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随着工业发展和全球人口的持续增长,人类对化石燃料的消耗日益增加,从而导致大气中二氧化碳含量的显著增加以及与之相伴的一系列环境问题.电化学还原二氧化碳制备高附加值的燃料和化学品具有稳定的效率和较高的经济可行性等特点,目前已成为一种有前景的策略来缓解当前全球面临的能源短缺和气候变暖问题.然而,电催化二氧化碳还原过程存在反应能垒高和复杂的多电子/质子耦合过程等不足,因此,合理有效的电催化剂设计成为该领域的关键问题.近年,理解和明确电化学二氧化碳还原反应过程的活性起源、选择性调控机制和催化反应机理已成为高效电催化剂设计过程中的重要指导原则.作为一类独特的纳米尺度的金属氧簇,多金属氧酸盐(多酸)已成为二氧化碳还原领域的热点材料.尤其是,多酸明确的结构、优越的电子/质子存储转移能力和二氧化碳吸附活化能力有助于探究二氧化碳还原反应过程中的活性起源和构效机制.因此,利用多酸阐明电化学二氧化碳还原反应中的这些关键问题对于开发高效、可实用化的电催化剂意义重大.本文综述了近年多酸在电催化二氧化碳还原反应中取得的进展,重点介绍了多酸阴离子均相分子催化剂、多酸基无机-有机杂化材料催化剂、多酸电解质溶液、多酸-纳... 相似文献
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多金属氧酸盐电致变色材料 总被引:1,自引:0,他引:1
多金属氧酸盐具有多样的结构和良好的电化学可逆性,在电致变色器件(例如军事伪装、后视镜、智能窗以及高对比度信息显示器)上有着广阔的应用前景。本文综述了多金属氧酸盐在电致变色领域的研究进展情况。概述了多金属氧酸盐的电致变色机理以及制备多金属氧酸盐电致变色薄膜的方法,主要包括:溶胶-凝胶方法、电沉积法、Langmuir-Blodgett方法、层接层自组装方法。按照多金属氧酸盐的结构类型分类,结合最新文献报道,介绍了同多酸(盐)型和杂多酸(盐)型电致变色材料性能的研究现状。最后,对其未来的发展方向进行了展望。 相似文献
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钒取代多金属氧酸盐/聚酰胺-胺多层膜的制备及其电催化性能 总被引:1,自引:0,他引:1
用层接层自组装的方法制备了过渡金属钒取代的多金属氧酸盐PMo11VO4-40/聚酰胺-胺多层纳米复合膜. X射线光电子能谱(XPS)、紫外-可见光谱(UV-Vis)、循环伏安(CV)测定和分析结果表明, PMo11VO4-40和聚酰胺-胺通过静电相互作用形成了纳米交替多层膜,且膜的增长均匀. 复合膜的循环伏安图呈现出四对氧化还原峰(一个V的单电子和三个Mo的双电子), 峰电流与扫描速率成正比, 其式量电位随着pH 的增加而线性负移, 表明电极过程属于表面控制过程, 电荷传递很快且有氢离子参与多金属氧酸盐的氧化还原反应. 该方法制备的多层膜修饰电极稳定性好, 对NO-2、BrO-3及H2O2具有良好的催化还原活性. 相似文献
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电催化二氧化碳还原反应(E-CO2RR)可在温和条件下将CO2转化成高附加值燃料或化学品,近年来受到广泛关注,其在实际反应中涉及到气体扩散和多电子转移等复杂过程,构筑高效、稳定的催化电极是其发展的核心之一。然而,传统涂敷电极制备时,需要将催化剂与粘结剂混合涂覆于集流体表面,此过程会造成活性位点包埋和传质过程受限,致使催化剂活性位利用率下降,同时在反应过程中电极表面容易粉化,造成稳定性下降,难以重复利用。因此,如何调控电极反应界面,提升催化剂活性位的利用率仍面临挑战。将催化剂原位生长于集流体上得到的一体化电极可直接应用于电催化反应,不仅有利于提升活性位利用率以及电荷传输能力,还能有效调控三相界面处的微观反应环境(如pH、反应物及反应中间体的浓度等),从而实现电催化性能强化。本文综述了一体化电极用于E-CO2RR的最新进展,分析了结构和表界面调控对E-CO2RR性能的影响规律,并对该领域仍然存在的挑战和未来一体化E-CO2RR电极的发展进行了评述与展望。 相似文献
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近年来,随着温室效应即全球变暖引发的环境问题越来越严峻,因此,CO2转化与再生引起了科学界的广泛关注,其中备受关注的是电催化CO2还原。而二维材料电催化剂可以将CO2还原为高附加值的多碳化合物,但催化剂的合成设计以及理论研究有待更多的研究。从发现石墨烯开始,二维材料的其他超薄层状结构的广泛研究逐渐出现。本文重点综述了石墨烯、MXenes、金属氧化物、二维MOFs和过渡金属硫族化合物等二维材料的构建以及其CO2还原电催化技术应用方面的最新进展,并简要的介绍了二维材料的分类和制备方法。讨论了电催化CO2还原的基本原理以及反应途径。指出了二维材料电催化剂面临的机遇和挑战,旨在对二维材料电催化剂的合成以及应用提供一些新的思路。 相似文献
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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。 相似文献
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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.![]()
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Dharmendra Kumar Yadav Devesh Kumar Singh Vellaichamy Ganesan 《Current Opinion in Electrochemistry》2020
To decrease the global carbon footprint concerns and to diminish the energy crisis, electrocatalytic reduction of CO2 which results in the formulation of value-added chemicals is a potential solution. In this review, single-atom catalysts (SACs) which are rapidly growing and being developed as the stimulating catalytic materials for electrocatalytic reduction of CO2 with improved selectivity, efficiency, and stability are considered. Various factors which are responsible for the efficient CO2 reduction are discussed. The pyrolytic approach for the preparation of Ni-based SACs and the maximum atom utilization efficiency for the desirable production of CO from CO2 are highlighted. 相似文献
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Qiu-Jin Wu Dr. Duan-Hui Si Qiao Wu Yu-Liang Dong Prof. Rong Cao Prof. Yuan-Biao Huang 《Angewandte Chemie (International ed. in English)》2023,62(7):e202215687
We present the first example of charged imidazolium functionalized porphyrin-based covalent organic framework (Co-iBFBim-COF-X) for electrocatalytic CO2 reduction reaction, where the free anions (e.g., F−, Cl−, Br−, and I−) of imidazolium ions nearby the active Co sites can stabilize the key intermediate *COOH and inhibit hydrogen evolution reaction. Thus, Co-iBFBim-COF-X exhibits higher activity than the neutral Co-BFBim-COF, following the trend of F−<Cl−<Br−<I−. Particularly, the Co-iBFBim-COF-I− showed nearly 100 % CO2 selectivity at a low full-cell voltage of 2.3 V, and achieved a high CO2 partial current density of 52 mA cm−2 with a turnover frequency of 3018 h−1 at 2.4 V in the anion membrane electrode assembly, which is 3.57 times larger than that of neutral Co-BFBim-COF. This work provides new insight into the importance of free anions in the stabilization of intermediates and decreasing the local binding energy of H2O with active moiety to enhance CO2 reduction reaction. 相似文献
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Xinlin Li Sreehari Surendran Rajasree Dr. Venkatesh Gude Karan Maindan Prof. Dr. Pravas Deria 《Angewandte Chemie (International ed. in English)》2023,62(22):e202219046
Traditional MOF e-CRR, constructed from catalytic linkers, manifest a kinetic bottleneck during their multi-electron activation. Decoupling catalysis and charge transport can address such issues. Here, we build two MOF/e-CRR systems, CoPc@NU-1000 and TPP(Co)@NU-1000, by installing cobalt metalated phthalocyanine and tetraphenylporphyrin electrocatalysts within the redox active NU-1000 MOF. For CoPc@NU-1000, the e-CRR responsive CoI/0 potential is close to that of NU-1000 reduction compared to the TPP(Co)@NU-1000. Efficient charge delivery, defined by a higher diffusion (Dhop=4.1×10−12 cm2 s−1) and low charge-transport resistance ( =59.5 Ω) in CoPC@NU-1000 led FECO=80 %. In contrast, TPP(Co)@NU-1000 fared a poor FECO=24 % (Dhop=1.4×10−12 cm2 s−1 and =91.4 Ω). For such a decoupling strategy, careful choice of the host framework is critical in pairing up with the underlying electrochemical properties of the catalysts to facilitate the charge delivery for its activation. 相似文献
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Ning Ling Jiguang Zhang Meng Wang Zhen Wang Ziyu Mi Surani Bin Dolmanan Mingsheng Zhang Bingqing Wang Wan Ru Leow Jia Zhang Yanwei Lum 《Angewandte Chemie (International ed. in English)》2023,62(36):e202308782
Electrochemical CO2 reduction (CO2R) in acidic media with Cu-based catalysts tends to suffer from lowered selectivity towards multicarbon products. This could in principle be mitigated using tandem catalysis, whereby the *CO coverage on Cu is increased by introducing a CO generating catalyst (e.g. Ag) in close proximity. Although this has seen significant success in neutral/alkaline media, here we report that such a strategy becomes impeded in acidic electrolyte. This was investigated through the co-reduction of 13CO2/12CO mixtures using a series of Cu and CuAg catalysts. These experiments provide strong evidence for the occurrence of tandem catalysis in neutral media and its curtailment under acidic conditions. Density functional theory simulations suggest that the presence of H3O+ weakens the *CO binding energy of Cu, preventing effective utilization of tandem-supplied CO. Our findings also provide other unanticipated insights into the tandem catalysis reaction pathway and important design considerations for effective CO2R in acidic media. 相似文献
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Carbon dioxide (CO2) is regarded as a main contributor to the greenhouse effect. As a potential strategy to mitigate its negative impacts, the reduction of CO2 is environmentally critical, economically meaningful and scientifically challenging. Being both thermodynamically and kinetically unfavored, CO2 reduction requires catalysts as a crucial component irrespective of the reaction modes, be it electrocatalytic, photoelectrocatalytic or photocatalytic. In an effort to systematically review the types of catalysts that have been studied for CO2 reduction, we categorize them into two major groups: those being activated by external sources and those being photoexcited and activated themselves. Attention is focused on the detailed mechanisms for each group by which the reduction of CO2 proceeds, yielding a summary of the guiding principles for catalyst designs. This review highlights the importance of mechanistic studies, which permits us to discuss our perspectives on potential directions of catalyst investigation for future catalytic CO2 reduction research. 相似文献