology; ii) introducing redox couple V (IV)/V (V) to the surface of titania. As a result, the catalyst's OER activity is improved with the increase of V dopant in the titania support after loading IrO₂ via Adams fusion method. In single cells, the OER performance gradually increases with V dopant from 0 to 20 at.%, followed by a performance deterioration with V amount reaching 30 at.% due to the corrodible V₂O₅ precipitate.     

Synthesis and characterization of novel high-performance composite electrocatalysts for the oxygen evolution in solid polymer electrolyte (SPE) water electrolysis

Novel Ru_0.3Ir_0.7O₂/Pt_0.15 composite electrocatalysts for the oxygen evolution in solid polymer electrolyte (SPE) water electrolysis were prepared by a two-step method. The intermediate Pt black with or without heat treatment (the final samples marked as C₁ and C₂ respectively) was firstly synthesized by a conventional reduction method with ultrasonic dispersion. The composite electrocatalysts were then prepared by impregnation-reduction method with ultrasonic dispersion followed by fusion treatment. The influence of heat treatment of intermediate Pt black on the properties of the composites was explored. The as-prepared composites were characterized by XRD, BET, SEM, EDX, CV and LP. The catalytic performance of the as-prepared electrocatalysts has also been investigated in a 20 cm² SPE electrolytic cell using Nafion^® 117 as an electrolyte with the loading of noble metals of 1.8 mg cm⁻² at anode and 0.3 mg cm⁻² at cathode. It shows that the catalytic performance of samples C₁ and C₂ is obviously higher than that of commercial PtIrO₂ electrocatalyst and the catalytic activity of C₁ electrocatalyst for the oxygen evolution is evidently higher than that of C₂ electrocatalyst in the whole range of cell voltage. The cell voltage was only 1.76 V and 1.90 V when the current density is 1.0 A cm⁻² and 1.5 A cm⁻² respectively using sample C₁ as anode electrocatalyst.     

IrO2-graphene hybrid as an active oxygen evolution catalyst for water electrolysis

In the present work, graphene supported IrO₂ catalyst (IrO₂/RGO) has been synthesized by hydrothermal method in ethanol/water mixture solvent. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests reveal that IrO₂ is uniformly supported on RGO surface with ultrafine IrO₂ nanoparticles (ca. 1.7 nm). Linear sweep voltammetry (LSV) tests indicate that the catalytic activity of IrO₂/RGO hybrid towards oxygen evolution reaction (OER) is 2.3 times that of commercial IrO₂. The superior OER activity of IrO₂/RGO hybrid is attributed to the enhanced surface area and the improved electrical conductivity of IrO₂ due to the introduction of graphene support. Lifetime tests demonstrate that IrO₂/RGO hybrid has unexpectedly high OER durability. It also displays an excellent performance in long-time water electrolysis. This may be interpreted in terms of the dispersion retention of IrO₂ nanoparticles on RGO surface, which is caused by the interaction between IrO₂ and Π-electrons of RGO.     

Eco-designed electrocatalysts for water splitting: A path toward carbon neutrality

Realizing sustainable hydrogen fuel production through water electrolysis is crucial to achieving carbon neutrality. However, the development of cost-effective electrocatalysts continues to be a challenge. Eco-designed electrocatalysts derived from wastes and naturally abundant materials have recently received increasing attention. The development of eco-designed electrocatalysts is of great environmental and economic significance and makes green hydrogen more accessible to the wider community. Here, recent advances in eco-designed electrocatalysts for water splitting are summarized. Eco-design strategies such as pyrolysis, ball milling, wet-chemical methods, and electrochemical treatment are first analyzed. Recent achievements in eco-designed electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting (OWS) are then detailed, with an emphasis on analyzing the eco-design strategy-catalyst property-catalytic performance correlation. Perspectives in this blooming field for a greener hydrogen economy are finally outlined.