通过与氧化石墨烯复合增强金属有机框架材料MOF(Ni)-74的电催化析氢性能

采用溶剂热法制备了金属有机框架材料 MOF(Ni)-74及其与氧化石墨烯(GO)的复合材料 MOF(Ni)-GO,并利用线性伏安扫描(LSV)等电化学方法在 N2饱和的0.5 mol/L H2SO4溶液中对材料的电催化性能进行了检测.实验结果表明,GO 的掺杂能显著提升金属有机框架材料 MOF(Ni)-74的电催化活性.其中 GO 含量为8%时,所得复合材料表现出最好的电催化析氢活性,起始电势仅为-0.462 V,塔菲尔斜率为110 mV/dec,同时该材料也表现出很好的电化学稳定性.     

Ni(OH)_2/RGO复合材料的化学沉淀-回流法制备和放电性能

以氧化石墨(GO)和NiSO_4·6H_2O为前驱体,氨水为沉淀剂,用化学沉淀-回流法制备Ni(OH)_2/还原氧化石墨烯(RGO)复合材料,用XRD、SEM表征材料的结构和表面微观形貌,用循环伏安(CV)、恒电流充放电和电化学阻抗(EIS)测试电极材料的电化学性能,研究了GO:Ni(OH)_2质量比和氨水浓度对复合材料结构、形貌和电化学性能的影响。结果表明:所制备的β-Ni(OH)_2/RGO复合材料为Ni(OH)_2纳米片与RGO片相互插层的结构,当氨水的浓度为3 mol/L,GO:Ni(OH)_2=1:8(质量比)时复合电极材料在0.2C的放电比容量高达334.9 mAh/g,5C的放电比容量为260.2 mAh/g,保持在β-Ni(OH)_2理论比容量的90%,表现出良好的倍率性能和循环性能。     

MOF衍生的Ni/C的制备及其氮还原性能研究

电催化氮气还原反应(NRR)因可在常温常压下高效固氮而被认为是一种前景广阔的合成氨的方法，有望替代传统Haber-Bosch工艺。电催化剂的设计和制备是提升NRR性能的关键因素。采用水热法制备了金属-有机框架材料(MOF),通过高温热处理获得MOF衍生的片状Ni/C纳米材料，将其用于NRR反应的电催化剂。研究发现，在0.1mol/L KOH电解液中，电位为-0.9V时Ni/C纳米材料最大的氨产率为66.57μg/(h·mg),法拉第效率高达33.67%,且显示了良好的电化学稳定性。     

MOF复合材料的制备及应用研究进展

金属有机骨架材料(MOFs)是一种由金属离子与有机配体自组装而成的新型多孔骨架材料。将高孔隙率、结构可调的MOFs材料与其他功能材料结合构建复合材料,可以发挥超于原材料的优良特性。金属有机骨架(MOF)复合材料作为新型功能材料发展迅速,并应用于气体吸附、分离与存储、催化、气体传感、药物传输等方面,甚至因两种材料间的相互作用而产生的协同效应将应用领域延伸至燃料电池、电催化等。简单介绍了MOF复合材料的种类,与MOFs构建复合材料的材料包括碳基材料、有机高分子材料、多金属氧酸盐、金属纳米颗粒、金属氧化物、SiO_2材料、量子点、生物酶等。分析了各种MOF复合材料在气体吸附与存储、多相催化、化学传感等领域的应用。最后,对MOF复合材料的应用前景进行了展望,功能化、低成本、易于工业化生产的MOF复合材料是今后研究开发的方向。     

FeOOH-Ni(OH)2复合材料的制备及其电催化析氧性能

以碳纤维布（CFC）为基底,通过两步法(恒电流电沉积法、溶剂热法)成功制备了FeOOH-Ni(OH)₂复合材料。与FeOOH和Ni(OH)₂相比,该FeOOH-Ni(OH)₂复合材料作为电催化剂时,电催化析氧反应(OER)活性显著提高。在1 mol/L KOH电解质溶液中,达到10 mA·cm?2电流密度时所需要的过电位仅为270 mV,Tafel斜率为78 mV/dec,电化学阻抗谱进一步揭示了电解过程中良好的动力学特性。FeOOH-Ni(OH)₂复合材料在碱性介质中具有优异的稳定性,其在高电流密度下(50 mA·cm?2)的过电势经过连续24 h的测试之后几乎没有发生明显变化。FeOOH和Ni(OH)₂之间的强电子相互作用和协同效应有效提高了电导性,促进了电荷转移;此外,这种核壳结构有效增强了电催化活性面积,进而增强了其电催化析氧性能。      

还原剂对Ni(OH)_2/还原氧化石墨烯复合材料结构及电化学性能的影响

为研究还原剂对Ni(OH)_2/还原氧化石墨烯(RGO)复合材料结构及电化学性能的影响,首先以氧化石墨烯(GO)和硝酸镍作前驱体,采用水热法制备了Ni(OH)_2/RGO复合材料;然后,利用XRD、SEM和Raman光谱仪表征了复合材料的结构和形貌,并采用循环伏安法、恒流充放电曲线和电化学阻抗谱研究了复合材料的电化学性能。结果表明:以(NH2)2CSO2作还原剂时,制备的β-Ni(OH)_2/RGO复合材料为RGO纳米片与Ni(OH)_2纳米片相互插层的结构;在电解液(6mol/L KOH溶液)中,0.2C放电倍率时β-Ni(OH)_2/RGO复合材料的比容量高达341.0mAh/g,10.0C放电倍率为时复合材料的比容量为242.2mAh/g,仍能保持β-Ni(OH)_2理论比容量的83.8%。所得结论表明制备的Ni(OH)_2/RGO复合材料显现出良好的电化学性能。     

两种方法还原GO制备RGO/MOF基复合相变材料及导热性能

对氧化石墨烯(GO)分别采用热还原(1200℃)和还原剂还原(水合肼)方法制备了两种还原氧化石墨烯(RGO)粉体。进而采用真空浸渍法，分别制备质量含量5%RGO,35%金属有机框架材料[MOF,MIL-101(Cr)-NH₂]和60%石蜡(PW)的复合相变材料(CPCM)。采用扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(FT-IR)和拉曼光谱对两种RGO的结构进行了考察，并用Hot Disk比较两种RGO对MOF基复合相变材料热导率的增强作用。结果表明：两种方法均有利于GO中含氧官能团的去除以及sp²杂化碳晶格有序度的变化，GO得到了有效还原。然而，负载两种RGO的金属有机框架材料基复合相变材料表现出了不同的导热性能。在常温下，MIL-101(Cr)-NH₂和纯石蜡的热导率分别约为0.21W/(m·K)和0.25W/(m·K)。加载5%还原剂法得到的RGO/MOF基复合相变材料的热导率值达到1.43W/(m·K),远远高于加载5%热还原法得到的RGO/MOF基复合相变材料的值[0.33W/(m·K)]。因此，与低...     

GO/MOF复合材料的制备及其吸附苯和乙醇性能（英文）

采用溶剂热法制备了金属有机骨架-氧化石墨烯(MOF/GO)复合材料,通过氮吸附/脱附、红外光谱对其比表面积和孔结构、表面官能团进行了表征,考察了其吸附苯和乙醇的性能。结果表明,当氧化石墨烯的添加量为5.25 wt%时,复合材料的比表面积和孔容最大。该材料对苯和乙醇有很高的吸附容量,其最大吸附容量可分别达到72和77 cm~3/g。MOF-5/GO复合材料吸附挥发性有机物(VOCs)的容量不仅受孔结构的影响,其表面特性也对吸附性能有重要作用。氧化石墨烯含量为3.5 wt%的GO/MOF复合材料对乙醇的吸附容量显著增强是由于其含有大量的含氧官能团。     

用于铅离子检测的Cu-MOF电化学传感器构建及性能研究

通过简单的水热反应制备了一种以铜为中心金属，以2-氨基对苯二甲酸为有机配体的金属有机框架材料(MOF)。用X射线衍射仪、傅里叶变换红外光谱仪、气体物理吸附仪和扫描电子显微镜等对其结构、形貌、比表面积等进行了表征分析。以Cu-MOF为活性材料构建电化学传感器，利用差示脉冲阳极溶出伏安法对样品中Pb²⁺进行检测，系统考察了沉积电位、沉积时间、pH、扫描速率等对目标物检测的影响。实验发现，在最佳条件下，Cu-MOF对3nmol/L～7mmol/L范围内的铅离子表现出良好的线性关系，Pb²⁺的检测限为0.025nmol/L。同时，还研究了传感器的抗干扰能力及对真实样品的检测效果。实验结果表明，Cu-MOF对Pb²⁺的检测显示出良好的灵敏度、选择性、再现性，以及较宽的线性检测范围和较低的检测限，是一种极具应用潜力的电化学传感器活性材料。     

Ni (OH)2-碳纳米管-还原氧化石墨烯复合材料的制备及电化学性能

利用简单易行的一步水热法制备了Ni（OH）₂-碳纳米管-还原氧化石墨烯（Ni（OH）₂-CNTs-RGO）三元复合材料,研究了不同水热反应温度对三元复合材料性能的影响。采用XRD、FTIR、Raman、X射线光电子能谱（XPS）、SEM及TEM对Ni（OH）₂-CNTs-RGO复合材料的结构和表面微观形貌进行表征。利用循环伏安（CV）、电化学交流阻抗（EIS）和恒电流充放电测试了复合电极材料的电化学性能。研究结果表明,当反应温度为120℃时,所制备的Ni（OH）₂-CNTs-RGO复合材料具有大的比表面积和三维网状结构,复合材料中六角形的β-Ni（OH）₂纳米片和CNTs均匀分散在RGO片层表面,有效阻止了RGO的团聚。Ni（OH）₂-CNTs-RGO复合电极材料在充电倍率为0.2 C时,放电比容量达到362.8 mAh/g,5 C时放电比容量为286.2 mAh/g,仍大于Ni（OH）₂在0.2 C时的放电比容量,表明CNTs与RGO的协同作用有效提高了电极材料的导电性和活性物质的利用率,最终提升了Ni（OH）₂-CNTs-RGO复合材料的倍率性能。     

Self‐Sacrificial Template‐Directed Vapor‐Phase Growth of MOF Assemblies and Surface Vulcanization for Efficient Water Splitting

Direct use of metal–organic frameworks (MOFs) with robust pore structures, large surface areas, and high density of coordinatively unsaturated metal sites as electrochemical active materials is highly desirable (rather than using as templates and/or precursors for high‐temperature calcination), but this is practically hindered by the poor conductivity and low accessibility of active sites in the bulk form. Herein, a universal vapor‐phase method is reported to grow well‐aligned MOFs on conductive carbon cloth (CC) by using metal hydroxyl fluorides with diverse morphologies as self‐sacrificial templates. Specifically, by further partially on‐site generating active Co₃S₄ species from Co ions in the echinops‐like Co‐based MOF (EC‐MOF) through a controlled vulcanization approach, the resulting Co₃S₄/EC‐MOF hybrid exhibits much enhanced electrocatalytic performance toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with overpotentials of 84 and 226 mV required to reach a current density of 10 mA cm^?2, respectively. Density functional theory (DFT) calculations and experimental results reveal that the electron transfer between Co₃S₄ species and EC‐MOF can decrease the electron density of the Co d‐orbital, resulting in more electrocatalytically optimized adsorption properties for Co. This study will open up a new avenue for designing highly ordered MOF‐based surface active materials for various electrochemical energy applications.     

A sensitive electrochemical detection of hydroquinone using newly synthesized α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-graphene oxide nanocomposite as an electrode material

This article presents the effect of hematite phase iron oxide (α-Fe₂O₃) on the electrocatalytic activity of graphene oxide (GO) for electrochemical detection of hydroquinone in aqueous solution. The different weight percentage (wt%) (1, 2 and 3%) of α-Fe₂O₃ added GO nanocomposites were synthesized by wet-impregnation method. The cyclic voltammetry studies using 2% α-Fe₂O₃-GO modified glassy carbon electrodes was found to exhibit an excellent electrocatalytic activity than α-Fe₂O₃ and GO electrodes that may be due to the synergistic effect of α-Fe₂O₃nanoparicles and GO sheet. In addition, the modified electrode exhibited a good reproducibility as well as long-term stability. Hence, the 2% α-Fe₂O₃-GO can be a promising catalytic material for electrochemical sensor applications.     

多孔Ni-WC复合电极的制备及其在酸性溶液中的电催化析氢性能

目前,关于多孔Ni-WC电极的电催化析氢(HER)性能的报道较少。以多孔海绵镍为基体,采用复合电沉积制备多孔Ni-(WC)x复合电极。运用扫描电镜(SEM)和X射仪线衍射仪(XRD)表征电极的表面形貌和微观结构,通过阴极极化、电化学阻抗(EIS)、循环伏安、计时电流法研究多孔Ni-(WC)x电极在0.5 mol/L H2SO4溶液中的电催化析氢性能。结果表明:与多孔基体Ni电极相比,多孔Ni-(WC)x电极具有较低的析氢过电位、较低的电化学反应阻抗、较小的表观活化能以及较大的交换电流密度;随着镀液中WC浓度的升高,所制备的多孔Ni-(WC)x电极的电催化析氢活性增强,其中Ni-(WC)40电极的表观交换电流密度是多孔Ni基体电极的966.7倍,其表观活化能为5.95 kJ/mol,并具有较好的耐蚀性和析氢稳定性。     

Single-Site Metal–Organic Framework and Copper Foil Tandem Catalyst for Highly Selective CO2 Electroreduction to C2H4

Tandem catalysis is a promising way to break the limitation of linear scaling relationship for enhancing efficiency, and the desired tandem catalysts for electrochemical CO₂ reduction reaction (CO₂RR) are urgent to be developed. Here, a tandem electrocatalyst created by combining Cu foil (CF) with a single-site Cu(II) metal–organic framework (MOF), named as Cu–MOF–CF, to realize improved electrochemical CO₂RR performance, is reported. The Cu–MOF–CF shows suppression of CH₄, great increase in C₂H₄ selectivity (48.6%), and partial current density of C₂H₄ at −1.11 V versus reversible hydrogen electrode. The outstanding performance of Cu–MOF–CF for CO₂RR results from the improved microenvironment of the Cu active sites that inhibits CH₄ production, more CO intermediate produced by single-site Cu–MOF in situ for CF, and the enlarged active surface area by porous Cu–MOF. This work provides a strategy to combine MOFs with copper-based electrocatalysts to establish high-efficiency electrocatalytic CO₂RR.     

Porous Microrod Arrays Constructed by Carbon‐Confined NiCo@NiCoO2 Core@Shell Nanoparticles as Efficient Electrocatalysts for Oxygen Evolution

The study of cost‐efficient and high‐performance electrocatalysts for oxygen evolution reaction (OER) has attracted much attention. Here, porous microrod arrays constructed by carbon‐confined NiCo@NiCoO₂ core@shell nanoparticles (NiCo@NiCoO₂/C PMRAs) are fabricated by the reductive carbonization of bimetallic (Ni, Co) metal–organic framework microrod arrays (denoted as NiCo‐MOF MRAs) and subsequent controlled oxidative calcination. They successfully combine the desired merits including large specific surface areas, high conductivity, and multiple electrocatalytic active sites for OER. In addition, the oxygen vacancies in NiCo@NiCoO₂/C PMRAs significantly improve the conductivity of NiCoO₂ and accelerate the kinetics of OER. The above advantages obviously enhance the electrocatalytic performance of NiCo@NiCoO₂/C PMRAs. The experimental results demonstrate that the NiCo@NiCoO₂/C PMRAs as electrocatalysts exhibit high catalytic activity, low overpotential, and high stability for OER in alkaline media. The strategy reported will open up a new route for the fabrication of porous bimetallic composite electrocatalysts derived from MOFs with controllable morphology for electrochemical energy conversion devices.     

Inlaying Ultrathin Bimetallic MOF Nanosheets into 3D Ordered Macroporous Hydroxide for Superior Electrocatalytic Oxygen Evolution

Controllable synthesis of ultrathin metal–organic framework (MOF) nanosheets and rational design of their nano/microstructures in favor of electrochemical catalysis is critical for their renewable energy applications. Herein, an in situ growth method is proposed to prepare the ultrathin NiFe MOF nanosheets with a thickness of 1.5 nm, which are vertically inlaid into a 3D ordered macroporous structure of NiFe hydroxide. The well‐designed composite delivers an efficient electrocatalytic performance with a low overpotential of 270 mV at a current density of 10 mA cm^?2 and stable electrolysis as long as 10 h toward the electrochemical oxygen evolution reaction, much superior to the state‐of‐the‐art RuO₂ electrocatalyst. A comprehensive analysis demonstrates that the excellent performance originates from the desirable combination of the highly exposed active centers in the ultrathin bimetallic MOF nanosheets, effective electron conduction between MOF nanosheets and ordered macroporous hydroxide, and efficient mass transfer across the hierarchically porous hybridization. This study sheds light on the exploration of powerful protocols to gain diverse high‐performance MOF nanosheets and may open a perspective to achieve their efficient electrocatalytic performance.     

A Freestanding 3D Heterostructure Film Stitched by MOF-Derived Carbon Nanotube Microsphere Superstructure and Reduced Graphene Oxide Sheets: A Superior Multifunctional Electrode for Overall Water Splitting and Zn–Air Batteries

Developing a scalable approach to construct efficient and multifunctional electrodes for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) is an urgent need for overall water splitting and zinc–air batteries. In this work, a freestanding 3D heterostructure film is synthesized from a Ni-centered metal−organic framework (MOF)/graphene oxide. During the pyrolysis process, 1D carbon nanotubes formed from the MOF link with the 2D reduced graphene oxide sheets to stitch the 3D freestanding film. The results of the experiments and theoretical calculations show that the synergistic effect of the N-doped carbon shell and Ni nanoparticles leads to an optimized film with excellent electrocatalytic activity. Low overpotentials of 95 and 260 mV are merely needed for HER and OER, respectively, to reach a current density of 10 mA cm⁻². In addition, a high half-wave potential of 0.875 V is obtained for the ORR, which is comparable to that of Pt/RuO₂ and ranks among the top of non-noble-metal catalysts. The use of an “all-in-one” film as the electrode leads to excellent performance of the homemade water electrolyzer and zinc–air battery, indicating the potential of the film for practical applications.     

Ultrathin Ni(0)-Embedded Ni(OH)2 Heterostructured Nanosheets with Enhanced Electrochemical Overall Water Splitting

The efficiency of splitting water into hydrogen and oxygen is highly dependent on the catalyst used. Herein, ultrathin Ni(0)-embedded Ni(OH)₂ heterostructured nanosheets, referred to as Ni/Ni(OH)₂ nanosheets, with superior water splitting activity are synthesized by a partial reduction strategy. This synthetic strategy confers the heterostructured Ni/Ni(OH)₂ nanosheets with abundant Ni(0)-Ni(II) active interfaces for hydrogen evolution reaction (HER) and Ni(II) defects as transitional active sites for oxygen evolution reaction (OER). The obtained Ni/Ni(OH)₂ nanosheets exhibit noble metal-like electrocatalytic activities toward overall water splitting in alkaline condition, to offer 10 mA cm⁻² in HER and OER, the required overpotentials are only 77 and 270 mV, respectively. Based on such an outstanding activity, a water splitting electrolysis cell using the Ni/Ni(OH)₂ nanosheets as the cathode and anode electrocatalysts has been successfully built. When the output voltage of the electrolytic cell is 1.59 V, a current density of 10 mA cm⁻² can be obtained. Moreover, the durability of Ni/Ni(OH)₂ nanosheets in the alkaline electrolyte is much better than that of noble metals. No obvious performance decay is observed after 20 h of catalysis. This facile strategy paves the way for designing highly active non-precious-metal catalyst to generate both hydrogen and oxygen by electrolyzing water at room temperature.     

Electrocatalytic evolution of hydrogen on the NiCu/Al2O3/nano-carbon network composite electrode

We present a way to fabricate the NiCu/Al₂O₃/nano-carbon network (NCN) composite electrode by coelectrodepositing NiCu particles, using a novel conductive alumina/NCN composite material as the support. The morphology, crystalline phases, and compositions are characterized by field-emission scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffraction, and Raman spectroscopy. The electrocatalytic behaviors of this NiCu/Al₂O₃/NCN composite material for hydrogen evolution reaction (HER) in alkaline solution are studied by cathodic polarization curves, electrochemical impedance spectroscopy (EIS), and chronoamperometry. The results show that nickel–copper particles are briefly deposited and uniformly distributed over the carbon layer of the conductive ceramics between alumina grains, in the form of a NiCu solid solution with face-centered cubic structure. The NiCu/Al₂O₃/NCN composite displays a high electrochemical stability in alkaline solution and relatively high electrocatalytic activity for HER due to its relatively high real surface area and high intrinsic electrocatalytic effect of NiCu alloy particles. The associated kinetic parameters of HER are systematically investigated using EIS.