electrocatalyst

电催化剂
  • 文章类型: Journal Article
    所开发的合成金属磷化物的策略通常是麻烦的并且污染环境。在这项工作中,开发了一种超快(30s)准固态微波方法,以构建用Ru(Ru/CoxP-MoP)修饰的磷化钴钼,其特征是具有互连通道的多孔形态。特定的纳米结构有利于质量传输,如电解质气泡转移和暴露丰富的活性位点。此外,金属元素之间的耦合效应,尤其是装饰过的Ru,在提高电催化性能方面也起着举足轻重的作用。受益于成分和特定纳米结构的影响,制备的Ru/CoxP-MoP表现出有效的HER性能,在1mKOH中达到10mAcm-2的电流密度,0.5mH2SO4,含1mKOH和1mPBS的海水,过电位为52、59、55、90mV,和良好的稳定性耦合。这项工作为在能量转换和存储领域设计基于金属磷化物的纳米材料开辟了一条新颖而快捷的途径。
    The developed strategies for synthesizing metal phosphides are usually cumbersome and pollute the environment. In this work, an ultrafast (30 s) quasi-solid-state microwave approach is developed to construct cobalt-molybdenum phosphide decorated with Ru (Ru/CoxP-MoP) featured porous morphology with interconnected channels. The specific nanostructure favors mass transport, such as electrolyte bubbles transfer and exposing rich active sites. Moreover, the coupling effects between metallic elements, especially the decorated Ru, also act as a pivotal role on enhancing the electrocatalytic performance. Benefiting from the effects of composition and specific nanostructure, the prepared Ru/CoxP-MoP exhibits efficient HER performance with a current density of 10 mA cm-2 achieved in 1 m KOH, 0.5 m H2SO4, seawater containing 1 m KOH and 1 m PBS, with overpotentials of 52, 59, 55, 90 mV, and coupling with good stability. This work opens a novel and fast avenue to design metal-phosphide-based nanomaterials in energy-conversion and storage fields.
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  • 文章类型: Journal Article
    设计并研究了一种新型的FePt/PPy-C复合纳米材料作为甲醇氧化反应(MOR)电催化剂。通过共还原法制备平均直径约为3nm的FePt纳米颗粒,然后将其负载到PPy-C复合载体上。电催化性能受FePt纳米颗粒的组成影响。实验结果表明,Fe1.5Pt1/PPy-C催化剂对MOR具有良好的催化活性和稳定性,质量活性和比活性分别为1.76AmgPt-1和2.71mAcm-2,比商业Pt/C催化剂高5.18和4.60倍。密度泛函理论(DFT)已被用来模拟催化剂载体的电结构。并进一步分析了甲醇氧化过程的机理。PPy-C界面的异质结可以加速电子从电催化中心向电极的迁移。有效地提高了甲醇氧化的可能性,DFT计算结果中的d带中心和FePt纳米粒子上的CO吸附能证实了这一点。
    A novel FePt/PPy-C composite nanomaterial has been designed and investigated as a methanol oxidation reaction (MOR) electrocatalyst. The FePt nanoparticles with an average diameter of about 3 nm have been prepared by the co-reduction method and then loaded onto the PPy-C composite support. The electrocatalytic performance is affected by the composition of the FePt nanoparticles. The experimental results indicated that the Fe1.5Pt1/PPy-C catalyst exhibited excellent catalytic activity and stability for MOR, with mass activity and specific activity of 1.76 A mgPt-1 and 2.71 mA cm-2, respectively, which are 5.18 and 4.60 times higher than that of the commercial Pt/C catalyst. Density functional theory (DFT) has been employed to simulate the electrical structures of catalyst supports, and the mechanism of the methanol oxidation process has been further analyzed. The heterojunctions of the PPy-C interface could accelerate the electron migration from the electrocatalytic center to the electrodes. The possibility of methanol oxidation has been improved effectively, which can be confirmed by the d-band center and CO adsorption energy on FePt nanoparticles in the DFT calculation results.
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  • 文章类型: Journal Article
    电催化二氧化碳还原反应(ECRR)有望将对环境有害的CO2转化为有用的化学物质,但该技术的大规模应用受到其低效率和选择性的严重限制。铜基电催化剂在将CO2转化为多种产品方面表现出诱人的能力,和产物选择性可以通过各种方法来操纵。其中,通过晶面工程暴露特定的晶面已被证明是非常有效的,在获得特定的产品,并吸引了众多的研究人员。然而,根据我们的知识,很少有报道系统地总结了Cu催化剂晶面控制与催化产物之间的关系。本文首先概述了Cu基催化剂上CO2电催化还原的一般机理,然后总结了低指数和高指数Cu方面对产品选择性的偏好,并深入研究了各方面之间的协同效应(包括不同的Cu方面以及Cu和非Cu方面之间的相互作用)及其对CO2还原反应的影响(CO2RR)。此外,还介绍了最近开发的Cu单原子催化剂在ECRR中的研究。最后,我们对高性能铜基催化剂在CO2RR中的应用进行了展望。这篇综述的目的是为以下关于Cu基电催化剂晶体面控制的研究提供清晰的脉络和有意义的指导。
    The electrocatalytic carbon dioxide reduction reaction (ECRR) is promising in converting environmentally harmful CO2 into useful chemicals, but the large-scale application of this technology is seriously limited by its low efficiency and selectivity. Cu-based electrocatalysts displayed attractive ability in converting CO2 to multiple products, and the product selectivity can be manipulated through various approaches. Among them, exposing specific crystal facets through crystal facet engineering has been proven to be highly effective in obtaining specific products and has attracted numerous researchers. However, to our knowledge, few reports have systematically summarized the relationship between the crystal facet control of Cu catalysts and the catalytic products. This review begins by outlining the general mechanism of CO2 electrocatalytic reduction on Cu-based catalysts, and then summarizes the preferences of low-index and high-index Cu facets regarding product selectivity and delves into the synergistic effects between facets (including different Cu facets and interactions between Cu and non-Cu facets) and their impact on CO2 reduction reaction (CO2RR). In addition, the study of the recently developed Cu single-atom catalysts in ECRR was also introduced. Finally, we provide an outlook on the development of high-performance Cu-based catalysts for applications in CO2RR. The purpose of this review is to provide a clear vein and meaningful guidance for the following studies over the crystal facet control of Cu-based electrocatalysts.
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  • 文章类型: Journal Article
    氧还原反应(ORR)是各种电化学储能装置的基础。基于原子水平的结构可调性,Fe/NC催化剂有望取代商业Pt/C作为氧电极催化剂。丰富的铁矿石储量和良好的活性。然而,缺乏耐久性和低活性位点密度阻碍了其发展。在这项工作中,耐用的催化剂,CuFe/NC,通过调节界面组成和电子结构来制备ORR。Cu纳米团簇的引入部分消除了Fe的Fenton效应,优化了FeNx的电子结构,从而有效地提高了长期耐久性和活性。制备的CuFe/NC表现出0.90V的半波电位(E1/2)和优异的稳定性,在10,000次循环后E1/2仅降低20mV。具有CuFe/NC的组装的碱性锌空气电池(ZAB)的开路电势为1.458V。在5mAcm-2的电流密度下,电池能够以稳定的极化运行600h。这种CuFe/NC可以促进新型和可再生的电化学能量存储装置的实际应用。
    Oxygen reduction reaction (ORR) serves as the foundation for various electrochemical energy storage devices. Fe/NC catalysts are expected to replace commercial Pt/C as oxygen electrode catalysts based on the structural tunability at the atomic level, abundant iron ore reserves and excellent activity. Nevertheless, the lack of durability and low active site density impede its advancement. In this work, a durable catalyst, CuFe/NC, for ORR was prepared by modulating the interfacial composition and electronic structure. The introduction of Cu nanoclusters partially eliminates the Fenton effect from Fe and optimizes the electron structure of FeNx, thereby effectively enhancing the long-term durability and activity. The prepared CuFe/NC exhibits a half-wave potential (E1/2) of 0.90 V and superior stability with a decrease in E1/2 of only 20 mV after 10,000 cycles. The assembled alkaline Zinc-Air batteries (ZABs) with CuFe/NC exhibit an open-circuit potential of 1.458 V. At a current density of 5 mA cm-2, the batteries are capable of operation for 600 h with a stable polarization. This CuFe/NC may promote the practical application of novel and renewable electrochemical energy storage devices.
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  • 文章类型: Journal Article
    由于碳载体在高电位的酸/碱溶液中的腐蚀,开发用于氧还原反应(ORR)的具有高活性和长期耐久性的碳负载的Pt基电催化剂对于它们的商业应用是巨大的挑战。在这项工作中,通过原位分子自组装策略合成了Janus结构TaON/石墨烯状碳(GLC),用作铂(Pt)的双载体。获得的Pt/TaON/GLC呈现高半波电位(0.94Vvs.RHE),在0.9V时具有出色的质量(1.48AmgPt-1)和比(1.75mAcmPt-2)活性,和卓越的长期耐久性,在碱性溶液中10,000次循环后质量活性损失最小(8.0%),优于Pt/C和其他催化剂。结构表征和密度泛函理论(DFT)计算表明,Pt/TaON/GLC催化剂表现出最大的协同作用,包括增强的界面电子密度,改进的电荷转移,增强O2吸附,并叠加OO卵裂。这项工作显示了通过协同促进的界面工程制备高活性和长期耐用的Pt基电催化剂的潜在策略。
    Developing carbon-supported Pt-based electrocatalysts with high activity and long-durability for the oxygen reduction reaction (ORR) is an enormous challenge for their commercial applications due to the corrosion of carbon supports in acid/alkaline solution at high potential. In this work, a Janus structural TaON/graphene-like carbon (GLC) was synthesized via an in-situ molecular selfassembly strategy, which was used as a dual-carrier for platinum (Pt). The as-obtained Pt/TaON/GLC presents high half-wave potential (0.94 V vs. RHE), excellent mass (1.48 A mgPt-1) and specific (1.75 mA cmPt-2) activities at 0.9 V, and superior long-term durability with a minimal loss (8.0 %) of mass activity after 10,000 cycles in alkaline solution, outperforming those of Pt/C and other catalysts. The structural characterizations and density functional theory (DFT) calculations indicate that the Pt/TaON/GLC catalyst exhibits the maximum synergies, including enhanced interfacial electron density, improved charge transfer, enhanced O2 adsorption, andsuperimposed OO cleavage. This work shows a potential strategy for preparing the high-active and long-durable Pt-based electrocatalyst by synergism-promoted interface engineering.
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  • 文章类型: Journal Article
    醛在铜基电催化剂上的氧化在一个小的电势窗口内可以在阳极产生氢,从而提供双极制氢系统。然而,Cu基醛氧化电催化剂的固有活性和稳定性在实际应用中仍不令人满意。在这里,通过在铜球上涂覆超薄碳壳,可以实现有效且稳定的甲醛氧化反应(FOR)以在非常低的电势下产生H2。FOR仅需要0.13V(vs.RHE)的电势即可达到100mAcm-2的电流密度。通过将FOR与析氢反应(HER)偶联,在阴极和阳极同时产生氢气。H2在双极状态下的法拉第效率接近100%。在流动池中,它需要0.1V的低电池电压才能达到100mAcm-2的电流密度。此外,它可以在高电流密度下稳定运行30小时以上。碳壳充当保护Cu(0)位点的装甲,避免铜的氧化,并在电解过程中长时间保持催化剂活性。实验和理论计算结果表明,电子转移发生在铜核和超薄碳壳之间的界面。超薄碳涂层Cu降低了反应能垒,使C-H键更容易断裂,并促进H偶联产生H2。该研究为设计具有长耐久性和活性的铜基电催化剂提供了基本原理。
    The oxidation of aldehydes on a copper-based electrocatalyst within a small potential window can produce hydrogen at the anode, thus offering a bipolar hydrogen production system. However, the inherent activity and stability of Cu-based electrocatalysts for aldehyde oxidation are still not satisfactory in practical application. Herein, by coating an ultrathin carbon shell on the copper sphere, an effective and stable formaldehyde oxidation reaction (FOR) can be realized to produce H2 at a very low potential. FOR needs only a potential of 0.13 V (vs RHE) to reach a current density of 100 mA cm-2. By coupling FOR with hydrogen evolution reaction (HER), hydrogen is generated simultaneously at both the cathode and the anode. The Faraday efficiency of H2 at the bipolar state is close to 100%. In a flow cell, it needs a low cell voltage of 0.1 V to reach a current density of 100 mA cm-2. Moreover, it can be operated steadily for more than 30 h at high current density. The carbon shell acts as an armor to protect the Cu(0) sites, avoid the oxidation of copper, and keep the catalyst activity for a long time in the electrolytic process. Experimental and theoretical calculation results indicate that electron transfer occurs at the interface between the copper core and ultrathin carbon shell. The ultrathin carbon-coated Cu reduces the reaction energy barrier, making the C-H bond more easily fractured and facilitating H coupling to generate H2. This study provides a basic principle for the design of copper-based electrocatalysts with long durability and activity.
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  • 文章类型: Journal Article
    NO3RR合成氨是一个复杂的八电子反应,涉及多个步骤和中间体,其中NO3-吸附和NH3解吸至关重要。Cu基高熵五元合金催化剂对硝酸还原为氨具有良好的表面吸附和解吸能力。这里,通过构建CuNiCoZnMn合金来协调催化位点,以调节催化位点的电子结构,以促进衬底的反应,从而优化整个反应路径。基于三元合金CuNiCo,Zn元素的引入继续降低解吸能垒,并且Mn元素的引入继续增强初始吸附能,从而可以快速保持和释放目标产物,以加速氨的产生。五元CuNiCoZnMn合金催化剂的NH3产率和法拉第效率达到723.7μmolh-1cm-2和96.6%,分别,在-0.35V与RHE电位。密度泛函理论计算表明,五元CuNiCoZnMn合金(NO3-至*NO3-)初始吸附自由能变化和(*NH3至NH3)NH3解吸自由能变化分别为-2.50,0.072eV,分别,显著优于-2.02、0.544eV和-1.97、0.217eV的三元CuNiC和四元CuNiCoZn。
    NO3RR synthesis of ammonia is a complex eight-electron reaction involving multiple steps and intermediates, in which NO3- adsorption and NH3 desorption are crucial. The Cu-based high entropy quinary alloy catalyst has good surface adsorption and desorption ability for the reduction of nitric acid to ammonia. Here, the catalytic sites were coordinated by constructing CuNiCoZnMn alloys to adjust the electronic structure of the catalytic sites to facilitate the reaction of the substrate and thus optimize the whole reaction path. Based on the ternary alloy CuNiCo, the introduction of the Zn element continues to reduce the desorption energy barrier, and the introduction of the Mn element continues to enhance the initial adsorption energy so that the target product can be quickly held and released to accelerate the production of ammonia. The NH3 yield and Faraday efficiency obtained for the quinary CuNiCoZnMn alloy catalyst reached 723.7 μmol h-1 cm-2 and 96.6%, respectively, at -0.35 V vs RHE potential. The density functional theory calculations showed that the quinary CuNiCoZnMn alloy (NO3- to *NO3-) initial adsorption-free energy change and (*NH3 to NH3) NH3 desorption-free energy change are -2.50, 0.072 eV, respectively, which are significantly better than those of the ternary CuNiC and quaternary CuNiCoZn of -2.02, 0.544 eV and -1.97, 0.217 eV.
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  • 文章类型: Journal Article
    在寻求通过水电解可持续制氢的过程中,高性能的发展,不含贵金属的催化体系是非常需要的。在这里,我们提出了一种创新的策略,通过微生物技术改善NiFeP合金的表面特性,并通过定制具有完整和互连的二维(2D)Co3O4的3D分层花状结构来富集活性位点。所得的3DCo3O4@NiFeP-5/24h具有由覆盖整个催化表面的交叉纳米颗粒组成的多孔结构。这种设计确保了全面的电解质离子渗透,并促进了气泡的释放,同时降低了气泡粘附率。值得注意的是,Co3O4@NiFeP-5/24h电极在碱性介质中表现出优异的析氢(HER)性能,其特点是高稳定性,低过电位(10mAcm-2的电流密度为106mV),和降低塔菲尔斜率(98mVdec-1)。此外,电极和电解质相之间最小的界面接触电阻强调了3DCo3O4@NiFeP-5/24h电极的高HER性能。本文采用的创新设计和制造策略具有推进水分解电催化领域的巨大潜力。为合理设计和开发无贵金属电催化剂提供了一条有前途的道路。
    In the quest for sustainable hydrogen production via water electrolysis, the development of high-performance, noble-metal-free catalytic systems is highly desired. Herein, we proposed an innovative strategy for the development of an electrocatalyst by refining the surface characteristics of a NiFeP alloy through microbiological techniques and subsequent enrichment of active sites by tailoring 3D hierarchical flower-like structures with intact and interconnected two-dimensional (2D) Co3O4. The resultant 3D Co3O4@NiFeP-5/24h has a porous structure comprised of intercrossed nanoparticles covering the entirety of the catalytic surface. This design ensures comprehensive electrolyte ion penetration and facilitates the release of gas bubbles while reducing bubble adhesion rates. Remarkably, the Co3O4@NiFeP-5/24h electrode demonstrates superior hydrogen evolution (HER) performance in an alkaline medium, characterized by its high stability, low overpotential (106 mV at a current density of 10 mA cm-2), and reduced Tafel slope (98 mV dec-1). Besides, the minimized interfacial contact resistance among the phases of electrode and electrolyte emphasizes the high HER performance of the 3D Co3O4@NiFeP-5/24h electrode. The innovative design and fabrication strategy employed herein holds significant potential for advancing the field of water-splitting electrocatalysis, offering a promising path toward the rational design and development of noble-metal-free electrocatalysts.
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  • 文章类型: Journal Article
    多元金属硫化物(MMSs)是电催化应用的高度合适的候选者,因为它们为优化电子结构和催化位点提供了许多参数。在这里,由嵌入S中的MMSs((NiCoCrMnFe)Sx)纳米颗粒组成的稳定纳米结构,由金属有机骨架(MOF)衍生并支撑在碳化木纤维(CWF)上的N-共掺杂碳(SNC)层是通过直接碳化制成的。受益于这种碳涂层配置,随着多元金属系统内的协同效应,(NiCoCrMnFe)Sx@SNC/CWF在1000mAcm-2的高电流密度下提供了260mV的异常低的超电势,48.5mVdec-1的小Tafel斜率和强大的电催化稳定性。此外,(NiCoCrMnFe)Sx@SNC/CWF用作可充电锌空气电池的阴极,显示出更高的功率密度和显着的耐久性,超过商业RuO2。因此,我们展示了采用高效耐用的MMSs材料进行低成本和可持续能源转换的可行性和优势。
    Multinary metal sulfides (MMSs) are highly suitable candidates for the application of electrocatalysis as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, a stable nanoarchitecture consisting of MMSs ((NiCoCrMnFe)Sx) nanoparticles embedded in S, N-codoped carbon (SNC) layers derived from metal organic framework (MOF) and supported on carbonized wood fibers (CWF) was fabricated by directly carbonization. Benefiting from this carbon-coated configuration, along with the synergistic effects within multinary metal systems, (NiCoCrMnFe)Sx@SNC/CWF delivers an exceptionally low overpotential of 260 mV at a high current density of 1000 mA cm-2, a small Tafel slope of 48.5 mV dec-1, and robust electrocatalytic stability. Furthermore, the (NiCoCrMnFe)Sx@SNC/CWF used as the cathode of rechargeable Zn-air batteries demonstrates higher power density and remarkable durability, surpassing that of commercial RuO2. Thus, we showcase the feasibility and advantages of employing highly efficient and durable MMSs materials for low-cost and sustainable energy conversion.
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  • 文章类型: Journal Article
    锡(Sn)基材料有望实现有效的CO2电还原为甲酸盐。在这里,我们通过在Cu掺杂的SnS2纳米片上沉积Cu来构建异质结。在电化学反应过程中,这种异质结演变为Cu2O@Cu6Sn5的高活性相,同时保持其二维形态。具体来说,在演变的异质结上实现了35mAcm-2的部分电流密度,甲酸盐生产的法拉第效率为93%。原位和非原位实验阐明了Cu2O@Cu6Sn5异质结的形成机理。Cu6Sn5纳米片是通过逐步脱硫工艺形成的,而Cu2O是通过与羟基自由基反应生成的。这种具有高电化学活性表面积的演化异质结协同稳定了*OCHO中间体,从而显著提高选择性和活性。我们的发现为结构演化过程提供了见解,并指导了用于CO2还原的选择性电催化剂的开发。
    Tin (Sn)-based materials are expected to realize efficient CO2 electroreduction into formate. Herein, we constructed a heterojunction by depositing Cu on Cu-doped SnS2 nanosheets. During the electrochemical reaction, this heterojunction evolves to a highly active phase of Cu2O@Cu6Sn5 while maintaining its two-dimensional morphology. Specifically, a partial current density of 35 mA cm-2 with an impressive faradaic efficiency of 93% for formate production was achieved over the evolved heterojunction. In situ and ex situ experiments elucidated the formation mechanism of the Cu2O@Cu6Sn5 heterojunction. Cu6Sn5 nanosheets were formed via a stepwise desulfurization process, while Cu2O was generated through its reaction with hydroxyl radicals. This evolved heterojunction with a high electrochemically active surface area synergistically stabilized the *OCHO intermediate, thereby significantly enhancing the selectivity and activity. Our findings provide insight into the structural evolution process and guide the development of selective electrocatalysts for CO2 reduction.
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