负载型非晶态Cu/SiO2催化剂的非晶性质

以超细ＳｉＯ２为载体，用ＫＢＨ４还原Ｃｕ＾２＋盐溶液制备了非负载型Ｃｕ和负载型Ｃｕ／ＳｉＯ２催化剂，ＸＲＤ，ＴＥＭ和电子衍射分析结果表明，负载型Ｃｕ／ＳｉＯ２为完全非晶态，而非负载型Ｃｕ中存在着少量晶态Ｃｕ，ＤＳＣ结果表明，非晶态Ｃｕ／ＳｉＯ２的热稳定性明显高于非负载型Ｃｕ，说明超细ＳｉＯ２具有稳定非晶结构的作用，ＸＰＳ结果表明，还原产物中的铜原子呈Ｃｕ状态，ＩＣＰ分析结果表明，样品中的Ｂ含量均低     

负载型铜基超细催化剂的制备、表征和催化性能

超细粒子作为一种新型催化材料以其高活性和优良的选择性引起催化工作者的重视．超细粒子的制备方法有很多种，其中溶胶凝胶法是金属氧化物超细粒子制备的重要方法之一［１］．目前，关于负载型超细粒子的制备方法主要是溶胶凝胶超临界干燥，一类是由超细载体浸渍以活性组...     

Cu/SiO2催化剂结构对乙酸甲酯加氢性能的影响

采用尿素水解法制备了Cu/SiO₂催化剂, 探究其用于乙酸甲酯(MA)加氢制取乙醇的催化性能, 并通过N₂物理吸附、X射线衍射(XRD)、程序升温还原(TPR)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等表征方法分析了催化剂的物理化学特性, 探究了铜负载量和还原温度等对催化剂结构的影响, 以及与催化活性之间的关系. 发现在铜负载量分别为10%、20%和30% (质量分数, w)的催化剂中, 铜负载量为20%的催化剂因具有较多且分散均匀的活性组分而表现出最佳的加氢效果. 接着在铜负载量为20%的催化剂上研究了还原温度(270, 350, 450 ℃)对催化性能的影响, 发现在350 ℃下还原的催化剂活性最高, 在最佳的反应条件下, 乙酸甲酯转化率达到97.8%, 乙醇选择性达到64.9% (理论最大值为66.6%), 主要归属于它具有较高的铜物种分散度, 最合适的Cu⁰/(Cu⁰+Cu⁺)摩尔比例, 同时实现了解离氢气和活化乙酸甲酯的功能.     

ZrO2修饰Cu催化剂还原以及反应过程中表面组成的变化

通过热分解法制备Cu模型催化剂,然后经浸渍制备ZrO₂/Cu催化剂,采用SEM、XPS考察了催化剂表面形态和组成,并采用in-situ Raman考察了催化剂在还原和吸附CO和水的过程中随时间的变化。结果表明,还原前Cu催化剂表面主要存在CuO物种,而在ZrO₂/Cu表面,除了CuO物种,还存在着大量的表面羟基物种。ZrO₂/Cu相对Cu更加容易还原为Cu⁰,同时,ZrO₂在催化剂表面聚集形成絮状态,而Cu催化剂还原后主要形成Cu₂O物种。Cu催化剂表面吸附CO后,除了形成Cu-CO外,Cu₂O物种均会迅速消失形成CO₂。Cu催化剂对水的作用比较弱,但是ZrO₂/Cu催化剂和水作用较强,并且通过Cu-OH中间物形成Cu₂O物种。     

STUDY ON DETERMINATION OF TRACE Cu（Ⅱ） BY DDCT CHELATING RESIN PRECONCENTRATION AND THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

A new method for determination of Cu(Ⅱ) by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity (ε435 =3.6×105 L/mol· cm), which is 33 times higher than that of liquid phase spectrophotometry. It has a good selectivity (most coexisting ions could not influence determination) and an ideal precision [30μg Cu(Ⅱ), n=6, RSD= 1.67%]. The content of Cu(Ⅱ) in water, high purity rare earth and its oxide was determined. The detection limit of Cu(Ⅱ) is 5.3μg/L, and the linear range is 0～7.2 μg/ml. The result is satisfactory.     

ZrO2修饰Cu催化剂对甲醇吸附原位红外表征

通过原位红外漫反射实验比较研究了甲醇在Cu及ZrO2/Cu催化剂表面的吸附与反应,并且采用不同还原温度来处理催化剂,改变催化剂表面的氧含量,并进一步研究甲醇吸附和反应性能随着催化剂表面氧含量的变化规律.结果表明,甲醇在Cu催化剂表面反应生成吸附态甲醛物种,进一步生成CO2,而在ZrO2/Cu表面形成甲酸盐物种,并与表面氧进一步反应生成CO2.随着催化剂还原温度的升高,反应中间物进一步生成CO2的反应速率变慢,说明催化剂表面的氧物种含量决定着催化剂甲醇吸附中间物种的形成及反应速率.     

1，2－亚丙基双（草酰胺根）桥联的线性三核铜（Ⅱ）配合物的合成与磁性

本文合成和表征了四种新的三核铜（Ⅱ）配合物｛［Ｃｕ（Ｌ）］２［Ｃｕ（ＣＨ３－ｅｂｏ）］｝（ＣｌＯ４）２（ＣＨ３ｅｂｏ表示１，２－亚丙基双（草酰胺根），Ｌ表示１，１０－菲咯啉（ｐｈｅｎ）（１），５－硝基－１，１０－菲咯琳（ＮＯ２－ｐｈｅｍ）（２），２，２’－联吡啶（ｂｐｙ）（３）和４，４’－二甲基－２，２’－联吡啶（Ｍｅ２ｐｙ）（４））．测定了四种配合物的变温磁化率（７７－３００Ｋ），求得交换参数分别为Ｊ１＝－２１９．６ｃｍ－１，Ｊ２＝－１９１．７ｃｍ－１，Ｊ３＝－２００．８ｃｍ－１，Ｊ４＝－１８５．５ｃｍ－１，表明Ｃｕ（Ⅱ）－Ｃｕ（Ⅱ）离子间存在着强的反铁磁交换相互作用．     

稀土元素铒对Al-4Cu合金组织与性能的影响

采用拉伸力学性能测试、硬度测试、金相组织观察、透射电镜与能谱分析等方法, 研究了不同量稀土元素Er对Al-4Cu合金组织与性能的影响, 结果表明 稀土Er能够细化Al-4Cu合金的枝晶网胞组织;Er元素对Al-4Cu 合金的再结晶行为起到了抑止作用, 添加0.2% Er能使Al-4Cu合金的再结晶起始温度提高80 ℃左右, 再结晶终了温度提高50 ℃左右; 不同量稀土元素Er不能改善Al-4Cu合金的拉伸力学性能, 甚至在一定程度上使合金的力学性能降低, 这是因为添加到Al-4Cu合金中的Er元素并没有与Al作用形成细小的Al3Er颗粒, 而是与Al, Cu发生交互作用形成了低熔点共晶Al8Cu4Er相, 这使合金的力学性能在一定程度上有所降低.     

铜的表面氧在甲醇水蒸气重整反应中的作用

研究了Cu和ZrO₂/Cu模型催化剂的甲醇水蒸气重整制氢的反应性能, 结果表明, 纯铜催化剂的反应初始活性随着还原温度的增加而显著降低, 并且在失活后的催化剂反应体系中通入少量的氧, 可恢复催化剂的活性. 相对于Cu, ZrO₂/Cu催化剂的活性和稳定性显著增加. 催化剂的TPR, XPS以及原位FT-IR表征结果表明, 导致催化剂活性迅速降低的原因为催化剂表面氧物种的逐渐消耗. ZrO₂在反应过程中可以稳定铜表面氧以及Cu^＋物种, 从而显著提高了反应活性和稳定性.     

基于金属氧化物材料的二氧化碳电催化还原

The CO₂ level in the atmosphere has been increasing since the industrial revolution owing to anthropogenic activities. The increased CO₂ level has led to global warming and also has detrimental effects on human beings. Reducing the CO₂ level in the atmosphere is urgent for balancing the carbon cycle. In this regard, reduction in CO₂ emission and CO₂ storage and usage are the main strategies. Among these, CO₂ usage has been extensively explored, because it can reduce the CO₂ level and simultaneously provide opportunities for the development in catalysts and industries to convert CO₂ as a carbon source for preparing valuable products. However, transformation of CO₂ to other chemicals is challenging owing to its thermodynamic and kinetic stabilities. Among the CO₂ utilization techniques, electrochemical CO₂ reduction (ECR) is a promising alternative because it is generally conducted under ambient conditions, and water is used as the economical hydrogen source. Moreover, ECR offers a potential route to store electrical energy from renewable sources in the form of chemical energy, through generation of CO₂ reduction products. To improve the energy efficiency and viability of ECR, it is important to decrease the operational overpotential and maintain large current densities and high product selectivities; the development of efficient electrocatalysts is a critical aspect in this regard. To date, many kinds of materials have been designed and studied for application in ECR. Among these materials, metal oxide-based materials exhibit excellent performance as electrocatalysts for ECR and are attracting increasing attention in recent years. Investigation of the mechanism of reactions that involve metallic electrocatalysts has revealed the function of trace amount of oxidized metal species—it has been suggested that the presence of metal oxides and metal-oxygen bonds facilitates the activation of CO₂ and the subsequent formation and stabilization of the reaction intermediates, thereby resulting in high efficiency and selectivity of the ECR. Although the stability of metal oxides is a concern as they are prone to reduction under a cathodic potential, the catalytic performance of metal oxide-based catalysts can be maintained through careful designing of the morphology and structure of the materials. In addition, introducing other metal species to metal oxides and fabricating composites of metal oxides and other materials are effective strategies to achieve enhanced performance in ECR. In this review, we summarize the recent progress in the use of metal oxide-based materials as electrocatalysts and their application in ECR. The critical role, stability, and structure-performance relationship of the metal oxide-based materials for ECR are highlighted in the discussion. In the final part, we propose the future prospects for the development of metal oxide-based electrocatalysts for ECR.     

惰性小分子电催化还原反应的电解液调控

本文概述了惰性小分子电催化还原反应（如二氧化碳还原反应和氮气还原反应）中电解液的组成和作用机制,介绍了相关电解液研究的最新进展,并讨论了电解液调控在揭示反应机理、改善催化性能中的重要作用.     

CO2和N2电还原中缺陷及界面工程的最新进展

实现碳氮循环是人类社会发展的迫切要求,也是催化领域的热门研究课题。在可再生能源的推动下,电催化技术引起了人们的广泛关注,且可以通过改变反应电压获得不同的目标产品。基于此,电催化技术被认为是缓解当前能源危机和环境问题的有效策略,对实现碳中和具有重要意义。其中,电催化CO₂还原反应(CO₂RR)和N₂还原反应(N₂RR)是一种有前途的小分子转化策略。然而,CO₂和N₂均为线性分子,其中C＝O和N≡N键的高解离能导致了它们高的化学惰性。此外,最高占据分子轨道(HOMO)和最低未占分子轨道(LUMO)之间的巨大能量间隙使它们具有高的化学稳定性;且CO₂和N₂的低质子亲和力使它们难以被直接质子化。另一方面,由于CO₂RR和N₂RR与析氢反应(HER)具有相近的氧化还原电位,造成其与HER之间存在竞争性关系,这也是致使催化剂在CO₂RR和N₂RR转化效率低的重要影响因素。因此,CO₂RR和N₂RR仍然面临着过电位高及法拉第效率低等问题。为了克服这些瓶颈,人们为提升CO₂RR和N₂RR电催化剂性能做出了很多努力。众所周知,电催化过程发生在催化剂表面,主要涉及质量传递和电子转移等过程。由此可见,催化剂的性能与其质量和电子传输能力密切相关,而调控催化剂表面结构可以优化活性点的质量和电子转移行为。电催化剂的缺陷和界面工程可通过表面原子工程来实现电子结构调控,对于提高气体吸附能力、抑制HER、富集气体及稳定中间产物等具有重要意义。到目前为止,所报道的各种缺陷和复合电催化剂在提高CO₂RR和N₂RR催化性能等方面均表现出巨大的潜力。在此,我们综述了CO₂RR和N₂RR中催化剂缺陷工程及界面工程的最新进展;首先讨论了四种不同的缺陷(空位、高指数晶面、晶格应变和晶格无序)对CO₂RR和N₂RR性能的影响;然后,总结了界面工程在聚合物-无机复合材料催化剂中的重要作用,并给出了典型实例;最后,展望了原子级电催化剂工程的发展前景,提出了开发和设计高效CO₂RR和N₂RR电催化剂的未来发展方向。     

CeO2担载Cu纳米粒子电催化CO2还原产乙烯：CeO2不同暴露晶面对催化性能的影响

Fossil fuels are expected to be the major source of energy for the next few decades. However, combustion of nonrenewable resources leads to the release of large quantities of CO₂, the primary greenhouse gas. Notably, the concentration of CO₂ in the atmosphere is increasing annually at an astounding rate. Electrochemical CO₂ reduction (ECR) to value-added fuels and chemicals using electricity from intermittent renewable energy sources is a carbon-neutral method to alleviate anthropogenic CO₂ emissions. Despite the steady progress in the selective generation of C₁ products (CO and formic acid), the production of multi-carbon species still suffers from low selectivity and efficiency. As an ECR product, ethylene (C₂H₄) has a higher energy density than do C₁ species and is an important industrial feedstock in high demand. However, the conversion of CO₂ to C₂H₄ is plagued by low productivity and large overpotential, in addition to the severe competing hydrogen evolution reaction (HER) during the ECR. To address these issues, the design and development of advanced electrocatalysts are critical. Here, we demonstrate fine-tuning of ECR to C₂H₄ by taking advantage of the prominent interaction of Cu with shape-controlled CeO₂ nanocrystals, that is, cubes, rods, and octahedra predominantly covered with (100), (110), and (111) surfaces, respectively. We found that the selectivity and activity of the ECR depended strongly on the exposed crystal facets of CeO₂. The overall ECR Faradaic efficiency (FE) over Cu/CeO₂(110) (FE ≈ 56.7%) surpassed that of both Cu/CeO₂(100) (FE ≈ 51.5%) and Cu/CeO₂(111) (FE ≈ 48.4%) in 0.1 mol·L^-1 KHCO₃ solutions with an H-type cell. This was in stark contrast to the exclusive occurrence of the HER over pure carbon paper, CeO₂(100), CeO₂(110), and CeO₂(111). In particular, the FE toward C₂H₄ formation and the partial current density increased in the sequence Cu/CeO₂(111) < Cu/CeO₂(100) < Cu/CeO₂(110) within applied bias potentials from -1.00 to -1.15 V (vs. the reversible hydrogen electrode), reaching 39.1% over Cu/CeO₂(110) at a mild overpotential (1.13 V). The corresponding values for Cu/CeO₂(100) and Cu/CeO₂(111) were FE_C2H4 ≈ 31.8% and FE_C2H4 ≈ 29.6%, respectively. The C₂H₄ selectivity was comparable to that of many reported Cu-based electrocatalysts at similar overpotentials. Furthermore, the FE for C₂H₄ remained stable even after 6 h of continuous electrolysis. The superior ECR activity of Cu/CeO₂(110) to yield C₂H₄ was attributed to the metastable (110) surface, which not only promoted the effective adsorption of CO₂ but also remarkably stabilized Cu⁺, thereby boosting the ECR to produce C₂H₄. This work offers an alternative strategy to enhance the ECR efficiency by crystal facet engineering.     

铜基串联催化剂电催化CO2还原的研究进展

化石燃料的燃烧和其他人类活动排放了大量的CO₂气体,引发了诸多环境问题。电催化CO₂还原反应(CO₂RR)可以储存间歇可再生能源,实现人为闭合碳循环,被认为是获得高附加值化学品和燃料的有效途径。电催化CO₂RR涉及多个电子-质子转移步骤,其中^*CO通常被认为是关键中间体。铜由于对^*CO具有合适的吸附能,已被广泛证明是唯一能够有效地将CO₂还原为碳氢化合物和含氧化合物的金属催化剂。然而,纯Cu稳定性差、产品选择性低、过电位高,阻碍了工业级多碳产品的生产。构筑Cu基串联催化剂是提高CO₂RR性能的一种有前途的策略。本文首先介绍电催化CO₂RR的反应路线和串联机理。然后,系统地总结铜基串联催化剂对电催化CO₂RR的最新研究进展。最后,提出合理设计和可控合成新型电催化CO₂RR串联催化剂面临的挑战和机遇。     

铜基串联催化剂电催化CO2还原的研究进展

Through the combustion of fossil fuels and other human activities, large amounts of CO₂ gas have been emitted into the atmosphere, causing many environmental problems, such as the greenhouse effect and global warming. Thus, developing and utilizing renewable clean energy is crucial to reduce CO₂ emission and achieve carbon neutrality. The electrochemical CO₂ reduction reaction (CO₂RR) has been considered as an effective approach to obtain high value-added chemicals and fuels, which can store intermittent renewable energy and achieve the artificial carbon cycle. In addition, due to its multiple advantages, such as mild reaction conditions, tunable products, and simple implementation, electrochemical CO₂RR has attracted extensive attention. Electrochemical CO₂RR involves multiple electron–proton transfer steps to obtain multitudinous products, such as C₁ products (CO, HCOOH, CH₄, etc.) and C₂ products (C₂H₄, C₂H₅OH, etc.). The intermediates, among which ^*CO is usually identified as the key intermediate, and reaction pathways of different products intersect, resulting in an extremely complex reaction mechanism. Currently, copper has been widely proven to be the only metal catalyst that can efficiently reduce CO₂ to hydrocarbons and oxygenates due to its suitable adsorption energy for ^*CO. However, the low product selectivity, poor stability, and high overpotential of pure Cu hinder its use for the production of industrial-grade multi-carbon products. Tandem catalysts with multiple types of active sites can sequentially reduce CO₂ molecules into desired products. When loaded onto a co-catalyst that can efficiently convert CO₂ to ^*CO (such as Au and Ag), Cu acts as an electron donor owing to its high electrochemical potential. ^*CO species generated from the substrate can spillover onto the surface of electron-poor Cu due to the stronger adsorption and be further reduced to C₂₊ products. The use of Cu-based tandem catalysts for electrochemical CO₂RR is a promising strategy for improving the performance of CO₂RR and thus, has become a research hotspot in recent years. In this review, we first introduce the reaction routes and tandem mechanisms of electrochemical CO₂RR. Then, we systematically summarize the recent research progress of Cu-based tandem catalysts for electrochemical CO₂RR, including Cu-based metallic materials (alloys, heterojunction, and core-shell structures) as well as Cu-based framework materials, carbon materials, and polymer-modified materials. Importantly, the preparation methods of various Cu-based tandem catalysts and their structure–activity relationship in CO₂RR are discussed and analyzed in detail. Finally, the challenges and opportunities of the rational design and controllable synthesis of advanced tandem catalysts for electrochemical CO₂RR are proposed.     

还原氧化石墨烯@泡沫镍载CoO纳米花电极制备及催化CO2性能

本文以氧化石墨烯包覆泡沫镍电极(GO@NF)作为基底,采用水热法在GO@NF基底上原位生长CoO纳米花,同时GO在水热过程中被同步热还原为还原氧化石墨烯(RGO),从而一步制得还原氧化石墨烯包覆泡沫镍负载CoO纳米花电极(CoO/RGO@NF)。使用XRD和SEM对CoO/RGO@NF电极进行表征,发现CoO纳米花均匀生长在泡沫镍三维网络结构上,CoO纳米花为大量针状纳米棒围绕一个中心而成的花状结构,纳米棒的长度约为10 ~ 15 μm,直径约为100 ~ 200 nm。使用循环伏安和线性扫描法测试了CoO/RGO@NF电极电催化CO₂的还原性能,在-0.76 V（vs. SHE）电位下,CoO/RGO@NF电极电催化CO₂还原的电流效率达到70.9%,产甲酸法拉第效率达到65.2%,甲酸产率为59.8 μmol·h^-1·cm^-2,且电极可持续稳定电催化还原CO₂ 4 h,表明CoO/RGO@NF电极对CO₂电还原有着优良的催化活性、选择性和稳定性。     

Recent Progress on Bismuth-based Nanomaterials for Electrocatalytic Carbon Dioxide Reduction

Due to the burning of fossil fuels, the level of carbon dioxide(CO₂) in the atmosphere gradually rises, leading to serious greenhouse effect and environmental problems. Electrocatalytic reduction of CO₂ is currently an efficient way to convert CO₂ to value-added products. Bismuth(Bi)-based nanomaterials have raised great interests due to their excellent activity and high selectivity to electrocatalytic CO₂ reduction. In this review, the fundamental principles of electrochemical CO₂ reduction reaction(CO₂RR) are introduced at first. Moreover, the recent development of Bi-based electrocatalytic materials including Bi with various nanostructures(nanoparticle, nanosheet, etc.), Bi-based compounds(Bi oxide, bimetal chalcogenide, etc.), and Bi/C nanocomposites are summarized. In the end, the future prospects and challenges of electrocatalysts for CO₂ reduction are discussed.     

富氧空位的非晶氧化铜高选择性电催化还原CO2制乙烯（英文）

过量化石能源的消耗导致大气中的二氧化碳含量不断上升,由此引发包括温室效应在内的环境问题。对此,常温常压下的电催化二氧化碳还原手段为制备高附加值的化工原料和实现碳循环提供了一种很有前景的技术储备。在众多的二氧化碳还原产物中,碳氢化合物尤其是乙烯,它作为塑料和其他化工产品的重要原料受到广泛的关注。电催化二氧化碳还原制乙烯工艺不仅可适配于现有的生产设备也可作为取代目前工业化的裂解方法。近年来,研究者们为了开发高效的电催化二氧化碳还原制乙烯催化剂开展了大量的研究。不过值得注意的是,大部分研究集中于铜基材料。尽管目前研究者取得了很多成果,但仍缺少可高选择性产乙烯的二氧化碳还原催化剂。如何设计出可活化二氧化碳分子,同时对*CO和*COH中间物有强吸附能力的催化剂是研究难点。针对此问题,本文中通过真空蒸镀的方法制备出一种富氧空位的非晶氧化铜纳米薄膜催化剂。受益于纳米薄膜的构建和氧空位的引入,该催化剂可快速进行电荷和物质的交换,并利于二氧化碳分子的吸附及优化还原中间产物的亲和力,进而表现出优异的电催化二氧化碳制乙烯的性能。结果表明,在加有0.1 mol·L^-1碳酸氢钾溶液的H型电...     

面向CO2电化学转化的铜基催化剂研究进展

Burning of fossil fuels increases CO₂ concentration in the atmosphere, resulting in a series of climate- and environment-related concerns such as global warming, sea-level rise, and melting of glaciers. Therefore, utilization of renewable energy to reduce the CO₂ concentration, in order to realize a sustainable development, is urgent. Capturing and utilizing CO₂, a greenhouse gas, can not only address these concerns but also alleviate the current scenario of energy shortage. Thermal catalytic CO₂ hydrogenation offers various pathways with high conversion efficiencies to produce fuels and industrial chemicals including CO, HCOOH, CH₃OH, and CH₄. However, CO₂ is chemically inert due to the highly stable C＝O bond. Thus, harsh reaction conditions such as high temperature and pressure are required for CO₂ hydrogenation.