A Cost‐Effective 3D Hydrogen Evolution Cathode with High Catalytic Activity: FeP Nanowire Array as the Active Phase

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]‐hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale‐up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β‐FeOOH NA/Ti precursor through a low‐temperature phosphidation reaction. When applied as self‐supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm², respectively. The excellent electrocatalytic performance is promising for applications as non‐noble‐metal HER catalyst with a high performance–price ratio in electrochemical water splitting for large‐scale hydrogen fuel production.     

有机膦酸盐衍生的氮掺杂的磷酸钴/碳纳米管杂化材料作为高效氧还原电催化剂（英文）

随着环境污染和能源危机的日益严重,探索高效的非贵金属氧还原电催化剂来替代商业Pt/C迫在眉睫.其中,报道比较多的是具有钴基活性物种和氮掺杂碳的复合材料例如Co-Nx-C, Co3O4/GO, Co-N/CNT等,该复合材料具有高导电性、良好的稳定性和优异的催化活性.与其他钴基催化剂相比,磷酸钴由于其成本低廉,对环境友好,多功能的优良特性,已被广泛应用于催化、吸附、分离及储能等领域,在电催化方面也有极大的应用潜力.研究表明,磷酸基团不仅可以充当质子受体,也会诱导局部钴原子的几何结构发生扭曲,从而有利于水分子的吸附并促进析氧反应的发生.此外,磷酸钴也被证实具有一定的氧还原活性.尽管磷酸钴电催化剂的研究已经取得了一定进展,磷酸根有利于质子传输,但是其导电性很差,不利于电荷的转移和传输,使得其电催化活性不高.将磷酸钴和导电碳材料复合是解决问题的有效方法.而且,磷酸钴在碱性溶液中并不稳定,极大限制了其在电催化氧还原中的应用.金属有机膦酸盐是一类包含金属离子和有机膦酸配体的杂化材料,通过简单的焙烧便可以很容易地得到金属无机磷酸盐,并且在焙烧过程中氮掺杂的碳也会原位产生,并包覆在磷酸钴的表面,使得其导电性和催化活性大大提高.为此,本研究组制备了有机膦酸钴衍生的磷酸钴和氮磷掺杂的石墨烯的复合材料并用于电催化氧还原和析氧反应,所得到的材料导电性和稳定性良好,然而,该催化剂的表观活性与商业Pt/C相比仍有较大差距,且使用有机膦酸钴作为前驱体对活性的影响也不甚清楚.因此,本文采用含氮的有机膦酸配体乙二胺四亚甲基膦酸钠(EDTMPS)为磷源制备了氮掺杂的磷酸钴/碳纳米管杂化材料(CoPiC-N/CNT-3),其催化活性和稳定性良好,并进一步探讨了各种不同因素对电催化活性的影响.XRD和TEM结果表明,用这种方法得到的磷酸钴(CoPiC)为Co2P2O7物相,与磷酸二氢钠为磷源制备得到的CoPi相比,CoPiC的表面有石墨化碳层的存在, EDS图谱表明, Co, P, C, N均匀地掺杂到复合材料的骨架结构中.Raman光谱结果表明,石墨化碳层的存在和适量的碳纳米管的引入均可以增强复合材料的石墨化程度并提高了导电性,而氮掺杂导致其缺陷位点增多.XPS结果进一步表明,有机膦酸钴可以作为前驱体可制得氮掺杂的磷酸钴/碳纳米管杂化材料.电催化反应测试表明, CoPi C-N/CNT-3的氧还原活性与商业Pt/C相当,其遵循的是4电子的反应路径,而且抗甲醇氧化能力和稳定性均优于Pt/C.原因主要归结于以下几点:(1)磷酸钴颗粒与氧化碳纳米管的协同作用可以显著增强氧还原催化活性,引入的碳纳米管可以克服磷酸钴导电性差的缺陷;(2)磷酸钴在复合材料中分散均匀,使得可以充分利用催化剂的活性位点;(3)氮掺杂可以调变材料的电子结构,从而改善催化活性;(4)石墨化碳层的存在可以改善材料的电子导电性和稳定性,有利于电子转移并可以保护磷酸钴颗粒在催化氧还原反应过程中不被电解液腐蚀.可见,所制有机膦酸衍生的氮掺杂的磷酸钴/碳纳米管杂化材料有望替代Pt/C催化剂,并推动清洁可再生能源领域的相关研究.     

Enhanced photoelectrocatalytic performance of nanoporous WO3 photoanode by modification of cobalt–phosphate (Co–Pi) catalyst

Nanoporous WO₃ photoanode modified with cobalt–phosphate (Co–Pi) catalyst was synthesized in this study. The nanoporous WO₃ was prepared by anodization of W foil following a photo-assisted electrodeposition of Co–Pi catalyst. The presence of Co–Pi catalyst obviously facilitated the charge transfer and reduced the recombination of photoexcited electron/hole by forming an adequate junction between the catalyst and the nanoporous WO₃. The photocurrent density of nanoporous WO₃/Co–Pi was found to be 1.4 mA/cm² at 0.8 V which was 20 % higher than nanoporous WO₃, and the nanoporous WO₃/Co–Pi photoanode is also more stable for long-term application.     

Cobalt Carbonate Hydroxide Nanowire Array on Ti Mesh: An Efficient and Robust 3D Catalyst for On‐Demand Hydrogen Generation from Alkaline NaBH4 Solution

In this work, for the first time, a cobalt carbonate hydroxide (Co(CO₃)_0.5(OH)?0.11 H₂O) nanowire array on Ti mesh (CHNA/Ti) was applied to drive the dehydrogenation of alkaline NaBH₄ solution for on‐demand hydrogen production. Compared with other nanostructured Co‐based catalyst systems, CHNA/Ti can be activated more quickly and separated easily from fuel solutions. This self‐supported cobalt salt nanowire array catalyst works as an efficient and robust 3D catalyst for the hydrolysis reaction of NaBH₄ with a hydrogen generation rate of 4000 mL min^?1 g_Co^?1 and a low apparent activation energy of 39.78 kJ mol^?1 and offers an attractive system for on‐demand hydrogen generation.     

Strong‐Coupled Cobalt Borate Nanosheets/Graphene Hybrid as Electrocatalyst for Water Oxidation Under Both Alkaline and Neutral Conditions

Developing highly active catalysts for the oxygen evolution reaction (OER) is of paramount importance for designing various renewable energy storage and conversion devices. Herein, we report the synthesis of a category of Co‐Pi analogue, namely cobalt‐based borate (Co‐B_i) ultrathin nanosheets/graphene hybrid by a room‐temperature synthesis approach. Benefiting from the high surface active sites exposure yield, enhanced electron transfer capacity, and strong synergetic coupled effect, this Co‐B_i NS/G hybrid shows high catalytic activity with current density of 10 mA cm^?2 at overpotential of 290 mV and Tafel slope of 53 mV dec^?1 in alkaline medium. Moreover, Co‐B_i NS/G electrocatalysts also exhibit promising performance under neutral conditions, with a low onset potential of 235 mV and high current density of 14.4 mA cm^?2 at 1.8 V, which is the best OER performance among well‐developed Co‐based OER electrocatalysts to date. Our finding paves a way to develop highly active OER electrocatalysts.     

Cobalt complexes based on hyperbranched salicylaldimine ligands as catalyst precursors for ethylene oligomerization

Three hyperbranched salicylaldimine ligands with tetradecyl as core, with hexadecyl as core and with octadecyl as core were synthesized in good yields. These ligands were reacted with cobalt chloride hexahydrate to form three complexes ( C1 – C3 ). The compounds were characterized using Fourier transform infrared, ¹H NMR, mass and UV spectroscopies and thermogravimetric and differential thermal analyses. The catalytic properties of the hyperbranched cobalt complexes were evaluated for ethylene oligomerization. The effects of solvent and reaction parameters (Al/Co molar ratio, temperature and reaction pressure) on ethylene oligomerization were studied using the cobalt complex C3 as pre‐catalyst and methylaluminoxane (MAO) as co‐catalyst. Under these conditions ([Co] = 5 μmol, Al/Co = 500, 25 °C, 0.5 MPa ethylene, 30 min), the catalytic activity of complex C3 in toluene was 1.85 × 10⁵ g (mol Co)⁻¹ h⁻¹ and the selectivity for C₈₊ oligomers was 55.72%. The complex structure also had a significant influence on both the catalytic activity and selectivity. All three cobalt complexes, activated with MAO, showed moderate activities towards ethylene oligomerization and the activity of cobalt complex C1 was up to 1.99 × 10⁵ g (mol Co)⁻¹ h⁻¹. The kinds of metal center of complexes (cobalt complex C1 and nickel complex with tetradecyl as core) and their catalytic properties were investigated in detail under the same conditions.     

A Molecular Cobalt Hydrogen Evolution Catalyst Showing High Activity and Outstanding Tolerance to CO and O2

There is a demand to develop molecular catalysts promoting the hydrogen evolution reaction (HER) with a high catalytic rate and a high tolerance to various inhibitors, such as CO and O₂. Herein we report a cobalt catalyst with a penta‐dentate macrocyclic ligand ( 1‐Co ), which exhibits a fast catalytic rate (TOF=2210 s^?1) in aqueous pH 7.0 phosphate buffer solution, in which proton transfer from a dihydrogen phosphate anion (H₂PO₄^?) plays a key role in catalytic enhancement. The electrocatalyst exhibits a high tolerance to inhibitors, displaying over 90 % retention of its activity under either CO or air atmosphere. Its high tolerance to CO is concluded to arise from the kinetically labile character of undesirable CO‐bound species due to the geometrical frustration posed by the ligand, which prevents an ideal trigonal bipyramid being established.     

Earth‐Abundant Oxygen Evolution Catalysts Coupled onto ZnO Nanowire Arrays for Efficient Photoelectrochemical Water Cleavage

ZnO has long been considered as a model UV‐driven photoanode for photoelectrochemical water splitting, but its performance has been limited by fast charge‐carrier recombination, extremely poor stability in aqueous solution, and slow kinetics of water oxidation. These issues were addressed by applying a strategy of optimization and passivation of hydrothermally grown 1D ZnO nanowire arrays. The length and diameter of bare ZnO nanowires were optimized by varying the growth time and precursor concentration to achieve optimal photoelectrochemical performance. The addition of earth‐abundant cobalt phosphate (Co‐Pi) and nickel borate (Ni‐B) oxygen evolution catalysts onto ZnO nanowires resulted in substantial cathodic shifts in onset potential to as low as about 0.3 V versus the reversible hydrogen electrode (RHE) for Ni‐B/ZnO, for which a maximum photocurrent density of 1.1 mA cm^?2 at 0.9 V (vs. RHE) with applied bias photon‐to‐current efficiency of 0.4 % and an unprecedented near‐unity incident photon‐to‐current efficiency at 370 nm. In addition the potential required for saturated photocurrent was dramatically reduced from 1.6 to 0.9 V versus RHE. Furthermore, the stability of these ZnO nanowires was significantly enhanced by using Ni‐B compared to Co‐Pi due to its superior chemical robustness, and it thus has additional functionality as a stable protecting layer on the ZnO surface. These remarkable enhancements in both photocatalytic activity and stability directly address the current severe limitations in the use of ZnO‐based photoelectrodes for water‐splitting applications, and can be applied to other photoanodes for efficient solar‐driven fuel synthesis.     

Co掺杂SAPO-5分子筛制备及其催化氧气氧化环己烷反应性能(英文)

环己醇和环己酮(KA油)是制备尼龙所需材料己二酸和己内酰胺的重要中间体,也可用作油漆、农药和染料等的溶剂以及染色和褪光丝的均化剂等.工业上制取KA油的方法主要为苯酚加氢法、环己烯水合法和环己烷氧化法,其中环己烷氧化法最为普遍,是非常重要的工业过程.为获得适宜的KA油选择性,工业上普遍采用Co盐为催化剂,将环己烷氧化单程转化率控制在5.0%以下,从而使得产物选择性达到70%以上.该环己烷氧化制KA油过程不仅生产效率较低,而且所用均相催化剂因分离困难而不能重复使用.因此,当前关于环己烷氧化反应催化剂的研究均是围绕多相催化剂进行.氧气选择性氧化环己烷反应因具有更高的原子经济性而逐渐成为环己烷氧化法制KA油研究中最具挑战性的课题.该反应是自由基机理,而Co~(2+),Cr~(3+),Mn~(2+)和Ce~(2+)等金属离子可以促进自由基链反应,因此含有这些金属的多相催化剂被广泛用于该反应.另一方面,AlPO-n系列分子筛由于具有特殊的孔结构和一定的表面酸性,在催化反应中显示出较大的应用潜力.如果进行杂原子掺杂,通过改变分子筛骨架的电荷平衡,可以有效提高其表面酸性.例如磷酸硅铝分子筛(SAPO-5)具有中等强度的酸性和良好的择形性,因而作为固体酸催化剂广泛用于乙醇脱水、甲醇制烯烃、丙烯聚合和苯乙烯环氧化等反应,表现出较高的选择性和良好的稳定性.本文以传统均相Co盐催化剂的多相化为出发点,制备了Co掺杂SAPO-5与分子筛催化剂(Co-SAPO-5),考察了Co掺杂量对催化剂结构、表面性质以及氧气选择性氧化环己烷反应性能的影响.结果表明,一部分Co进入分子筛骨架,同时有少量Co以氧化钻形式高度分散在SAPO-5表面.Co掺杂对SAOP-5催化剂比表面积没有显著影响,但可使其孔体积减小.相反,Co掺杂可以提高SAOP-5分子筛表面B酸性位数量和总酸量.活性测试结果表明,环己烷转化率随着Co-SAPO-5催化剂中Co含量的增加而增加,但KA油选择性在转化率高于6.3%时急剧下降.还考察了反应温度、反应时间、初始氧气压力和催化剂用量对Co-SAPO-5分子筛催化剂性能的影响,得到了最优反应条件.以Co-SAPO-5-0.2(Co/Si摩尔比为0.2)分子筛为催化剂时,KA油总收率最高可达7.8%.另外,Co-SAPO-5催化剂在环己烷氧化反应中显示出很好的稳定性,Co-SAPO-5-0.2催化剂套用6次后活性几乎没有变化.     

Insight into the improvement mechanism of Co−Pi-modified hematite nanowire photoanodes for solar water oxidation

The composite photoanodes composed by cobalt phosphate catalyst (Co−Pi) modified semiconductor have been widely used for solar water splitting, but the improvement mechanism has not been experimentally confirmed. Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co−Pi catalyst on hematite nanowire photoanode. It is found that under illumination the Co−Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co−Pi layer by increasing the electrical conductivity of the composite structure under a low potential. The Co−Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential. These results provide important new understanding of the performance improvement mechanism for the Co−Pi-modified semiconductor nanowire composite photoanodes.     

Liquid Phase Hydrogenolysis of Biomass‐derived Lactate to 1,2‐Propanediol over Silica Supported Cobalt Nanocatalyst

Liquid phase hydrogenolysis of ethyl lactate to 1,2‐propanediol was performed over silica supporting cobalt catalysts prepared by two different methods: precipitation‐gel (PG) technique and deposition‐precipitation (DP) procedure. The cobalt species (Co₃O₄/cobalt phyllosilicate) present in the corresponding calcined PG and DP catalysts were different as a consequence of the preparation methods, and Co OH Co olation and Si O Co oxolation molecular mechanisms were employed to elucidate the chemical phenomena during the different preparation procedures. In addition, the texture (BET), reduction behavior (TPR and in‐situ XRD), surface dispersion and state of cobalt species (XPS), and catalytic performance differ greatly between the samples. Because of small particle size, high dispersion of cobalt species and facile reducibility, the Co/SiO₂ catalyst prepared by precipitation‐gel method presented a much higher activity than the catalyst prepared by deposition‐precipitation method. Metallic cobalt is assumed to be the catalytically active site for the hydrogenolysis reaction according to the catalytic results of both cobalt samples reduced at different temperatures and the structure changes after reaction.     

Ionic Polymer Microspheres Bearing a CoIII–Salen Moiety as a Bifunctional Heterogeneous Catalyst for the Efficient Cycloaddition of CO2 and Epoxides

We report a unique strategy to obtain the bifunctional heterogeneous catalyst TBB‐Bpy@Salen‐Co (TBB=1,2,4,5‐tetrakis(bromomethyl)benzene, Bpy=4,4’‐bipyridine, Salen‐Co=N,N’‐bis({4‐dimethylamino}salicylidene)ethylenediamino cobalt(III) acetate) by combining a cross‐linked ionic polymer with a Co^III–salen Schiff base. The catalyst showed extra high activity for CO₂ fixation under mild, solvent‐free reaction conditions with no requirement for a co‐catalyst. The synthesized catalyst possessed distinctive spherical structural features, abundant halogen Br^? anions with good leaving group ability, and accessible Lewis acidic Co metal centers. These unique features, together with the synergistic role of the Co and Br^? functional sites, allowed TBB‐Bpy@Salen‐Co to exhibit enhanced catalytic conversion of CO₂ into cyclic carbonates relative to the corresponding monofunctional analogues. This catalyst can be easily recovered and recycled five times without significant leaching of Co or loss of activity. Moreover, based on our experimental results and previous work, a synergistic cycloaddition reaction mechanism was proposed.     

Pyrolysis of Animal Bones with Vitamin B12: A Facile Route to Efficient Transition Metal–Nitrogen–Carbon (TM‐N‐C) Electrocatalysts for Oxygen Reduction

By pyrolyzing cattle bones, hierarchical porous carbon (HPC) networks with a high surface area (2520 m² g^?1) and connected pores were prepared at a low cost and large scale. Subsequent co‐pyrolysis of HPC with vitamin B12 resulted in the formation of three‐dimensional (3D) hierarchically structured porous cobalt–nitrogen–carbon (Co‐N‐HPC) electrocatalysts with a surface area as high as 859 m² g^?1 as well as a higher oxygen reduction reaction (ORR) electrocatalytic activity, better operation stability, and higher tolerance to methanol than the commercial Pt/C catalyst in alkaline electrolyte.     

Cobalt‐Catalyzed,Aminoquinoline‐Directed C(sp2)H Bond Alkenylation by Alkynes

A method for cobalt‐catalyzed, aminoquinoline‐ and picolinamide‐directed C(sp²)? H bond alkenylation by alkynes was developed. The method shows excellent functional‐group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)₂?4 H₂O catalyst, Mn(OAc)₂ co‐catalyst, and oxygen (from air) as a terminal oxidant.     

Molecular Cobalt Clusters as Precursors of Distinct Active Species in Electrochemical,Photochemical, and Photoelectrochemical Water Oxidation Reactions in Phosphate Electrolytes

Three cobalt model molecular compounds, Co‐cubane ([Co₄(µ₃‐O)₄(µ‐OAc)₄py₄]), Co‐trimer ([Co₃(μ₃‐O)(µ‐OAc)₆py₃]PF₆), and Co‐dimer ([Co₂(μ‐OH)₂(µ‐OAc)(OAc)₂py₄]PF₆), are investigated as water oxidation reaction (WOR) catalysts, using electrochemical, photochemical, and photoelectrochemical methodologies in phosphate electrolyte. The actual species contributing to the catalytic activity observed in the WOR are derived from the transformation of these cobalt compounds. The catalytic activity observed is highly dependent on the initial compound structure and on the particular WOR methodology used. Co‐cubane shows no activity in the electrochemical WOR and negligible activity in the photochemical WOR, but is active in the photoelectrochemical WOR, in which it behaves as a precursor to catalytically active species. Co‐dimer also shows no activity in the electrochemical WOR, but behaves as a precursor to catalytically active species in both the photochemical and photoelectrochemical WOR experiments. Co‐trimer behaves as a precursor to catalytically active species in all three of the WOR methodologies.     

Effect of support and cobalt precursors on the activity of Co/AlPO4 catalysts in Fischer–Tropsch synthesis

Cobalt supported on amorphous aluminum phosphate (Co/AlPO₄) catalysts were prepared by the impregnation method using three different cobalt precursors such as cobalt nitrate, acetate and chloride to elucidate the activity of Fischer–Tropsch synthesis. The use of AlPO₄ as a support for cobalt-based catalysts exhibits better catalytic performance during FTS reaction than the corresponding Co/Al₂O₃ catalyst. TPR results also suggest that the reducibility of the catalysts varies with the nature of cobalt precursors employed during the impregnation on AlPO₄ support. The Co/AlPO₄ catalyst prepared from cobalt nitrate shows higher CO conversion and C₈+ selectivity than the others due to the facile formation of homogeneous cobalt particles with proper electronic characters and high reducibility. Interestingly, all Co/AlPO₄ showed a growth of filamentous carbon initiated from the large mobile cobalt particles during the reaction. The differences in catalytic properties of Co/AlPO₄ are mainly attributed to the cobalt particle size, reducibility with different electronic states of metallic cobalt, pore diameter of AlPO₄ and formation of filamentous carbon.     

Cobalt(II) acetylacetonate complex immobilized on aminosilane‐modified SBA‐15 as an efficient catalyst for epoxidation of trans‐stilbene with molecular oxygen

From environmental and economic points of view, it is highly desirable to develop a clean and efficient catalytic process to produce epoxides. An attractive approach is to use a solid, recyclable catalyst and molecular oxygen as the oxidant without any sacrificial reductant or other additives. Nonetheless, the catalysts reported up to now still cannot balance catalytic activity with epoxide selectivity. It is of great importance to explore novel catalysts with both high activity and selectivity for the epoxidation of olefins. In this work, cobalt(II) acetylacetonate (Co(acac)₂) was covalently bonded to the silica surface of SBA‐15 molecular sieve by multi‐step grafting using 3‐aminopropytrimethoxysilane (APTS) as coupling agent. Characterizations with nitrogen physisorption, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis suggested that the metal complex was successfully immobilized on the aminosilane‐modified SBA‐15 surface and the channel structure remained intact. The synthesized Co(acac)₂APTS@SBA‐15 catalyst was used in the epoxidation of trans‐stilbene (TS) with molecular oxygen. Compared to the sample prepared by the impregnation method as well as Co(acac)₂ solutions under the same reaction conditions, the Co(acac)₂ immobilized catalyst exhibited remarkably higher TS conversion and trans‐stilbene oxide (TSO) selectivity. An increase in TS conversion with Co content was observed when the Co loading was lower than 0.70% and the 0.70Co(acac)₂APTS@SBA‐15 sample exhibited the best catalytic performance. Up to 50.1% of TS conversion could be achieved within 6 h, affording TSO selectivity as high as 96.7%. The superior catalytic performance of this particular catalyst is attributed to the high activity of the immobilized Co(acac)₂ species on SBA‐15. Copyright © 2016 John Wiley & Sons, Ltd.     

Cobalt‐Catalyzed,Aminoquinoline‐Directed C(sp2)?H Bond Alkenylation by Alkynes

A method for cobalt‐catalyzed, aminoquinoline‐ and picolinamide‐directed C(sp²) H bond alkenylation by alkynes was developed. The method shows excellent functional‐group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)₂⋅4 H₂O catalyst, Mn(OAc)₂ co‐catalyst, and oxygen (from air) as a terminal oxidant.     

Coordination Chemistry of [Co(acac)2] with N‐Doped Graphene: Implications for Oxygen Reduction Reaction Reactivity of Organometallic Co‐O4‐N Species

Hybridization of organometallic complexes with graphene‐based materials can give rise to enhanced catalytic performance. Understanding the chemical structures within hybrid materials is of primary importance. In this work, archetypical hybrid materials are synthesized by the reaction of an organometallic complex, [Co^II(acac)₂] (acac=acetylacetonate), with N‐doped graphene‐based materials at room temperature. Experimental characterization of the hybrid materials and theoretical calculations reveal that the organometallic cobalt‐containing species is coordinated to heterocyclic groups in N‐doped graphene as well as to its parental acac ligands. The hybrid material shows high electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, and superior durability and methanol tolerance to a Pt/C catalyst. Based on the chemical structures and ORR experiments, the catalytically active species is identified as a Co‐O₄‐N structure.     

Monolithically Integrated Spinel MxCo3−xO4 (M=Co,Ni, Zn) Nanoarray Catalysts: Scalable Synthesis and Cation Manipulation for Tunable Low‐Temperature CH4 and CO Oxidation

A series of large scale M_xCo_3?xO₄ (M=Co, Ni, Zn) nanoarray catalysts have been cost‐effectively integrated onto large commercial cordierite monolithic substrates to greatly enhance the catalyst utilization efficiency. The monolithically integrated spinel nanoarrays exhibit tunable catalytic performance (as revealed by spectroscopy characterization and parallel first‐principles calculations) toward low‐temperature CO and CH₄ oxidation by selective cation occupancy and concentration, which lead to controlled adsorption–desorption behavior and surface defect population. This provides a feasible approach for scalable fabrication and rational manipulation of metal oxide nanoarray catalysts applicable at low temperatures for various catalytic reactions.