电催化析氧反应过渡金属硫化物催化剂研究进展

析氧反应（oxygen evolution reaction, OER）、析氢反应（hydrogen evolution reaction, HER）和氧还原反应（oxygen reduction reaction, ORR）为电解水、金属-空气电池等能源器件的半反应。其中,OER由于涉及4e^-转移和O-O键的形成而导致反应动力学迟缓和过电势高,因此,开发优异的OER电催化剂能够有效提高能量转换效率。到目前为止,过渡金属硫化物催化剂（transition metal sulfide catalysts, TMSs）被研究人员大量研究和报道,并且取得飞跃发展。介绍在不同电解质中的OER机制,并通过对近几年相关文献的综合归纳,探究TMSs催化剂的组成、导电性、质子传输、缺陷程度、界面化学等多种因素对OER的影响。综述目前过渡金属硫化物电催化剂在OER领域所面临的挑战和研究进展,希望为TMSs的研究者提供借鉴。     

煤基活性炭制备及其电催化应用研究进展

煤炭是世界上储量最为丰富的化石燃料之一,是制造多孔碳、纳米碳、碳质复合材料和石墨烯的主要原料。燃料电池是一种通过化学反应将化学燃料直接转化为电能的装置,它不受卡诺循环限制,具有高效率、高功率密度和环境友好等特点,有着巨大的应用前景。但其阴极氧还原反应(cathodic oxygen reduction reaction, ORR)动力学非常缓慢,需要在催化剂的作用下加速其反应。现有的催化剂主要是贵金属Pt,但Pt资源储量少、成本高、稳定性差,限制了燃料电池的商业化应用。近年来的研究表明,碳基材料是最有希望替代Pt的催化剂材料。基于此,对近年来煤基多孔碳的制备方法进行了综述,并在此基础上阐述了以煤基活性炭为基体的燃料电池用氧还原电催化剂的研究进展。     

基于3d过渡金属的氧电极材料研究进展

氧还原催化剂及缓慢的阴极氧还原动力学是制约低温燃料电池商业化的关键瓶颈因素之一.非贵金属氧还原催化剂是近年来低温燃料电池最受关注的研究热点之一.在简要介绍燃料电池及氧还原反应机理的基础上,详细地综述了近年来低温燃料电池用3d过渡金属基氧还原催化剂的主要研究进展,包括过渡金属大环化合物、过渡金属-氮/碳类化合物、过渡金属硫族化合物和过渡金属氧化物,总结了提高催化活性和稳定性、降低催化剂制备成本以及催化剂制备工艺等方面所取得的研究结果,并指出了各类催化剂目前尚待解决的问题和发展方向.     

Nitrogen-doped graphene nanosheets as high efficient catalysts for oxygen reduction reaction

It is of great significance in exploring alternative catalysts to platinum (Pt)-based materials for oxygen reduction reaction (ORR),because this reaction is invariably involved in various fuel cells and metal-air batteries.We herein reported the nitrogen doped graphene nanosheets (NGNSs) with pore volume of as high as 3.42 m 3 /g and investigated their potential application as ORR catalysts,it was demonstrated the NGNSs featured high activity,improved kinetics and excellent long-term stability for ORR.The NGNSs were successfully used as cathode catalysts of microbial fuel cells (MFCs) and performed even better than the commercial Pt/C (Pt 10%) catalysts at the maximum power output.     

氢燃料电池阴极氧还原反应电催化剂研究进展

氢燃料电池是一种将化学能直接转换为电能的能量转换装置,具有转换效率高、噪声低、无污染、原料多样且用途广泛等优点,但其阴极氧还原反应(oxygen reduction reaction,ORR)动力学缓慢,极大地限制了其大规模应用与发展．因此,研发高效、耐用兼具经济性的ORR电催化剂是当前研究热点之一．在众多科研工作者的努力下,关于ORR电催化剂的研究工作已取得了许多重要突破性进展．本综述系统介绍了ORR反应机制和目前3种主流类别的ORR电催化剂(贵金属、非贵金属、碳基)的研究进展,着重分析了不同催化剂体系的性能与优缺点,并探讨了高性能ORR电催化剂的合成策略及其未来的发展方向．      

Central electron-enriched NO-FeN4 sites as superior acidic oxygen reduction reaction electrocatalysts for proton exchange membrane fuel cells

Developing nobel-metal-free catalysts, especially for iron-nitrogen on carbon (FeNC) materials, has been an urgent demand for wide applications of proton exchange membrane fuel cells (PEMFCs). However, the inferior oxygen reduction reaction (ORR) activity of traditional iron-nitrogen sites in acidic conditions seriously impedes the further improvement of their performance. Herein, we synthesized FeN₄ with NO (nitric oxide) group axial modification (denoted as NO-FeN₄) on a large scale through a confined small molecule synthesis strategy. Benefitting from the strong electron-withdrawing effect of the NO group, the central electron-rich FeN₄ site exhibits ultrahigh ORR activity with a three times higher mass activity (1.1 A·g?1 at 0.85 V) compared to the traditional FeN₄ sample, as well as full four-electron reaction selectivity. Moreover, the PEMFC assembled with the as-prepared electrocatalyst also exhibits a greatly enhanced peak power density (>725 mW·cm?2). This work provides a new approach to rationally design advanced M-N_x nonnoble electrocatalysts for the ORR.     

热解聚苯胺合成氮掺杂MnCo2O4-C氧还原催化剂

通过热解聚苯胺涂层的Mn Co2O4颗粒制备出Mn Co2O4/N-C材料,即一种新型的碱性聚合物电解质膜燃料电池(APEFC)阴极非贵金属催化剂。在不同温度下热处理得到了一系列的Mn Co2O4/N-C催化剂,对其进行XRD、Raman、XPS表征和LSV电化学测试,结果表明:热处理温度为900℃,Mn Co2O4质量分数为15%时,Mn Co2O4/N-C催化剂具有最佳的催化活性,氧还原反应起始电位为0.90 V;该催化剂中石墨型的碳和氮含量最高,这是其具有较高的氧还原催化活性一个重要因素。     

Nickel-introduced structurally ordered PtCuNi/C as high performance electrocatalyst for oxygen reduction reaction

Designing highly active and durable oxygen reduction reaction (ORR) electrocatalysts is essential for developing efficient proton-exchange membrane fuel cells (PEMFCs). In this work, ordered PtCuNi/C nanoparticles (NPs) were synthesized using an impregnation reduction method. This study shows that the incorporation of Ni in ordered PtCu/C can effectively adjust the electronic structure of Pt, thereby optimizing oxygen binding energy for the ORR. The obtained intermetallic ordered PtCuNi/C NPs significantly improved ORR activity and durability compared to ordered PtCu/C. Specifically, PtCu_0·5Ni_0·5/C-700 shows a mass activity of 1.29 ​A ​mg _Pt⁻¹ ​at 0.9 ​V vs. reversible hydrogen electrode (RHE), which is about 9.2 times higher than that of commercial Pt/C. PtCu_0.5Ni_0.5/C-700 is also shown to be competent cathode catalyst for a single-cell system exhibiting high power density (461 ​mW ​cm⁻²). This work demonstrates that ordered PtCu_0·5Ni_0·5/C-700 can be used as a highly active and durable ORR catalyst in PEMFCs.     

Low-dimensional catalysts for oxygen reduction reaction

Developing highly efficient electrocatalysts to facilitate the sluggish cathodic oxygen reduction reaction (ORR) is a key challenge for high-performance fuel cells. Low-dimensional materials have attracted great attention recently because of their unique structure and properties. In this review, the application of zero-dimensional (0D), one‐dimensional (1D), and two‐dimensional (2D) materials in ORR are discussed and particular attention is given to the relationship between their structure and the ORR activity. Graphene-based materials, transition metal dichalcogenides, transition metal oxide, nanotubes, nanoribbons, nanowires, and single-atom ORR catalysts are introduced and classified by their geometric dimension.     

钴基氧还原电催化材料研究进展

氧还原反应(oxygen reduction reaction,ORR)是能量转换和储存系统的关键电极反应。目前,贵金属基材料,如铂和钯,是ORR最有效的催化剂,但其地球储量稀少、价格昂贵,且抗甲醇和CO性能差。因此,开发新型、低成本、高性能的氧还原电催化剂对能源转化和储存具有重要意义。综述了近年来非贵金属钴(Co)基氧还原电催化材料的研究进展及其性能调控策略,分为Co合金、Co-N-C、Co纳米粒子、Co基氧化物、Co基磷化物和Co基硫化物等多种形式,并对未来开发低成本、高性能的氧还原催化剂进行了展望。     

ZIF-derived Co–N–C ORR catalyst with high performance in proton exchange membrane fuel cells

Metal and nitrogen-doped carbon (M-N-C) materials have been considered as the most promising non-precious metal oxygen reduction (ORR) catalysts to replace expensive Pt catalysts. Due to high Fenton catalytic activity of Fe element and the resulting instability, Co-based N–C (Co–N–C) catalysts without Fenton catalytic activity should be a worthier ORR catalyst being explored. Although the high ORR activity of Co–N–C catalyst has been demonstrated in aqueous half-cell tests, their performance under PEMFC working condition is still far away from that of state-of-the-art Fe–N–C catalysts. In this study, a high-performance Co–N–C catalyst was synthesized by one-step pyrolyzing Co-doped ZIF-8 (zeolitic imidazolate framework-8) particles in-situ grown on the high-surface-area KJ600 carbon black with high electronic conductivity. The resulting Co–N–C catalyst exhibited high intrinsic ORR activity, fast mass transfer rate and high electronic conductivity, and thus yielded a remarkable peak power density of 0.92 W cm^-2 in H₂–O₂ PEMFC, which is comparable to state-of-the-art Fe–N–C catalyst. This strategy is helpful to synthesize highly active M-N-C ORR catalysts with improved mass transfer and electric conductivity.     

氮掺杂聚苯胺-碳氧还原催化剂的制备与表征

采用软模版法合成聚苯胺前躯体，通过改变过渡金属制备出PANI-FeCo-C、PANI-Fe-C、PANI-Co-C和PANI-C质子交换膜燃料电池(PEMFC)阴极非贵金属催化剂。电化学测试结果表明：4种催化剂中，PANI-Fe-C的催化活性最好，其氧还原反应起始电位达到0.87V。通过X射线衍射光谱（XRD）、拉曼（Raman）光谱、透射电子显微镜（TEM）、能量色散X射线光谱（EDS）和X射线光电子能谱（XPS）测试可知，PANI-Fe-C催化剂中含有较多晶格畸变的碳和石墨型的氮，这些特性是其具有优越氧还原催化性能的重要原因。     

Surface modifications of Pt-based atomically ordered nanoparticles to improve catalytic performances for oxygen reduction reaction

Bimetallic platinum-cobalt (Pt–Co) nanostructure catalysts represent superior catalytic performances for oxygen reduction reaction (ORR). In a variety of Pt–Co catalyst structures, atomically ordered structure catalysts show excellent catalytic performances in the ORR. In this work, for promoting their catalytic performances, atomically ordered PtCo nanoparticles (PtCo/C) with carbon supported were successfully prepared by an improved impregnation method and annealing. Then, the ordered PtCo/C catalysts have been significantly improved by doped with ultralow amount of Au and Cr transition metal. The physical and electrochemical test results demonstrate the Cr–PtCo/C and Au–PtCo/C catalysts have superior catalytic performances including mass activity and stability compared to commercialized Johnson Matthey (JM) Pt/C, which was the result of the modified electronic properties of Pt surface and atomically ordered structure. The presence of Au and Cr enhances the stability of PtCo/C catalysts. This work represents a simple way to promote the catalytic performances of the atomically ordered catalysts.     

Multiple metallic dopants in nickel nanoparticles for electrocatalytic oxygen evolution

Developing efficient oxygen evolution reaction(OER) electrocatalysts is of great importance for sustainable energy conversion and storage. Ni-based catalysts have shown great potential as OER electrocatalysts, but their performance still needs to be improved. Herein, we report the multiple metal doped nickel nanoparticles synthesized via a simple oil phase strategy as efficient OER catalysts. The FeMnMoV–Ni exhibits superior OER performance with an overpotential of 220 mV at 10 mA cm^-2     

氮掺杂还原氧化石墨包覆金属钴复合材料的制备及其氧还原性能的研究

采用搅拌反应法制备了ZnCo（ZIF）与氧化石墨（graphite oxide,GO）的复合材料,热处理得到Co@N-doped rGO催化剂。通过X射线衍射（X-ray diffraction,XRD）和扫描电子显微镜（scanning electron microscopy,SEM）对催化剂进行结构表征,通过X射线光电子能谱（X-ray photoelectron spectroscopy,XPS）对催化剂进行表面元素分析,分别考察了金属（Zn和Co）加入量和热处理温度对催化剂氧气还原反应（oxygen reduction reaction,ORR）催化性能的影响,结果表明：所制备的催化剂整体呈层状分布,表面附着金属小颗粒团簇;随着金属加入量的增加,催化剂的ORR催化性能先增强后减弱;随着热处理温度的升高,催化剂的ORR催化性能先增强后减弱。所制备的S-2-850催化剂具有最好的ORR催化性能,在0.1 mol/L KOH电解液中,其起始电位和半波电位分别为0.871 V和0.804 V,在相同测试条件下活性稳定性优于20% Pt/C。     

Pyrolysis of Iron(III) porphyrin coated Pt/C toward oxygen reduction reaction in acidic medium

Design and synthesis of highly active and durable electrocatalysts toward oxygen reduction reaction (ORR) is of particular importance for proton exchange membrane fuel cells (PEMFCs), yet remains a grand challenge. Herein, we report the deposition of iron (III) porphyrin (FeP) on house-made Pt/C by rotary evaporation of the mixture of FeP and house-made Pt/C dispersed in chloroform, followed by pyrolysis at 650 °C in argon atmosphere. This approach led to the synthesis of new non-precious metal electrocatalyst (NPME)-Pt/C composites (Pt/C–FeP) with an average nanoparticle diameter of 3.1 ± 1.5 nm without aggregation. According to X-ray photoelectron spectroscopy (XPS), the binding energy of Pt 4f_7/2 became larger due to the presence of pyrolyzed FeP. In addition, the electrochemically active surface area (ECSA) of Pt/C–FeP-650 is 65 m²/g less than that of house-made Pt/C (80.2 m²/g). This implies that the pyrolyzed FeP may have partially covered the surface of Pt nanoparticles and thus lowering the ECSA. Interestingly, the mass activity (MA) of Pt/C–FeP turns out to be 349.0 mA/mg_Pt @0.9 V vs. RHE, which is 2.6 times and 1.5 times of house-made Pt/C and commercial Pt/C, respectively. It is speculated that the electronic interaction and possible synergy between Pt and pyrolyzed FeP as NPME might have contributed to the ORR activity improvement despite of partial loss of ECSA. During accelerated durability tests (ADTs), the MA of Pt/C–FeP-650 degrades 64.3% inferior to commercial Pt/C (52.2%). The main reason likely arises from the degradation of pyrolyzed FeP, which is a bottleneck problem confronting NPMEs.     

Large specific surface area S-doped Fe–N–C electrocatalysts derived from Metal–Organic frameworks for oxygen reduction reaction

It is highly desired but challenging to develop platinum group metal-free electrocatalysts for oxygen reduction reaction (ORR), which can promote the commercialization of fuel cell technology. To achieve this target, we report a one-step doping method to prepare S-doped Fe–N–C catalysts using zeolite imidazole framework (ZIF-8) and iron (III) thiocyanate (Fe(SCN)₃) as precursor. Different from conventional doping approach, i.e. physical mixing, Fe(SCN)₃ is in-situ added during ZIF-8 formation which would encapsulate Fe(SCN)₃ molecules inside ZIF-8 to avoid structure destruction and create potential replacement of Zn ions by Fe ions to form uniform Fe–N₄ complexes. As a result, the prepared S-doped Fe–N–C catalysts own large specific surface areas with a maximum value of 1326 ​m² ​g⁻¹ and a dual-scale porous structure that benefits mass transport. Significantly, the composition-optimized catalyst exhibits superior ORR activity in both 0.1 ​M HClO₄ electrolyte and 0.1 ​M KOH electrolyte, in which the half-wave potential reaches 0.81 ​V and 0.92 ​V (vs. RHE), respectively. Remarkable stability is also attained, which loses 2 ​mV only after 10000 potential cycles in O₂-saturated 0.1 ​M HClO₄ and remains almost constant in O₂-saturated 0.1 ​M KOH, surpassing commercial Pt/C catalyst in both acidic and alkaline medium.     

NiCo-MOF-74的制备及其电催化氧气析出性能

采用简单的一步水热法制备了不同Ni、Co物质的量比的双金属NiCo-MOF-74催化剂,利用X射线衍射（XRD）、扫描电子显微镜（SEM）、X射线光电子能谱（XPS）和N₂吸/脱附法（BET）对催化剂进行了结构表征,并且在1 mol/L KOH电解液中通过线性伏安法评价了催化剂的氧气析出反应（OER）催化性能。结果表明：所制备的催化剂中含有C、O、Co、Ni 4种元素,并且具有棒状多面体结构和较高的结晶度;当Ni含量较低时,催化剂具有较好的OER催化活性;当Ni的摩尔分数超过10%时,催化剂的OER催化性能随着Ni含量的增加而下降。通过调节原料中Ni、Co的物质的量比,制得的Ni0.5Co9.5-MOF-74样品具有最好的OER催化性能,其在电流密度为10 mA/cm²时的过电压仅为352 mV,在相同测试条件下稳定性优于RuO₂。     

Surface-confined Pt-based catalysts for strengthening oxygen reduction performance

Developing highly efficient catalysts for the oxygen reduction reaction (ORR) is a key to the fabrication of commercially viable fuel cell devices for future energy applications. Considerable progress has been made to reduce Pt usage and improve performance of the Pt catalysts by modulating exposed facets of Pt nanocrystals and combining Pt with other metals to generate bimetallic nanocrystals with structures in the form of alloys, core-shells, branches or anisotropies. Apart from the above methods, confining Pt-based nanoparticles (NPs) surfaces with elaborately selected layers such as polymers, silicon or carbons can also lead to an optimized Pt electronic structure, which is beneficial to ORR process. In this minireview, we summarize the recent advancements in the area of surface-confined Pt-based electrocatalysts for ORR with emphasis on introducing the design strategies and synthesis methodologies. The integration of these catalysts into ORR operations and the resulting performance as well as the strengthening mechanisms is also discussed. Meanwhile, the insights into the research directions are proposed in order to shed light on the future development of surface-confined Pt-based ORR catalysts.     

A novel bimetallic RuFe nanocluster to enable highly efficient oxygen reduction in zinc-air batteries

Zinc-air batteries (ZABs) have the advantages of high energy density and safety but their large-scale application is hindered by sluggish kinetics of four-electron aqueous O₂ redox reactions. Widely used Ruthenium (Ru)-based catalysts possess intrinsic oxygen evolution catalytic activity but suffer from insufficient oxygen reduction reaction (ORR) performance. Herein, to optimize the ORR activity of Ru-based catalyst, an iron (Fe)-coordinated, bimetallic RuFe cluster is constructed and homogeneously dispersed within nitrogen (N)-doped carbon layers (denoted as RuFe@NC). Benefitting from the optimized ORR activity and more active site exposure, the RuFe@NC exhibits superior ORR activity with a half wave potential (E_1/2) of 0.88 ?V higher than that of Pt/C (0.82 ?V). Accordingly, the RuFe@NC-based ZAB outperforms the Pt/C ?+ ?IrO₂-based device, presenting a reduced polarization of 0.7 ?V and an enhanced cycling lifetime of 50 ?h at 10 ?mA ?cm^?2. Moreover, the optimized structural design ultralow Ru loading (0.013 mg_Ru cm^?2) overcomes the cost barriers and demonstrates its high practicality. This bimetallic RuFe nanocluster opens a new way for future design of more efficient and stable catalytic systems.