共查询到20条相似文献,搜索用时 0 毫秒
1.
Manish Kumar Dinker Meng-Meng Li Kan Zhao Mingrui Zuo Lifeng Ding Xiao-Qin Liu Lin-Bing Sun 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306495
Porous liquids (PLs), a summation of porous hosts and bulky solvents bestowing permanent cavities, are the prominent emerging materials. Despite great efforts, exploration of porous hosts and bulky solvents is still needed to develop new PL systems. Metal-organic polyhedra (MOPs) with discrete molecular architectures can be considered as porous hosts; however, many of them are insoluble entities. Here we report the transformation of type III PL to type II PLs by tuning the surface rigidity of insoluble MOP, Rh24L24, in a bulky ionic liquid (IL). Functionalization of N-donor molecules on Rh−Rh axial sites ensue their solubilization in bulky IL which confer type II PLs. Experimental and theoretical studies reveal the bulkiness of IL as per the cage apertures, and the cause of their dissolution as well. The obtained PLs, capturing more CO2 than neat solvent, have depicted higher catalytic activity for CO2 cycloaddition compared to individual MOPs and IL. 相似文献
2.
Yi Ning Xu Wenjing Li Huai Qin Fu Dr. Xin Yu Zhang Jia Yue Zhao Xuefeng Wu Dr. Hai Yang Yuan Prof. Minghui Zhu Prof. Sheng Dai Prof. Peng Fei Liu Prof. Hua Gui Yang 《Angewandte Chemie (International ed. in English)》2023,62(19):e202217296
The electrocatalytic reduction of carbon dioxide provides a feasibility to achieve a carbon-neutral energy cycle. However, there are a number of bottleneck issues to be resolved before industrial application, such as the low conversion efficiency, selectivity and reaction rate, etc. Engineering local environment is a critical way to address these challenges. Here, a monolayer MgAl-LDH was proposed to optimize the local environment of Cu for stimulating industrial-current-density CO2-to-C2H4 electroreduction in neutral media. In situ spectroscopic results and theoretical study demonstrated that the Cu electrode modified by MgAl-LDH (MgAl-LDH/Cu) displayed a much higher surface pH value compared to the bare Cu, which could be attributed to the decreased energy barrier for hydrolysis on MgAl-LDH sites with more OH− ions on the surface of the electrode. As a result, MgAl-LDH/Cu achieved a C2H4 Faradaic efficiency of 55.1 % at a current density up to 300 mA cm−2 in 1.0 M KHCO3 electrolyte. 相似文献
3.
Baoxin Ni Guiru Zhang Huiming Wang Yulin Min Kun Jiang Hexing Li 《Angewandte Chemie (International ed. in English)》2023,62(6):e202215574
The design for non-Cu-based catalysts with the function of producing C2+ products requires systematic knowledge of the intrinsic connection between the surface state as well as the catalytic activity and selectivity. In this work, photochemical in situ spectral surface characterization techniques combined with the first principle calculations (DFT) were applied to investigate the relationships between the composition of surface states, coordinated motifs, and catalytic selectivity of a titanium oxynitride catalyst. When the catalyst mediates CO2 photoreduction, C2 product selectivity is positively correlated with the surface Ti2+/Ti3+ ratio and the surface oxidation state is regulated and controlled by coordinated motifs of N−Ti-O/V[O], which can reduce the potential dimerization energy barriers of *CO−CO* and promote spontaneous formation of the subsequent *CO−CH2* intermediate. This phenomenon provides a new perspective for the design of heterogeneous catalysts for photoreduction of CO2 into useful products. 相似文献
4.
Shuanglin He Yuhang Qing Ping Zhang Ying Xiong Qianqian Wu Yaping Zhang Lin Chen Fang Huang Fei Li 《Angewandte Chemie (International ed. in English)》2023,62(20):e202216082
A series of manganese polypyridine complexes were prepared as CO2 reduction electrocatalysts. Among these catalysts, the intramolecular proton tunneling distance for metal hydride formation (PTD-MH) vary from 2.400 to 2.696 Å while the structural, energetic, and electronic factors remain essentially similar to each other. The experimental and theoretical results revealed that the selectivity of CO2 reduction reaction (CO2RR) is dominated by the intramolecular PTD-MH within a difference of ca. 0.3 Å. Specifically, the catalyst functionalized with a pendent phenol group featuring a slightly longer PTD-MH favors the binding of proton to the [Mn−CO2] adduct rather than the Mn center and results in ca. 100 % selectivity for CO product. In contrast, decreasing the PTD-MH by attaching a dangling tertiary amine in the same catalyst skeleton facilitates the proton binding on the Mn center and switches the product from CO to HCOOH with a selectivity of 86 %. 相似文献
5.
Shang Li Yuxing Xu Dr. Hengwei Wang Prof. Botao Teng Dr. Qin Liu Dr. Qiuhua Li Lulu Xu Xinyu Liu Prof. Junling Lu 《Angewandte Chemie (International ed. in English)》2023,62(8):e202218167
Tuning the coordination environments of metal single atoms (M1) in single-atom catalysts has shown large impacts on catalytic activity and stability but often barely on selectivity in thermocatalysis. Here, we report that simultaneously regulating both Rh1 atoms and ZrO2 support with alkali ions (e.g., Na) enables efficient switching of the reaction products from nearly 100 % CH4 to above 99 % CO in CO2 hydrogenation in a wide temperature range (240–440 °C) along with a record high activity of 9.4 molCO gRh−1 h−1 at 300 °C and long-term stability. In situ spectroscopic characterization and theoretical calculations unveil that alkali ions on ZrO2 change the surface intermediate from formate to carboxy species during CO2 activation, thus leading to exclusive CO formation. Meanwhile, alkali ions also reinforce the electronic Rh1-support interactions, endowing the Rh1 atoms more electron deficient, which improves the stability against sintering and inhibits deep hydrogenation of CO to CH4. 相似文献
6.
Ting Deng Shuaiqiang Jia Chunjun Chen Jiapeng Jiao Xiao Chen Cheng Xue Wei Xia Dr. Xueqing Xing Dr. Qinggong Zhu Prof. Dr. Haihong Wu Prof. Dr. Mingyuan He Prof. Dr. Buxing Han 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202313796
Modulation of the microenvironment on the electrode surface is one of the effective means to improve the efficiency of electrocatalytic carbon dioxide reduction (eCO2RR). To achieve high conversion rates, the phase boundary at the electrode surface should be finely controlled to overcome the limitation of CO2 solubility in the aqueous electrolyte. Herein, we developed a simple and efficient method to structure electrocatalyst with a superhydrophobic surface microenvironment by one-step co-electrodeposition of Cu and polytetrafluoroethylene (PTFE) on carbon paper. The super-hydrophobic Cu-based electrode displayed a high ethylene (C2H4) selectivity with a Faraday efficiency (FE) of 67.3 % at −1.25 V vs. reversible hydrogen electrode (RHE) in an H-type cell, which is 2.5 times higher than a regular Cu electrode without PTFE. By using PTFE as a surface modifier, the activity of eCO2RR is enhanced and water (proton) adsorption is inhibited. This strategy has the potential to be applied to other gas-conversion electrocatalysts. 相似文献
7.
Z Zhang WY Gao L Wojtas S Ma M Eddaoudi MJ Zaworotko 《Angewandte Chemie (International ed. in English)》2012,51(37):9330-9334
Keeping MOM: Reaction of biphenyl-3,4',5-tricarboxylate and Cd(NO(3) )(2) in the presence of meso-tetra(N-methyl-4-pyridyl)porphine tetratosylate afforded porph@MOM-11, a microporous metal-organic material (MOM) that encapsulates cationic porphyrins and solvent in alternating open channels. Porph@MOM-11 has cation and anion binding sites that facilitate cooperative addition of inorganic salts (such as M(+) Cl(-) ) in a stoichiometric fashion. 相似文献
8.
《Analytical letters》2012,45(4):743-749
Abstract The effect of cyclohexanol added to the micellar solution of sodium dodecyl sulfate in the micellar electrokinetic chromatography of several aromatic compounds was investigated. Cyclohexanol (0.05–-0.10 M) diminished the capacity factors (k') of the solutes possessing hydrophilic functional groups which were solubilized near the micellar surface, whereas little changed the k' of the hydrophobic solutes solubilized in the micellar core. This selective effect was ascribed to the saturation of the micellar surface with cyclohexanol. 相似文献
9.
Qiuyue Ge Yangyang Liu Kejian Li Lifang Xie Xuejun Ruan Wei Wang Longqian Wang Tao Wang Wenbo You Liwu Zhang 《Angewandte Chemie (International ed. in English)》2023,62(27):e202304189
Solar-driven CO2 reduction reaction (CO2RR) is largely constrained by the sluggish mass transfer and fast combination of photogenerated charge carriers. Herein, we find that the photocatalytic CO2RR efficiency at the abundant gas-liquid interface provided by microdroplets is two orders of magnitude higher than that of the corresponding bulk phase reaction. Even in the absence of sacrificial agents, the production rates of HCOOH over WO3 ⋅ 0.33H2O mediated by microdroplets reaches 2536 μmol h−1 g−1 (vs. 13 μmol h−1 g−1 in bulk phase), which is significantly superior to the previously reported photocatalytic CO2RR in bulk phase reaction condition. Beyond the efficient delivery of CO2 to photocatalyst surfaces within microdroplets, we reveal that the strong electric field at the gas-liquid interface of microdroplets essentially promotes the separation of photogenerated electron-hole pairs. This study provides a deep understanding of ultrafast reaction kinetics promoted by the gas-liquid interface of microdroplets and a novel way of addressing the low efficiency of photocatalytic CO2 reduction to fuel. 相似文献
10.
Gina R. Wilson Kyoung Chul Park Grace C. Thaggard Dr. Corey R. Martin Austin R. Hill Johanna Haimerl Dr. Jaewoong Lim Buddhima K. P. Maldeni Kankanamalage Brandon J. Yarbrough Kelly L. Forrester Prof. Dr. Roland A. Fischer Dr. Perry J. Pellechia Dr. Mark D. Smith Prof. Dr. Sophya Garashchuk Prof. Dr. Natalia B. Shustova 《Angewandte Chemie (International ed. in English)》2023,62(37):e202308715
Cooperative behavior and orthogonal responses of two classes of coordinatively integrated photochromic molecules towards distinct external stimuli were demonstrated on the first example of a photo-thermo-responsive hierarchical platform. Synergetic and orthogonal responses to temperature and excitation wavelength are achieved by confining the stimuli-responsive moieties within a metal–organic framework (MOF), leading to the preparation of a novel photo-thermo-responsive spiropyran-diarylethene based material. Synergistic behavior of two photoswitches enables the study of stimuli-responsive resonance energy transfer as well as control of the photoinduced charge transfer processes, milestones required to advance optoelectronics development. Spectroscopic studies in combination with theoretical modeling revealed a nonlinear effect on the material electronic structure arising from the coordinative integration of photoresponsive molecules with distinct photoisomerization mechanisms. Thus, the reported work covers multivariable facets of not only fundamental aspects of photoswitch cooperativity, but also provides a pathway to modulate photophysics and electronics of multidimensional functional materials exhibiting thermo-photochromism. 相似文献
11.
Min Wang Huimin Chen Min Wang Jinxiu Wang Dr. Yongxiao Tuo Prof. Wenzhen Li Shanshan Zhou Linghui Kong Prof. Guangbo Liu Prof. Luhua Jiang Guoxiong Wang 《Angewandte Chemie (International ed. in English)》2023,62(40):e202306456
Heterostructured oxides with versatile active sites, as a class of efficient catalysts for CO2 electrochemical reduction (CO2ER), are prone to undergo structure reconstruction under working conditions, thus bringing challenges to understanding the reaction mechanism and rationally designing catalysts. Herein, we for the first time elucidate the structural reconstruction of CuO/SnO2 under electrochemical potentials and reveal the intrinsic relationship between CO2ER product selectivity and the in situ evolved heterostructures. At −0.85 VRHE, the CuO/SnO2 evolves to Cu2O/SnO2 with high selectivity to HCOOH (Faradaic efficiency of 54.81 %). Mostly interestingly, it is reconstructed to Cu/SnO2-x at −1.05 VRHE with significantly improved Faradaic efficiency to ethanol of 39.8 %. In situ Raman spectra and density functional theory (DFT) calculations reveal that the synergetic absorption of *COOH and *CHOCO intermediates at the interface of Cu/SnO2-x favors the formation of *CO and decreases the energy barrier of C−C coupling, leading to high selectivity to ethanol. 相似文献
12.
《Analytical letters》2012,45(15):1241-1253
Abstract A three-electrode system with the hanging electrolyte drop electrode (HEDE) was developed for the analytical exploitation of electrolysis at the interface between two immiscible electrolyte solutions (ITIES). The use of the differential pulse stripping voltammetry (DPSV) for the quantitative determination of the species which participates in a charge transfer reaction at ITIES was demonstrated with acetylcholine cation transfer across the water/nitrobenzene interface. Trace concentration of acetylcholine in water in the part per million level (ppm) can be determined. It was concluded that the electrolysis at ITIES represents the perspective method of chemical analysis. 相似文献
13.
与其他的锂电池体系相比,锂-空气电池具有最高的理论比能量,被认为有潜力成为终极能量转换和储存装置。目前的锂-空气电池常常使用气体钢瓶提供纯氧气,而非空气中的氧气,这种电池设计极大降低了锂-空气电池的能量密度和实用性。然而,当空气作为锂-空气电池的氧气供给源时,二氧化碳作为杂质会引起严重的副反应,从而降低锂-空气电池的性能。要解决二氧化碳引起的副反应,理解其反应机制至关重要。本文综述了锂-空气电池中有关二氧化碳诱发的化学/电化学反应的研究进展; 总结了可缓解二氧化碳负面效应的有效策略。此外,对二氧化碳选透膜材料和分离技术用于锂-空气电池进行了展望。 相似文献
14.
Meng-Di Zhang Jia-Run Huang Dr. Wen Shi Prof. Pei-Qin Liao Prof. Xiao-Ming Chen 《Angewandte Chemie (International ed. in English)》2023,62(42):e202308195
Solvent effect plays an important role in catalytic reaction, but there is little research and attention on it in electrochemical CO2 reduction reaction (eCO2RR). Herein, we report a stable covalent-organic framework (denoted as PcNi-im ) with imidazole groups as a new electrocatalyst for eCO2RR to CO. Interestingly, compared with neutral conditions, PcNi-im not only showed high Faraday efficiency of CO product (≈100 %) under acidic conditions (pH ≈ 1), but also the partial current density was increased from 258 to 320 mA cm−2. No obvious degradation was observed over 10 hours of continuous operation at the current density of 250 mA cm−2. The mechanism study shows that the imidazole group on the framework can be protonated to form an imidazole cation in acidic media, hence reducing the surface work function and charge density of the active metal center. As a result, CO poisoning effect is weakened and the key intermediate *COOH is also stabilized, thus accelerating the catalytic reaction rate. 相似文献
15.
人工光合作用可直接将二氧化碳转化为一系列碳氢化合物,实现大气中的碳循环,被视为一种既能解决能源短缺又能减少温室气体,进而改善人类生存环境的新型绿色技术.光催化二氧化碳还原体系需要合适的耦合氧化还原反应,以及对外界光源的有效利用以产生足够电子参与反应,因此构建高催化活性和高选择性的催化体系仍然面临着巨大挑战.此外,二维纳米结构(2D)由于具有比表面积大、离子的迁移路径短以及独特的平层电子转移轨道等特性,被证实有利于光催化还原CO2过程.其中,Bi3NbO7特殊的片层结构和合适的能带位置,使其在光催化还原CO2反应中表现出良好的催化性能.然而,Bi3NbO7的光生载流子易复合及反应中光腐蚀严重等缺陷导致其光利用率较低,限制了其实际应用.因此,构建S-型异质结是提高复合材料光催化活性的一种有前途的策略.S-型异质结不仅能有效地分离光生电子和空穴,而且这一电子转移过程赋予了复合物最大的氧化还原能力.同时,S-型光催化体系不仅拥有同样的强氧化和强还原能力,还可显著抑制副反应的发生及副产物的产生,有利于CO2还原反应的高选择性进行.本文利用简易的溶剂热法制备了一系列S-型Bi3NbO7/g-C3N4(BNO/UCN)异质结光催化剂,与其纯组分催化剂相比,表现出优异的光催化还原CO2活性,g-C3N4含量为80wt%的BNO/UCN-3光催化剂催化CO2生成CH4产率为37.59μmol·g-1h-1,是g-C3N4的15倍,CH4选择性为90%;且循环反应10次后仍保持较高的活性及CH4选择性.光催化活性及选择性的显著增强是由于二维分布的纳米结构和S-型电荷转移路径.在可见光照射下,界面内建电场、带边缘弯曲和库仑相互作用协同促进了复合物相对无用的电子和空穴的复合.因此,剩余的电子和空穴具有较高的还原性和氧化性,使复合材料具有较高的氧化还原能力.自由基捕获实验、电子顺磁共振实验和原位X射线光电子能谱实验结果表明,光催化剂中的电子迁移遵循S-型异质结机理.综上,本文不仅为新型S-型异质结CO2还原光催化剂的设计和制备提供了新方法,而且为未来解决能源短缺及实现碳中和目标提供一定的实验及理论依据. 相似文献
16.
Qihao Wang Chao Yang Yaqin Yan Haisheng Yu Anxiang Guan Dr. Miao Kan Dr. Quan Zhang Prof. Linjuan Zhang Prof. Gengfeng Zheng 《Angewandte Chemie (International ed. in English)》2023,62(5):e202212733
The electrocatalytic carbon dioxide (CO2) reduction is a promising approach for converting this greenhouse gas into value-added chemicals, while the capability of producing products with longer carbon chains (Cn>3) is limited. Herein, we demonstrate the Br-assisted electrocatalytic oxidation of ethylene (C2H4), a major CO2 electroreduction product, into 2-bromoethanol by electro-generated bromine on metal phthalocyanine catalysts. Due to the preferential formation of Br2 over *O or Cl2 to activate the C=C bond, a high partial current density of producing 2-bromoethanol (46.6 mA⋅cm−2) was obtained with 87.2 % Faradaic efficiency. Further coupling with the electrocatalytic nitrite reduction to ammonia at the cathode allowed the production of triethanolamine with six carbon atoms. Moreover, by coupling a CO2 electrolysis cell for in situ C2H4 generation and a C2H4 oxidation/nitrite reduction cell, the capability of upgrading of CO2 and nitrite into triethanolamine was demonstrated. 相似文献
17.
利用红外光谱、程序升温脱附、程序升温表面反应和激光表面反应技术研究了固体NiSO_4表面上CO、H_2和C_2H_4的化学吸附性能及激光促进CO加氢合成乙烯的反应机理。实验结果表明:在硫酸镍固体表面上卧式吸附于S-O-Ni键S位和Ni位的CO是激光合成乙烯的有效吸附态;解离吸附于硫氧双键氧位上的H参与CO加氢反应;激光选择激发表面S-O键,通过能量传递和驰豫使卧式吸附态C=O键活化并与吸附态H反应生成CH_2物种和H_2O,继而邻近的CH_2结合形成产物C_2H_4。 相似文献
18.
Yangyang Zhang Yanxu Chen Xiaowen Wang Yafei Feng Huaikun Zhang Prof. Genqiang Zhang 《Angewandte Chemie (International ed. in English)》2023,62(26):e202302241
Electrochemical conversion of CO2 to highly valuable ethanol has been considered a intriguring strategy for carbon neutruality. However, the slow kinetics of coupling carbon-carbon (C−C) bonds, especially the low selectivity ethanol than ethylene in neutral conditions, is a significant challenge. Herein, the asymmetrical refinement structure with enhanced charge polarization is built in the vertically oriented bimetallic organic frameworks (NiCu-MOF) nanorod array with encapsulated Cu2O (Cu2O@MOF/CF), which can induce an intensive internal electric field to increase the C−C coupling for producing ethanol in neutral electrolyte. Particularly, when directly employed Cu2O@MOF/CF as the self-supporting electrode, the ethanol faradaic efficiency (FEethanol) could reach maximum 44.3 % with an energy efficiency of 27 % at a low working-potential of −0.615 V versus the reversible hydrogen electrode (vs. RHE) using CO2-saturated 0.5 M KHCO3 as the electrolyte. Experimental and theoretical studies suggest that the polarization of atomically localized electric fields derived from the asymmetric electron distribution can tune the moderate adsorption of *CO to assist the C−C coupling and reduce the formation energy of H2CCHO*-to-*OCHCH3 for the generation of ethanol. Our research offers a reference for the design of highly active and selective electrocatalysts for reducing CO2 to multicarbon chemicals. 相似文献
19.
Ling-Ya Peng Guang-Ning Pan Wen-Kai Chen Xiang-Yang Liu Wei-Hai Fang Ganglong Cui 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(5):e202315300
Photocatalytic CO2 reduction is one of the best solutions to solve the global energy crisis and to realize carbon neutralization. The tetradentate phosphine-bipyridine (bpy)-phosphine (PNNP)-type Ir(III) photocatalyst, Mes-IrPCY2, was reported with a high HCOOH selectivity but the photocatalytic mechanism remains elusive. Herein, we employ electronic structure methods in combination with radiative, nonradiative, and electron transfer rate calculations, to explore the entire photocatalytic cycle to either HCOOH or CO, based on which a new mechanistic scenario is proposed. The catalytic reduction reaction starts from the generation of the precursor metal-to-ligand charge transfer (3MLCT) state. Subsequently, the divergence happens from the 3MLCT state, the single electron transfer (SET) and deprotonation process lead to the formation of one-electron-reduced species and Ir(I) species, which initiate the reduction reaction to HCOOH and CO, respectively. Interestingly, the efficient occurrence of proton or electron transfer reduces barriers of critical steps. In addition, nonadiabatic transitions play a nonnegligible role in the cycle. We suggest a lower free-energy barrier in the reaction-limiting step and the very efficient SET in 3MLCT are cooperatively responsible for a high HCOOH selectivity. The gained mechanistic insights could help chemists to understand, regulate, and design photocatalytic CO2 reduction reaction of similar function-integrated molecular photocatalyst. 相似文献
20.
Dr. Abebe R. Woldu Pooya Talebi Asfaw G. Yohannes Jianyin Xu Xu-Dong Wu Dr. Samira Siahrostami Dr. Liangsheng Hu Prof. Xiao-Chun Huang 《Angewandte Chemie (International ed. in English)》2023,62(29):e202301621
Tin disulfide (SnS2) is a promising candidate for electrosynthesis of CO2-to-formate while the low activity and selectivity remain a great challenge. Herein, we report the potentiostatic and pulsed potential CO2RR performance of SnS2 nanosheets (NSs) with tunable S-vacancy and exposure of Sn-atoms or S-atoms prepared controllably by calcination of SnS2 at different temperatures under the H2/Ar atmosphere. The catalytic activity of S-vacancy SnS2 (Vs-SnS2) is improved 1.8 times, but it exhibits an exclusive hydrogen evolution with about 100 % FE under all potentials investigated in the static conditions. The theoretical calculations reveal that the adsorption of *H on the Vs-SnS2 surface is energetically more favorable than the carbonaceous intermediates, resulting in active site coverage that hinders the carbon intermediates from being adsorbed. Fortunately, the main product can be switched from hydrogen to formate by applying pulsed potential electrolysis benefiting from in situ formed partially oxidized SnS2−x with the oxide phase selective to formate and the S-vacancy to hydrogen. This work highlights not only the Vs-SnS2 NSs lead to exclusively H2 formation, but also provides insights into the systematic design of highly selective CO2 reduction catalysts reconstructed by pulsed potential electrolysis. 相似文献