Recent Progress in Precious Metal-Free Carbon-Based Materials towards the Oxygen Reduction Reaction: Activity,Stability, and Anti-Poisoning

The large-scale application of polymer electrolyte membrane fuel cells (PEMFCs) depends heavily on the development of high-performance and cost-effective oxygen reduction reaction (ORR) electrocatalysts to replace the traditional Pt-based materials. Among the numerous candidates of ORR electrocatalysts, precious metal-free carbon-based materials have received ever-increasing attention for their unique electronic features, tunable nanostructures, and robustness. Although tremendous efforts have been devoted to raising the intrinsic properties of precious metal-free carbon-based materials, there exists a lot of room for them to be improved in activity, stability, and poison-tolerance. In this Minireview, the latest strategies for enhancing activity by increasing the accessible active sites and promoting the intrinsic activity have been summarized. In addition, with special emphasis on devastating catalyst poisoning, up-to-data tactics for elevating the stability and poison-tolerance are introduced. Finally, conclusions and perspectives are also presented.     

非水系锂空气电池碳基正极材料

锂空气电池因其极高的理论能量密度和环境友好等优点,有望成为下一代车用动力电源体系。然而,目前锂空气电池尚存在许多的问题和挑战,就正极而言,空气电极活性低的问题已成为制约锂空气电池技术发展最为重要的问题,因此,开发高性能锂空气电池正极催化剂一直以来都是该领域的重要研究课题。碳基催化剂(正极材料)是目前最具吸引力的锂空气电池正极材料之一,近年来得到了广泛的关注和研究。本文总结和介绍了近年来国内外在多孔碳基材料、石墨烯基材料、掺杂碳材料等碳材料作为锂空气电池正极材料方面的进展,包括本课题组在非水系锂空气电池正极材料方面的研究工作,并对碳基正极材料的发展及其在锂空气电池中的应用前景做了展望。     

Applications of Nanomaterials in Microbial Fuel Cells: A Review

Microbial fuel cells (MFCs) are an environmentally friendly technology and a source of renewable energy. It is used to generate electrical energy from organic waste using bacteria, which is an effective technology in wastewater treatment. The anode and the cathode electrodes and proton exchange membranes (PEM) are important components affecting the performance and operation of MFC. Conventional materials used in the manufacture of electrodes and membranes are insufficient to improve the efficiency of MFC. The use of nanomaterials in the manufacture of the anode had a prominent effect in improving the performance in terms of increasing the surface area, increasing the transfer of electrons from the anode to the cathode, biocompatibility, and biofilm formation and improving the oxidation reactions of organic waste using bacteria. The use of nanomaterials in the manufacture of the cathode also showed the improvement of cathode reactions or oxygen reduction reactions (ORR). The PEM has a prominent role in separating the anode and the cathode in the MFC, transferring protons from the anode chamber to the cathode chamber while preventing the transfer of oxygen. Nanomaterials have been used in the manufacture of membrane components, which led to improving the chemical and physical properties of the membranes and increasing the transfer rates of protons, thus improving the performance and efficiency of MFC in generating electrical energy and improving wastewater treatment.     

A Critical Review on Hydrogen Based Fuel Cell Technology and Applications

The research in energy storage and conversion is playing a critical role in energy policy as the innovation and technological progress are essential for achieving the energy transition and climate neutrality goals. Hydrogen Fuel Cell technology is considered a strategic element in the pursuit of sustainable and clean energy solutions. This technology is increasingly gaining attention in recent years as a potential substitute to conventional non-renewable energy sources. Fuel cell technology can be employed for domestic/commercial use along with powering the transportation sector which currently employs the use of conventional battery systems. However, these systems pose severe limitations with respect to longer charging times and limited distance range. This review article aims at providing a comprehensive methodical overview of hydrogen-based fuel cell technology along with key concepts, present day scenarios, including overview of the market and industry trends, government policies and initiatives, along with major stakeholders involved in scaling up the technology for mass consumption. The outlook of fuel cells, including their capability to revolutionise the energy sector is discussed. The technological advancements and breakthroughs on the horizon along with the challenges and safety concerns related to the widespread acceptance of fuel cells are analysed.     

Fe-N-C 类催化剂在碱性燃料电池中的研究进展

随着阴离子交换膜的出现、发展和应用,碱性燃料电池的优势日趋明显,针对碱性燃料电池的研究也更广泛而深刻. 在碱性燃料电池中,除了其固有的对催化剂的高包容性和动力学优越性,阴离子交换膜让阴离子定向迁移,从而实现了很好的水相管理,降低了电池中“水涝”的几率,也提供了更广阔的燃料选择空间. 氧还原反应是碱性燃料电池中的重要部分,且其反应动力学相较于氢氧化反应缓慢. 因此,选择并研制合适的阴极氧还原反应催化剂,是提高碱性燃料电池性能和促进燃料电池规模化使用的关键. Fe-N-C类催化剂因其在碱性条件下接近甚至优于 Pt 基催化剂的性能,被视为最有潜力替代 Pt 的非贵金属催化剂. 本文从近 5 年来 Fe-N-C 类催化剂的合成方法、催化活性位点和氧还原反应机理以及在燃料电池中的应用三方面进行了综述.      

燃料电池非铂基氧还原电催化剂的最新研究进展

目前,燃料电池中广泛使用的Pt基阴极催化剂价格昂贵、资源缺乏,且易中毒,故急需开发廉价、耐用、高效和高耐醇的非铂基阴极氧还原催化剂. 本文阐述了国内外在非铂氧还原催化剂方面的研究,并着重介绍了作者课题组的最新研究进展. 主要集中在非贵金属（Fe）负载和杂原子（F）掺杂的非金属催化剂,力求原料廉价并可提高催化剂的催化活性、稳定性、抗毒化能力,实现较高的性价比. 同时通过理论计算解释了氟单掺杂和氮氟共掺杂高效性的根源,为设计高效催化剂提供了有力的理论支持.     

Pt基金属间化合物及其在质子交换膜燃料电池阴极氧还原反应中的应用

质子交换膜燃料电池是一种能够将燃料的化学能直接高效地和环境友好地转化为电能的绿色能源技术。质子交换膜燃料电池具有能量转化效率高、启动快速、零排放或者低排放等优点,被认为是后石油时代最为重要的能源替代技术之一。然而目前使用的电催化剂存在铂用量高和稳定性不足等问题。开发高性能低Pt催化剂对于降低质子交换膜燃料电池成本、促进质子交换膜燃料电池的大规模商业化应用具有十分重要的意义。Pt基金属间化合物是一类具有严格元素化学计量比和规整原子排列结构的合金化合物,其氧还原反应催化活性明显优于相应的Pt基无序合金及纯Pt催化剂,被认为是最具应用前景的低Pt催化剂之一。本文着重从催化机理、制备技术、组成调控、颗粒度调控、形貌调控和晶体结构等几个方面介绍了Pt基金属间化合物催化剂近来的研究进展,以及这类催化剂在质子交换膜燃料电池阴极氧还原反应中的应用研究情况,指出了这类催化剂目前尚存在的不足及挑战,并展望了未来的研究发展思路及方向。     

碱性燃料电池Co-N/C复合催化剂的电化学性能

碳黑经过酸处理后再加入醋酸钴经氨气900 ℃热处理后, 以其制备的气体扩散电极在6 mol•L^―1 KOH溶液中对氧还原反应(ORR)的电催化性能得到大大提高. XRD物相分析表明: 碳粉中加入醋酸钴经氨气热处理生成了氮化钴(Co_5.47N). 通过极化曲线和交流阻抗方法对制备的气体扩散电极在空气中的性能进行了研究. 室温时在－0.2 V (vs. Hg/HgO)电位下, 未经处理的碳电极对氧还原基本没有电流产生; 用酸处理后的碳电极在空气中的电流密度提高到57 mA•cm^―2; 而Co-N/C复合电极在同样条件下电流密度可达170 mA•cm^―2, 交流阻抗显示氮化物的生成减小了氧还原反应的阻抗, 增强了对氧还原反应的电催化作用.     

燃料电池Pt基核壳结构电催化剂的最新研究进展

综述了用于燃料电池的Pt基核壳结构电催化剂的制备方法和表征方法的最新研究进展.首先,详细介绍了核壳结构催化剂的制备方法,主要包括胶体法、电化学法和化学还原法等.其中胶体法的应用最为广泛,制备过程简单易控;电化学法和化学还原法在最近几年得到了迅速发展,并有望用于核壳结构电催化剂的批量化生产.其次,简单阐述了核壳结构电催化剂特用的表征方法.其中高角度环形暗场-扫描透射电子显微镜是近年来发展的一种新技术,它利用暗场强度与原子序数的比例关系可以有效地表征核壳电催化剂的特殊结构.最后,总结了存在的问题并展望了可能的发展方向.     

锌-空气电池双功能催化剂研究进展

锌-空气电池因其拥有理想的能量密度和功率密度,并有望在能源转化与储存领域的广泛应用,引起国内外研究者的高度关注. 其中,空气电极作为氧催化反应的核心区域,更是整个锌-空气电池研究的重点. 近年来,非贵金属双功能催化剂及其电极以其高活性、低成本以及种类丰富等特点取得了较多的研究成果. 本文综述了非贵金属氧化物催化剂、碳基催化剂、碳载过渡金属化合物复合材料以及自支撑电极在锌-空气电池中的反应机制和研究进展,提出了高效双功能催化剂的构建策略,并对双功能催化剂/电极的发展趋势进行了展望.     

非贵金属电催化析氧催化剂的最新进展

氢气具有环境友好、含量丰富、高能量密度等特点,是一种可以替代化石能源的绿色环保可再生能源. 电解水是制备氢气最有效途径之一. 但在电解水过程中,动力学过程非常缓慢,过电位较大的阳极析氧半反应严重限制了阴极析氢反应效率. 因此,研究高效、稳定和低成本的催化剂来降低析氧反应的过电位,从而提高析氢反应效率受到了广泛关注. 基于非贵金属催化剂本身特性及其在高浓度OH-条件下具有较高OER催化活性等原因,本文首先简要介绍碱性条件下析氧反应机理及其性能的评价方法,然后重点讨论非贵金属电催化析氧催化剂的最新研究进展. 最后对如何深入研究催化机理、设计高效、双功能及新型非贵金属电催化析氧催化剂进行了展望.     

质子交换膜燃料电池Pd修饰Pt/C催化剂的电催化性能

通过对Pt催化剂表面进行Pd修饰提高质子交换膜燃料电池阴极催化剂的氧还原反应(ORR)活性. 采用乙二醇还原法制备了不同比例的Pd修饰Pt/C催化剂. 透射电镜(TEM)和X射线衍射(XRD)测试结果表明, 制备的催化剂贵金属颗粒粒径主要分布在1.75～2.50 nm之间, 并均匀地分散在碳载体表面. 循环伏安方法(CV)研究表明Pd修饰Pt/C催化剂的电化学活性面积低于传统的Pt/C催化剂. 但通过旋转圆盘电极(RDE)测试研究发现, 制备的催化剂具有比传统Pt/C催化剂高的ORR活性.     

Recent Developments in Electrodeposition of Transition Metal Chalcogenides-Based Electrode Materials for Advance Supercapacitor Applications: A Review

High-performance supercapacitive electrode materials have received significant attention from researchers worldwide, thus aiming for comparable performance similar to the extensively used rechargeable batteries. For emerging energy storage technologies like flexible supercapacitors, transition metal chalcogenides (TMCs) have been in the spotlight due to their promising electrochemical features compared to other electrode materials. Among the synthesis techniques, electrodeposition-mediated preparation of thin films of TMCs offered an affordable binder-free approach for electrode fabrication that effectively improved the supercapacitor performance. Hence, this review mainly focussed on the electrodeposition-based syntheses of single/ multinary chalcogenides and their composites for supercapacitors applications. Further, the effects of different deposition parameters were discussed for boosting the supercapacitor performance. Finally, this review outlined the existing challenges and future perspectives in this research domain, which will assist the upcoming exploration in the energy storage field.     

Put the Sun in the Tank: Future Developments in Sustainable Energy Systems

The conversion of energy systems toward sustainable solutions has been progressing for several years. The effect on protecting the climate can now be estimated through new projections and is presented here for the European Union. The results are compared to the goals of the Paris Climate Agreement and show that additional, new and qualitative measures must be taken.     

Advancements in Perovskite-Based Cathode Materials for Solid Oxide Fuel Cells: A Comprehensive Review

The high-temperature solid oxide fuel cells (SOFCs) are the most efficient and green conversion technology for electricity generation from hydrogen-based fuel as compared to conventional thermal power plants. Many efforts have been made to reduce the high operating temperature (>800 °C) to intermediate/low operating temperature (400 °C<T<800 °C) in SOFCs in order to extend their life span, thermal compatibility, cost-effectiveness, and ease of fabrication. However, the major challenges in developing cathode materials for low/intermediate temperature SOFCs include structural stability, catalytic activity for oxygen adsorption and reduction, and tolerance against contaminants such as chromium, boron, and sulfur. This research aims to provide an updated review of the perovskite-based state-of-the-art cathode materials LaSrMnO₃ (LSM) and LaSrCOFeO₃ (LSCF), as well as the recent trending Ruddlesden-Popper phase (RP) and double perovskite-structured materials SOFCs technology. Our review highlights various strategies such as surface modification, codoping, infiltration/impregnation, and composites with fluorite phases to address the challenges related to LSM/LSCF-based electrode materials and improve their electrocatalytic activity. Moreover, this study also offers insight into the electrochemical performance of the double perovskite oxides and Ruddlesden-Popper phase materials as cathodes for SOFCs.     

过渡金属氧化物氧还原催化剂的研究进展

过渡金属氧化物（TMOs）是阴离子交换膜燃料电池最有前途的氧还原催化剂之一. 目前,TMOs的氧还原活性同铂基催化剂相比仍然有一定的差距,研究如何合成具有高催化活性的TMOs催化剂非常重要. 导电性和本征活性一直被认为是开发高性能TMOs催化剂的两个关键因素,本文着重总结与评述了近年来有关TMOs氧还原催化剂在导电性和本征活性方面的研究进展,尝试提出了未来提高TMOs氧还原催化活性的努力方向.     

SrNb0.1Co0.7Fe0.2O3−δ Perovskite as a Next‐Generation Electrocatalyst for Oxygen Evolution in Alkaline Solution

The perovskite SrNb_0.1Co_0.7Fe_0.2O_3?δ (SNCF) is a promising OER electrocatalyst for the oxygen evolution reaction (OER), with remarkable activity and stability in alkaline solutions. This catalyst exhibits a higher intrinsic OER activity, a smaller Tafel slope and better stability than the state‐of‐the‐art precious‐metal IrO₂ catalyst and the well‐known BSCF perovskite. The mass activity and stability are further improved by ball milling. Several factors including the optimized e_g orbital filling, good ionic and charge transfer abilities, as well as high OH^? adsorption and O₂ desorption capabilities possibly contribute to the excellent OER activity.     

Axial Ligand Coordination Tuning of the Electrocatalytic Activity of Iron Porphyrin Electrografted onto Carbon Nanotubes for the Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) is essential in many life processes and energy conversion systems. It is desirable to design transition metal molecular catalysts inspired by enzymatic oxygen activation/reduction processes as an alternative to noble-metal-Pt-based ORR electrocatalysts, especially in view point of fuel cell commercialization. We have fabricated bio-inspired molecular catalysts electrografted onto multiwalled carbon nanotubes (MWCNTs) in which 5,10,15,20-tetra(pentafluorophenyl) iron porphyrin (iron porphyrin FeF₂₀TPP) is coordinated with covalently electrografted axial ligands varying from thiophene to imidazole on the MWCNTs’ surface. The catalysts’ electrocatalytic activity varied with the axial coordination environment (i. e., S-thiophene, N-imidazole, and O-carboxylate); the imidazole-coordinated catalyst MWCNTs-Im-FeF₂₀TPP exhibited the highest ORR activity among the prepared catalysts. When MWCNT-Im-FeF₂₀TPP was loaded onto the cathode of a zinc−air battery, an open-cell voltage (OCV) of 1.35 V and a maximum power density (P_max) of 110 mW cm⁻² were achieved; this was higher than those of MWCNTs-Thi-FeF₂₀TPP (OCV=1.30 V, P_max=100 mW cm⁻²) and MWCNTs-Ox-FeF₂₀TPP (OCV=1.28 V, P_max=86 mW cm⁻²) and comparable with a commercial Pt/C catalyst (OCV=1.45 V, P_max=120 mW cm⁻²) under similar experimental conditions. This study provides a time-saving method to prepare covalently immobilized molecular electrocatalysts on carbon-based materials with structure–performance correlation that is also applicable to the design of other electrografted catalysts for energy conversion.     

Synthesis,Chemical–Physical Characterization,and Biomedical Applications of Functional Gold Nanoparticles: A Review

Relevant properties of gold nanoparticles, such as stability and biocompatibility, together with their peculiar optical and electronic behavior, make them excellent candidates for medical and biological applications. This review describes the different approaches to the synthesis, surface modification, and characterization of gold nanoparticles (AuNPs) related to increasing their stability and available features useful for employment as drug delivery systems or in hyperthermia and photothermal therapy. The synthetic methods reported span from the well-known Turkevich synthesis, reduction with NaBH₄ with or without citrate, seeding growth, ascorbic acid-based, green synthesis, and Brust–Schiffrin methods. Furthermore, the nanosized functionalization of the AuNP surface brought about the formation of self-assembled monolayers through the employment of polymer coatings as capping agents covalently bonded to the nanoparticles. The most common chemical–physical characterization techniques to determine the size, shape and surface coverage of AuNPs are described underlining the structure–activity correlation in the frame of their applications in the biomedical and biotechnology sectors.     

铂基燃料电池氧还原反应催化剂研究进展

质子交换膜燃料电池中,空气电极上进行的氧还原反应动力学过程迟缓,是贵金属铂催化剂的主要消耗反应,但铂储量有限、成本过高、稳定性差等缺点严重制约了质子交换膜燃料电池大规模商业化应用. 开发低载量、高催化活性、高稳定铂催化剂是降低燃料电池成本的重要途径之一. 本文以作者课题组近年工作为基础,综述了铂基催化剂的稳定性研究,以及以铂合金为代表的低铂氧还原反应催化剂的最新研究进展. 文章重点讨论了催化剂的结构设计与制备,并对未来氧还原催化剂的发展提出了展望