石墨烯衍生物负载的纳米催化剂用于氧还原反应

综述了用于燃料电池中氧还原反应(ORR)的石墨烯衍生物负载的各种纳米催化剂的最新进展。介绍了用于表征石墨烯基电催化剂的常规电化学技术以及石墨烯基电催化剂最新的研究进展。负载于还原氧化石墨烯(RGO)上的Pt催化剂的电化学活性和稳定性均得到显著提高。其它贵金属催化剂,如Pd, Au和Ag也表现出较高的催化活性。当以RGO或少层石墨烯为载体时, Pd催化剂的稳定性提高。讨论了氧化石墨烯负载Au或Ag催化剂的合成方法。另外,以N4螯合络合物形式存在的非贵过渡金属可降低氧的电化学性能。 Fe和Co是可替代的廉价ORR催化剂。在大多数情况下,这些催化剂稳定性和耐受性的问题均可得到解决,但其整体性能还很难超越Pt/C催化剂。     

氧还原和析氧反应的双功能电催化剂--氮磷共掺碳负载四氧化三钴

金属-空气电池具备诸多优势,譬如绿色环保、能量转化率高、启动快速、能量密度高、使用寿命和干态存储时间长等.与燃料电池相比,金属-空气电池结构简单,放电电压平稳,成本低,但依然存在一些制约发展的问题,如阴极催化剂.阴极催化剂在金属-空气电池中发挥催化氧还原反应(oxygen reduction reaction, ORR)和析氧反应(oxygen evolution reac-tion, OER)的关键作用.铂及其合金常用作 ORR的单功能催化剂,而钌和铱等是目前 OER催化效率最高的,但 ORR活性很低,因此需要开发出一种廉价而又具备双功能催化作用的催化剂.单异原子掺杂的碳基催化剂的研究集中在 ORR催化性能上,而多异原子共掺碳最近有研究表明具有双催化氧的性质,如氮磷共掺碳.在这些氮磷共掺的碳架中,氮磷共掺物起着 OER催化作用,掺氮物为 ORR催化的活性位点,而掺磷物起着强化作用.异原子掺杂负载的钴基催化剂(如掺氮还原氧化石墨烯载 Co3O4)是近年来双功能催化剂研究的另一个热点.钴基催化剂有着催化 ORR和 OER的多价价态,然而其本身导电性能差,这一缺陷可通过杂化石墨化碳来弥补,石墨化碳有着优良的导电性能.据我们所知,目前仍没有关于氮磷共掺碳负载的 Co3O4双催化氧的研究.我们合成了氮磷共掺碳(NPC)负载的 Co3O4(Co3O4/NPC),并首次探索了其氧还原和析氧性能. Co3O4/NPC合成分两步进行.首先通过三聚氰胺与植酸之间的酯化或缩聚覆盖在导电炭黑颗粒表面,在保护气氛下焙烧得到 NPC,然后经溶剂热反应以及空气中氧化合成 Co3O4/NPC.催化剂的性能综合考虑了催化活性和稳定性两方面.采用线性扫描伏安法评估了 OER和 ORR的催化活性.对于 OER, Co3O4/NPC的起始电势是0.54 V (以饱和甘汞电极为参比电极),在0.80 V时电流密度达到21.95 mA/cm2,均优于 Co3O4/C和 NPC. Co3O4/NPC的高效 OER催化可归因于氮磷共掺物与 Co3O4之间的协同作用.对于 ORR, Co3O4/NPC的催化效率与商用 Pt/C相近,它们的扩散极限电流密度分别为–4.49和–4.76 mA/cm2(E =–0.80 V).在 ORR过程中, Co3O4起到主要的催化作用.采用计时电流(电流-时间)法评估了催化剂的稳定性.经6 h测定,对于 OER, Co3O4/NPC剩46%电流;而对于 ORR,剩95%电流.整体而言, Co3O4/NPC在 OER和 ORR中都表现出高的催化效率以及良好的稳定性.     

金属锑基硫族团簇的合成、结构及电催化氧还原反应性能

为探索金属硫族团簇材料的多样性结构及其光电应用, 利用溶剂热法, 以含孤对电子的金属 Sb(Ⅲ)与硫元素采用不对称的配位几何方式结合, 合成了 Sb 基硫族团簇化合物[Sb₄S₅(S₃)]·C₅H₁₁N(1)和(C₅H₁₂N)₂[In₂Sb₂S₇] (2)。2 种化合物分别由{SbS₃}或{InS₄}配位单元之间以顶点共享的方式组合而成。电催化氧还原反应(ORR)研究表明, 化合物2 的极限电流密度和半波电位均高于化合物1, 表明其 ORR性能更好。Koutecky-Levich图分析表明, 由混合金属构筑而成的层状化合物2 的 ORR催化过程以四电子路径为主。     

金属锑基硫族团簇的合成、结构及电催化氧还原反应性能

为探索金属硫族团簇材料的多样性结构及其光电应用,利用溶剂热法,以含孤对电子的金属Sb(Ⅲ)与硫元素采用不对称的配位几何方式结合,合成了Sb基硫族团簇化合物 [Sb₄S₅(S₃)]·C₅H₁₁N (1)和(C₅H₁₂N)₂[In₂Sb₂S₇] (2)。2种化合物分别由{SbS₃}或{InS₄}配位单元之间以顶点共享的方式组合而成。电催化氧还原反应(ORR)研究表明,化合物2的极限电流密度和半波电位均高于化合物1,表明其ORR性能更好。Koutecky-Levich图分析表明,由混合金属构筑而成的层状化合物2的ORR催化过程以四电子路径为主。     

基于内嵌钴/氮掺杂多孔碳三维石墨烯笼的抗团聚高效氧还原电催化剂

氧还原反应是决定燃料电池、金属-空气电池等多种新型清洁能源存储与转化技术之性能与应用的关键反应. 铂及其合金是目前催化活性最好的氧还原反应催化剂,但其高昂的成本限制了规模化应用. 在小尺寸效应作用下,微纳米结构催化剂颗粒在电极制备与电化学反应过程中的团聚限制了催化剂本征催化活性的充分发挥. 本文基于喷雾热解技术,发展了一种基于内嵌钴/氮掺杂多孔碳三维石墨烯笼的高活性、抗团聚非贵金属氧还原反应催化剂. 此结构中,金属有机骨架化合物ZIF-67衍生的钴/氮掺杂多孔碳纳米结构是催化氧还原反应的活性中心,包覆其外的三维石墨烯笼不仅可在钴/氮掺杂碳纳米结构之间构建连续的三维载流子传导网络,且可高效抑制其在催化剂制备与电化学反应过程中的团聚与活性损失. 在碱性电解液中,此类非贵金属催化剂表现出可与铂基催化剂媲美的氧还原反应活性和优异的稳定性.     

金属硫族非超四面体In-Sn-S团簇的合成、结构及电催化氧还原反应性能

开发由金属In和Sn参与构筑的金属硫族非超四面体(non-Tn)团簇材料,对于实现该类材料的结构多样性及丰富其光电应用十分重要。利用溶剂热法合成了一系列新的 non-Tn 团簇化合物(C₇H₁₃N₂)[InS₂] (1)、(C₇H₁₃N₂)₄[In₂S₁₁Sn₃] (2)和(C₇H₁₃N₂)₃[In₃S₁₂Sn₃] (3),其中C₇H₁₃N₂=质子化1,5-二氮杂双环[4.3.0]壬-5-烯。3种化合物由{SnS₄}、{InS₄}或{InS₅}三个配位单元之间以边共享或顶点共享的方式组合而成。电催化氧还原反应(ORR)研究表明,化合物1~3的还原峰电位分别为0.60、0.64和0.65 V,含有Sn(Ⅳ)的化合物2和3表现出更好的催化性能。不仅如此,Koutecky-Levich图分析表明,化合物中In和Sn的组成比例对其ORR催化路径有明显的调节作用。     

用于氧还原反应的双原子钴-铁催化剂（英文）

金属-空气电池因其高效率和便携性受到广泛关注.然而,氧还原反应(ORR)的高能垒和缓慢的动力学导致其输出功率低.尽管贵金属铂基材料具有较高的ORR活性,但其在工业上的大规模应用受到高成本的制约.因此,迫切需要以储量丰富的非贵金属为原料,开发具有低成本、高性能和耐用性的催化剂.近年来,单原子过渡金属与氮共掺杂碳材料(M-N-C)成为替代贵金属催化剂的理想材料.理论模拟和实验结果均表明,单原子Fe/Co-N-C催化剂具有良好的ORR活性,其中FeN₄和CoN₄构型被认为是主要活性位点.此外,含有相邻金属位点的双金属单原子催化剂具有加速ORR动力学的巨大潜力.通过对ORR中间体的桥式-顺式吸附,双金属位点可以促进O-O键的裂解,从而提高催化活性.除固有活性外,双金属位点可减少ORR过程中含氧中间体对M-N键的攻击,提高M-N-C对ORR的耐久性和工业应用潜力.因此,近年来,研究者开始探索双金属单原子催化剂的合成和电催化性能,发现Fe-Co, Fe-Mn, Fe-Cu, Co-Zn和Co-Pt双位点可以有效催化ORR.为进一步提高ORR活性,需要合理...     

碳点衍生的碳纳米花负载钴单原子和纳米颗粒用于高效的氧还原反应（英文）

锌空气电池(ZABs)具有高能量密度(1086 m Wh gZn^–1)、价低、易回收等优势,引起了学者们的广泛关注.空气电极发生的氧还原反应(ORR)/氧析出反应(OER)是控制整个ZABs效率的关键.因此,设计和开发高效的ORR电催化剂对于ZABs商业化至关重要.目前, Pt基电催化剂仍是最有效的ORR电催化剂,但Pt资源稀缺,价格高昂,Pt基电催化剂稳定性差等缺点阻碍了其商业化.因此,研究高活性和高稳定性的ORR非贵金属电催化剂十分重要.碳点(CDs)作为一种新型的零维高分子碳材料,具有低毒、高导电性等优势,被广泛用于碳基材料的前驱体.CDs具有sp²杂化晶核、丰富的边缘位点和大量的官能团(如-NH₂,-COOH和-OH),这些表面官能团为过渡金属原子提供了很强的锚定位点,可用于构筑各种碳负载过渡金属催化剂.本文设计合成了一种新型的碳基ORR电催化剂,其由CDs衍生的三维碳纳米花(CNF)负载Co单原子(SAs)和纳米颗粒(NPs)构成.利用CDs在二次水热过程中形成了3.66 nm的超薄纳米膜并构筑成3D的多孔CN...     

Functional Electrospun Nanocomposites for Efficient Oxygen Reduction Reaction

Electrospinning with a simple and controllable process has extremely received considerable concerns by virtue of the fabrication and development of nanofibers. Moreover, nanofibers are playing an increasing impact on energy conversion and storage devices, especially for fuel cells based on oxygen reduction reaction(ORR), in view of the rich porosity, large surface area, excellent mass transportation and simply tunable composition, as well as good mechanical strength. In this review, we mainly introduce the primary principle of electrospinning technique, electrochemical reaction mechanism of ORR and synthetic strategies, and summarize the recent advances of unique non-noble-metal nanofibers on the basis of metal-organic framework(MOF) derivatives, single-atom catalysts(SACs) and transition metal oxides. More importantly, we emphasize on the influences of the components, morphology and architecture of advanced electrospun catalysts on their correspon-ding electrochemical performances towards ORR. Finally, the remaining puzzles and perspectives for further development of the electrospinning nanofibers involving electrocatalysis are presented. It is envisioned that this review would offer an important direction in designing novel electrocatalysts based on electrospinning nanofibrous structures and developing their potential.     

N,P-co-Doped Graphdiyne as Efficient Metal-free Catalysts for Oxygen Reduction Reaction

The carbon-based metal-free catalyst is one of the ideal alternatives to Pt as electrocatalysts for oxygen reduction reaction,which can reduce the cost of fuel cells and zinc-air batteries.Here,graphdiyne(GDY),a carbon material with uneven charge distribution,was used as substrate.By doping nitrogen and phosphorus,a N-P-GDY catalyst was prepared,which further regulated the electron structure of GDY.The sheet-like morphology of GDY was preserved in N-P-GDY.The N and P were distributed uniformly in the catalyst,whereas defects and active sites were created by doping N and P,as demonstrated by the element mapping images and Raman spectra.X-Ray photoelectron spectroscopy results indicated N and P existed in many forms in N-P-GDY.The N-P-GDY exhibited higher activity for ORR than only N or P doped GDY,due to the synergistic effect of N and P in N-P-GDY.Moreover,the activity of N-P-GDY changed little after a long time cyclic voltammetry test or injecting methanol in the electrolyte.Besides,the four electrons transfer reaction to produce water was the main process for ORR on N-P-GDY catalysts.     

Construction of Co,N-Coordinated Carbon Dots for Efficient Oxygen Reduction Reaction

For the sake of the oxygen reduction reaction (ORR) catalytic performance, carbon dots (CDs) doped with metal atoms have accelerated their local electron flow for the past few years. However, the influence of CDs doped with metal atoms on binding sites and formation mechanisms is still uncertain. Herein, Co,N-doped CDs were facilely prepared by the low-temperature polymerization–solvent extraction strategy from EDTA-Co. The influence of Co doping on the catalytic performance of Co-CDs was explored, mainly in the following aspects: first, the pyridinic N atom content of Co-CDs significantly increased from 4.2 to 11.27 at% compared with the CDs, which indicates that the Co element in the precursor is advantageous in forming more pyridinic-N-active sites for boosting the ORR performance. Second, Co-CDs are uniformly distributed on the surface of carbon black (CB) to form Co-CDs@CB by the facile hydrothermal route, which can expose more active sites than the aggregation status. Third, the highest graphite N content of Co-CDs@CB was found, by limiting the current density of the catalyst towards the ORR. Composite nanomaterials formed by Co and CB are also used as air electrodes to manufacture high-performance zinc–air batteries. The battery has good cycle stability and realizes stable charges and discharges under different current densities. The outstanding catalytic activity of Co-CDs@CB is attributed to the Co,N synergistic effect induced by Co doping, which pioneer a new metal doping mechanism for gaining high-performance electrocatalysts.     

负载酞菁铁的氮掺杂中空碳球的电催化氧还原性能（英文）

开发低成本、高性能的氧还原反应（ORR）催化剂是当前的研究热点.虽然酞菁铁（FePc）在几十年前就被证明能高效地电催化氧还原反应,但由于其电子传导性和稳定性较差,无法取代商用的Pt/C催化剂.氮掺杂碳材料不仅化学性质稳定、电子传导性好,还有一定的氧还原催化活性.本文首先制备了聚苯乙烯@聚多巴胺球前驱体,经过高温碳化后制得了氮掺杂中空碳球,进而负载酞菁铁后制备了负载酞菁铁的氮掺杂中空碳球复合材料（FePc-NHCS）.通过调整煅烧温度和酞菁铁的负载量,可进一步调控FePc-NHCS的多孔结构、石墨化程度、氮掺杂的种类与含量及酞菁铁的负载状态.优化后的FePc-NHCS在碱性电解质中显示出优异的ORR催化活性,其半波电位和稳定性均高于商用Pt/C催化剂.研究结果表明,掺杂与复合是增强单项催化组分活性的有效途径.此外,通过调控催化剂的结构和组分也能有效地优化催化剂的氧化还原性能.     

Amorphous Fe Nanoclusters Embedded inside Balloon-Like N-Doped Hollow Carbon for Efficient Electrocatalytic Oxygen Reduction

Rational designs of electrocatalytic active sites and architectures are of great importance to develop cost-efficient non-noble metal electrocatalysts towards efficient oxygen reduction reaction (ORR) for high-performance energy conversion and storage devices. In this work, active amorphous Fe-based nanoclusters (Fe NC) are elaborately embedded at the inner surface of balloon-like N-doped hollow carbon (Fe NC/C_h sphere) as an efficient ORR electrocatalyst with an ultrathin wall of about 10 nm. When evaluated for electrochemical performance, Fe NC/C_h sphere exhibits decent ORR activity with a diffusion-limited current density of ~5.0 mA/cm² and a half-wave potential of ~0.81 V in alkaline solution, which is comparable with commercial Pt/C and superior to Fe nanoparticles supported on carbon sheet (Fe NP/C sheet) counterpart. The electrochemical analyses combined with electronic structure characterizations reveal that robust Fe-N interactions in amorphous Fe nanoclusters are helpful for the adsorption of surface oxygen-relative species, and the strong support effect of N-doped hollow carbon is benefitial for accelerating the interfacial electron transfer, which jointly contributes to improve ORR kinetics for Fe NC/C_h sphere.     

氮掺杂石墨烯的制备及氧还原电催化性能

采用两步热解法, 用尿素掺杂氧化石墨烯(GO)得到N掺杂的还原氧化石墨烯(N-RGO), 通过控制反应温度, 制备了具有不同电催化活性的N掺杂的还原氧化石墨烯. 透射电子显微镜(TEM)和扫描电子显微镜(SEM)结果显示, 制得的氮掺杂石墨烯(nG)表面褶皱和重叠增加. X射线光电子能谱(XPS)证明, 氮元素以吡啶N、 吡咯N和石墨化的N 3种形式掺杂在石墨烯中, 最高摩尔分数为6.6%. 通过循环伏安(CV)和旋转圆盘电极(RDE)测试了nG的电化学性能, 结果表明, 在酸性电解质中对氧还原(ORR)有较高的催化活性, 起始电位在0.1 V左右, 电催化还原氧气时主要为四电子反应, 且相对商用的Pt/C催化剂有更好的电化学稳定性, 其中第一步热解温度为200℃制得的nG催化性能最好.     

A Layer-Structured Metal-Organic Framework-Derived Mesoporous Carbon for Efficient Oxygen Reduction Reaction

Developing highly active and durable electrocatalysts for the oxygen reduction reaction (ORR) is crucial to large-scale commercialization of fuel cells and metal-air batteries. Here we report a facile approach for the synthesis of nitrogen and oxygen dual-doped mesoporous layer-structured carbon electrocatalyst embedded with graphitic carbon coated cobalt nanoparticles by direct pyrolysis of a layer-structured metal-organic framework. The electrocatalyst prepared at 800℃ exhibits comparable ORR performance to Pt/C catalysts but possesses superior stability to Pt/C catalysts. This synthetic approach provides new prospects in developing sustainable carbon-based electrocatalysts for electrochemical energy conversion devices.     

Single-atom Fe Embedded Co3S4 for Efficient Electrocatalytic Oxygen Evolution Reaction

Constructing atomically dispersed active sites with densely exposed and dispersed double metal-S_x catalytic sites for favorable OER catalytic activity remains rare and challenging. Herein, we design and construct a Fe₁S_x@Co₃S₄ electrocatalyst with Fe single atoms epitaxially confined in Co₃S₄ nanosheets for catalyzing the sluggish alkaline oxygen evolution reaction(OER). Consequently, in ultralow concentration alkaline solutions(0.1 mol/L KOH), such a catalyst is highly active and robust for OER with low overpotentials of 300 and 333 mV at current densities of 10 and 30 mA/cm², respectively, accompanying long-term stability without significant degradation even for 350 h. In addition, Fe₁S_x@Co₃S₄ shows a turnover frequency(TOF) value of 0.18 s⁻¹, nearly three times that of Co₃S₄(0.07 s⁻¹), suggesting the higher atomic utilization of Fe single atoms. Mössbauer and in-situ Raman spectra confirm that the OER activity of Fe₁S_x@Co₃S₄ origins from a thin catalytic layer of Co(Fe)OOH that interacts with trace-level Fe species in the electrolyte, creating dynamically stable active sites. Combined with experimental characterizations, it suggests that the most active S-coordinated dual-metal site configurations are 2S-bridged (Fe-Co)S₄, in which Co-S and Fe-S moieties are shared with two S atoms, which can strongly regulate the adsorption energy of reaction intermediates, accelerating the OER reaction kinetics.     

Graphene Supported Platinum Nanoparticles as Catalyst for Oxygen Reduction Reaction

Graphene supported Pt nanoparticles were fabricated via electrochemical reduction method and the application of them in oxygen reduction reaction was also investigated. The results of field emission scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS) and Raman spectroscopy reveal that the interaction between Pt nanoparticles and graphene sheets can prevent graphene from agglomeration and improve the electronic conductivity of the composite. And the graphene supported Pt nanoparticles exhibit excellent electrocatalytic activity toward oxygen reduction reaction.     

Covalent Organic Frameworks Based Single-site Electrocatalysts for Oxygen Reduction Reaction

Single site catalysts(SSCs) are a new type of heterogeneous catalysts formed by isolated metal atoms supported on kinds of substrates. SSCs have shown great potential for energy conversion and storage in recent years, especially for oxygen reduction reactions(ORR). Typically, SSCs are confined on the substrate by strong chemical interactions, such as coordination bonds. Therefore, the surface chemical environment and porous properties of the supports are crucial to the performance of SSCs. In recent years, COFs have become excellent candidates for preparing SSCs as they can precisely assemble monomers into highly ordered crystalline porous materials with a fine structure and definite components. In this review, we not only summarize the characteristics and advantages of COFs based SSCs, but also highlight the applications of COFs constructed from different single active sites for ORR in recent years. Finally, challenges in practical application, feasible strategies and perspectives are proposed for the of COFs based SSCs.