共查询到20条相似文献,搜索用时 15 毫秒
1.
Yucheng Cao Suya Chen Shuowen Bo Dr. Wenjun Fan Jiangnan Li Dr. Chunmei Jia Prof. Dr. Zhen Zhou Prof. Dr. Qinghua Liu Dr. Lirong Zheng Prof. Dr. Fuxiang Zhang 《Angewandte Chemie (International ed. in English)》2023,62(30):e202303048
Single atom alloy (SAA) catalysts have been recently explored for promotion of various heterogeneous catalysis, but it remains unexplored for selective electrocatalytic reduction of carbon dioxide (CO2) into multi-carbon (C2+) products involving C−C coupling. Herein we report a single-atomic Bi decorated Cu alloy (denoted as BiCu-SAA) electrocatalyst that could effectively modulate selectivity of CO2 reduction into C2+ products instead of previous C1 ones. The BiCu-SAA catalyst exhibits remarkably superior selectivity of C2+ products with optimal Faradaic efficiency (FE) of 73.4 % compared to the pure copper nanoparticle or Bi nanoparticles-decorated Cu nanocomposites, and its structure and performance can be well maintained at current density of 400 mA cm−2 under the flow cell system. Based on our in situ characterizations and density functional theory calculations, the BiCu-SAA is found to favor the activation of CO2 and subsequent C−C coupling during the electrocatalytic reaction, as should be responsible for its extraordinary C2+ selectivity. 相似文献
2.
Dr. Chuwei Zhu Wenlong Xu Fang Liu Dr. Jie Luo Prof. Junling Lu Prof. Wei-Xue Li 《Angewandte Chemie (International ed. in English)》2023,62(23):e202300110
Increasing selectivity without the expense of activity is desired but challenging in heterogeneous catalysis. By revealing the molecule saturation and adsorption sensitivity on overlayer thickness, strain, and coordination of Pd-based catalysts from first-principles calculations, we designed a stable Pd monolayer (ML) catalyst on a Ru terrace to boost both activity and selectivity of acetylene semihydrogenation. The least saturated molecule is most sensitive to the change in catalyst electronic and geometric properties. By simultaneously compressing the Pd ML and exposing the high coordination sites, the adsorption of more saturated ethylene is considerably weakened to facilitate the desorption for high selectivity. The even stronger weakening to the least saturated acetylene drives its hydrogenation such that it is more exothermic, thereby boosting the activity. Tailoring the molecule saturation and its sensitivity to structure and composition provides a tool for rational design of efficient catalysts. 相似文献
3.
Xin Zi Yajiao Zhou Li Zhu Qin Chen Yao Tan Xiqing Wang Dr. Mahmoud Sayed Dr. Evangelina Pensa Dr. Ramadan A. Geioushy Dr. Kang Liu Dr. Junwei Fu Prof. Emiliano Cortés Prof. Min Liu 《Angewandte Chemie (International ed. in English)》2023,62(42):e202309351
Electrocatalytic CO2 reduction reaction (CO2RR) to multi-carbon products (C2+) in acidic electrolyte is one of the most advanced routes for tackling our current climate and energy crisis. However, the competing hydrogen evolution reaction (HER) and the poor selectivity towards the valuable C2+ products are the major obstacles for the upscaling of these technologies. High local potassium ions (K+) concentration at the cathode's surface can inhibit proton-diffusion and accelerate the desirable carbon-carbon (C−C) coupling process. However, the solubility limit of potassium salts in bulk solution constrains the maximum achievable K+ concentration at the reaction sites and thus the overall acidic CO2RR performance of most electrocatalysts. In this work, we demonstrate that Cu nanoneedles induce ultrahigh local K+ concentrations (4.22 M) – thus breaking the K+ solubility limit (3.5 M) – which enables a highly efficient CO2RR in 3 M KCl at pH=1. As a result, a Faradaic efficiency of 90.69±2.15 % for C2+ (FEC2+) can be achieved at 1400 mA.cm−2, simultaneous with a single pass carbon efficiency (SPCE) of 25.49±0.82 % at a CO2 flow rate of 7 sccm. 相似文献
4.
Weibin Xu Han-Xuan Liu Yue Hu Zhen Wang Zheng-Qing Huang Chuande Huang Jian Lin Chun-Ran Chang Aiqin Wang Xiaodong Wang Tao Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(16):e202315343
Direct methane conversion (DMC) to oxygenates at low temperature is of great value but remains challenging due to the high energy barrier for C−H bond activation. Here, we report that in situ decoration of Pd1-ZSM-5 single atom catalyst (SAC) by CO molecules significantly promoted the DMC reaction, giving the highest turnover frequency of 207 h−1 ever reported at room temperature and ~100 % oxygenates selectivity with H2O2 as oxidant. Combined characterizations and DFT calculations illustrate that the C-atom of CO prefers to coordinate with Pd1, which donates electrons to the Pd1−O active center (L−Pd1−O, L=CO) generated by H2O2 oxidation. The correspondingly improved electron density over Pd−O pair renders a favorable heterolytic dissociation of C−H bond with low energy barrier of 0.48 eV. Applying CO decoration strategy to M1-ZSM-5 (M=Pd, Rh, Ru, Fe) enables improvement of oxygenates productivity by 3.2–11.3 times, highlighting the generalizability of this method in tuning metal-oxo electronic structure of SACs for efficient DMC process. 相似文献
5.
Xuemei Zhou 《物理化学学报》1985,37(6):2008064-0
Titania (TiO2) has been among the most widely investigated and used metal oxides over the past years, as it has various functional applications. Extensive research into TiO2 and industrial interest in this material have been triggered by its high abundance, excellent corrosion resistance, and low cost. To improve the activity of TiO2 in heterogeneous catalytic reactions, noble metals are used to accelerate the reactions. However, in the case of nanoparticles supported on TiO2, the active sites are usually limited to the peripheral sites of the noble metal particles or at the interface between the particle and the support. Thus, highly dispersed single metal atoms are desired for the effective utilization of precious noble metals. The study of oxide-supported isolated atoms, the so-called single-atom catalysts (SACs), was pioneered by Zhang's group. The high dispersion of precious noble metals results helps reduce the cost associated with catalyst preparation. Because of the presence of active centers as single atoms, the deactivation of metal atoms during the reaction, e.g., by coking for large agglomerates, is retarded. The unique coordination environment of the noble metal center provides special sites for the reaction, consequently increasing the selectivity of the reaction, including the enantioselectivity and stereoselectivity. Hence, supported SACs can bridge homogenous and heterogeneous reactions in solution as they provide selective reaction sites and are recyclable. Moreover, owing to the high site homogeneity of the isolated metal atoms, SACs are ideal models for establishing the structure-activity relationships. The present review provides an overview of recent works on the synthesis, characterization, and photocatalytic applications of SACs (Pt1, Pd1, Ir1, Rh1, Cu1, Ru1) supported on TiO2. The preparation of single atoms on TiO2 includes the creation of surface defective sites, surface modification, stabilization by high-temperature shockwave treatment, and metal-ligand self-assembly. Conventional characterization methods are categorized as microscopic imaging and spectroscopic methods, such as aberration-corrected scanning transmission electron microscopy (STEM), scanning tunneling microscopy (STM), extended X-ray absorption fine structure analysis (EXAFS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). We attempted to address the critical factors that lead to the stabilization of single-metal atoms on TiO2, and elucidate the mechanism underlying the photocatalytic hydrogen evolution and CO2 reduction. Although many fascinating applications of TiO2-supported SACs in photocatalysis could only be addressed superficially and in a referencing manner, we hope to provide interested readers with guidelines based on the wide literature, and more specifically, to provide a comprehensive overview of TiO2-supported SACs. 相似文献
6.
Dr. Zhiping Zheng Dr. Qiaorong Jiang Dr. Xiqing Cheng Dr. Xiao Han Prof. Qin Kuang Prof. Zhaoxiong Xie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(4):e202103521
Ethanol is a promising liquid clean energy source in the energy conversion field. However, the self-poisoning caused by the strongly adsorbed reaction intermediates (typically, CO) is a critical problem in ethanol oxidation reaction. To address this issue, we proposed a joint use of two strategies, alloying of Pt with other metals and building Pt/metal-oxide interfaces, to achieve high-performance electrocatalytic ethanol oxidation. For this, a well-designed synthetic route combining wet impregnation with a two-step thermal treatment process was established to construct PtSn/SnOx interfaces on carbon nanotubes. Using this route, the alloying of Pt−Sn and formation of PtSn−SnOx interfaces can simultaneously be achieved, and the coverage of SnOx thin films on PtSn alloy nanoparticles can be facilely tuned by the strong interaction between Pt and SnOx. The results revealed that the partial coverage of SnOx species not only retained the active sites, but also enhanced the CO anti-poisoning ability of the catalyst. Consequently, the H−PtSn/SnOx/CNT-2 catalyst with an optimized PtSn−SnOx interface showed significantly improved performances toward the ethanol oxidation reaction (825 mA mgPt−1). This study provides deep insights into the structure-performance relationship of PtSn/metal oxide composite catalysts, which would be helpful for the future design and fabrication of high-performance Pt-based ethanol oxidation reaction catalysts. 相似文献
7.
Mengmiao Sun Guanzheng Wu Jiadi Jiang Yidong Yang Aijun Du Lei Dai Xin Mao Qing Qin 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301957
The electrochemical NO3− reduction and its coupling with CO2 can provide novel and clean routes to synthesize NH3 and urea, respectively. However, their practical application is still impeded by the lack of efficient catalysts with desirable Faradaic efficiency (FE) and yield rate. Herein, we report the synthesis of molybdenum oxide nanoclusters anchored on carbon black (MoOx/C) as electrocatalyst. It affords an outstanding FE of 98.14 % and NH3 yield rate of 91.63 mg h−1 mgcat.−1 in NO3− reduction. Besides, the highest FE of 27.7 % with a maximum urea yield rate of 1431.5 μg h−1 mgcat.−1 toward urea is also achieved. The formation of electron-rich MoOx nanoclusters with highly unsaturated metal sites in the MoOx/C heterostructure is beneficial for enhanced catalytic performance. Studies on the mechanism reveal that the stabilization of *NO and *CO2NOOH intermediates are critical for the NH3 and urea synthesis, respectively. 相似文献
8.
Guanghui Feng Dr. Shibin Wang Prof. Shenggang Li Ruipeng Ge Dr. Xuefei Feng Prof. Junwei Zhang Dr. Yanfang Song Dr. Xiao Dong Jiazhou Zhang Prof. Gaofeng Zeng Prof. Qiang Zhang Prof. Guijun Ma Dr. Yi-De Chuang Prof. Xixiang Zhang Prof. Jinghua Guo Prof. Yuhan Sun Prof. Wei Wei Prof. Wei Chen 《Angewandte Chemie (International ed. in English)》2023,62(15):e202218664
Using sunlight to produce valuable chemicals and fuels from carbon dioxide (CO2), i.e., artificial photosynthesis (AP) is a promising strategy to achieve solar energy storage and a negative carbon cycle. However, selective synthesis of C2 compounds with a high CO2 conversion rate remains challenging for current AP technologies. We performed CO2 photoelectroreduction over a graphene/silicon carbide (SiC) catalyst under simulated solar irradiation with ethanol (C2H5OH) selectivity of>99 % and a CO2 conversion rate of up to 17.1 mmol gcat−1 h−1 with sustained performance. Experimental and theoretical investigations indicated an optimal interfacial layer to facilitate the transfer of photogenerated electrons from the SiC substrate to the few-layer graphene overlayer, which also favored an efficient CO2 to C2H5OH conversion pathway. 相似文献
9.
Jing Xu Ying Wang Ke Wang Meng Zhao Rui Zhang Wenjie Cui Li Liu Dr. Megalamane S. Bootharaju Dr. Jeong Hyun Kim Prof. Taeghwan Hyeon Prof. Hongjie Zhang Prof. Yu Wang Prof. Shuyan Song Prof. Xiao Wang 《Angewandte Chemie (International ed. in English)》2023,62(28):e202302877
Reducible oxide-supported noble metal nanoparticles exhibit high activity in catalyzing many important oxidation reactions. However, atom migration under harsh reaction conditions leads to deactivation of the catalyst. Meanwhile, single-atom catalysts demonstrate enhanced stability, but often suffer from poor catalytic activity owing to the ionized surface states. In this work, we simultaneously address the poor activity and stability issues by synthesizing highly active and durable rhodium (Rh) single-atom catalysts through a “wrap-bake-peel” process. The pre-coated SiO2 layer during synthesis of catalyst plays a crucial role in not only protecting CeO2 support against sintering, but also donating electron to weaken the Ce−O bond, producing highly loaded Rh single atoms on the CeO2 support exposed with high-index {210} facets. Benefiting from the unique electronic structure of CeO2 {210} facets, more oxygen vacancies are generated along with the deposition of more electropositive Rh single atoms, leading to remarkably improved catalytic performance in CO oxidation. 相似文献
10.
采用等体积浸渍法制备了以分子筛为载体的铜基无汞催化剂(Cu/HY),在固定床反应器中,考察了Cu/HY催化剂用于乙炔氢氯化反应制取氯乙烯的催化性能,并采用扫描电子显微镜(SEM)、能量散射光谱(EDS)、电感耦合等离子光谱(ICP-AES)、氮气吸脱附(BET)、热重分析(TG)、透射电子显微镜(TEM)、X射线粉末衍射(XRD)和X射线光电子能谱(XPS)表征手段对反应前后的催化剂进行了表征和分析。 结果表明,反应温度为160 ℃,常压,空速为120 h-1,V(HCl)/V(C2H2)=1.25,Cu的负载质量分数为15%时,Cu/HY催化剂的乙炔氢氯化性能最佳,乙炔转化率可达84%,氯乙烯选择性始终大于95%,且具有较好的稳定性;通过表征分析,认为催化剂表面形成积碳,铜活性物种的还原、团聚和流失是导致Cu/HY催化剂活性下降的主要原因。 相似文献
11.
Dr. Zedong Zhang Jiexin Zhu Dr. Shenghua Chen Prof. Wenming Sun Prof. Dingsheng Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202215136
Precise design and tuning of the micro-atomic structure of single atom catalysts (SACs) can help efficiently adapt complex catalytic systems. Herein, we inventively found that when the active center of the main group element gallium (Ga) is downsized to the atomic level, whose characteristic has significant differences from conventional bulk and rigid Ga catalysts. The Ga SACs with a P, S atomic coordination environment display specific flow properties, showing CO products with FE of ≈92 % at −0.3 V vs. RHE in electrochemical CO2 reduction (CO2RR). Theoretical simulations demonstrate that the adaptive dynamic transition of Ga optimizes the adsorption energy of the *COOH intermediate and renews the active sites in time, leading to excellent CO2RR selectivity and stability. This liquid single atom catalysts system with dynamic interfaces lays the foundation for future exploration of synthesis and catalysis. 相似文献
12.
Qifeng Ding Dr. Yang Yu Dr. Fei Huang Lihui Zhang Prof. Jian-Guo Zheng Mingjie Xu Prof. Jonathan B. Baell Prof. He Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4592-4598
C−N bond formation is regarded as a very useful and fundamental reaction for the synthesis of nitrogen-containing molecules in both organic and pharmaceutical chemistry. Noble-metal and homogeneous catalysts have frequently been used for C−N bond formation, however, these catalysts have a number of disadvantages, such as high cost, toxicity, and low atom economy. In this work, a low-toxic and cheap iron complex (iron ethylene-1,2-diamine) has been loaded onto carbon nanotubes (CNTs) to prepare a heterogeneous single-atom catalyst (SAC) named Fe-Nx/CNTs. We employed this SAC in the synthesis of C−N bonds for the first time. It was found that Fe-Nx/CNTs is an efficient catalyst for the synthesis of C−N bonds starting from aromatic amines and ketones. Its catalytic performance was excellent, giving yields of up to 96 %, six-fold higher than the yields obtained with noble-metal catalysts, such as AuCl3/CNTs and RhCl3/CNTs. The catalyst showed efficacy in the reactions of thirteen aromatic amine substrates, without the need for additives, and seventeen enaminones were obtained. High-angle annular dark-field scanning transmission electron microscopy in combination with X-ray absorption spectroscopy revealed that the iron species were well dispersed in the Fe-Nx/CNTs catalyst as single atoms and that Fe-Nx might be the catalytic active species. This Fe-Nx/CNTs catalyst has potential industrial applications as it could be cycled seven times without any significant loss of activity. 相似文献
13.
利用程序升温还原(TPR)、X-射线衍射(XRD)、CO吸附-红外光谱(CO-IR)、电子顺磁共振(EPR)和微型催化反应评价等手段, 研究了负载Pd/γ-Al2O3, Pd/TiO2和Pd-Ag/TiO2催化剂的结构和乙炔选择性加氢催化性能. 结果表明, Pd/TiO2催化剂具有较Pd/γ-Al2O3催化剂更优良的乙炔选择性加氢催化性能, 这与Pd-TiO2之间的强相互作用密切相关. Pd-TiO2之间的强相互作用不仅使负载型钯金属催化剂具有较高的乙炔加氢催化选择性, 而且具有较高的乙炔加氢催化活性. Pd/TiO2催化剂中添加Ag 组分后, Pd金属可促进Ag+的还原并可能形成Pd-Ag合金, 催化剂的乙烯选择性虽有所增加, 但乙炔转化率和乙烯收率下降. 相似文献
14.
Anatase TiO2 nanospindles containing 89% exposed {101} facets (TiO2-101) and nanosheets with 77% exposed {001} facets (TiO2-001) were hydrothermally synthesized and used as supports for Pd catalysts. The effects of the TiO2 materials on the catalytic performance of Pd/TiO2-101 and Pd/TiO2-001 catalysts were investigated in the selective hydrogenation of acetylene to polymer-grade ethylene. The Pd/TiO2-101 catalyst exhibited enhanced performance in terms of acetylene conversion and ethylene yield. To understand these effects, the catalysts were characterized by H2 temperature-programmed desorption (H2-TPD), H2 temperatureprogrammed reduction (H2-TPR), transmission electron microscopy (TEM), pulse CO chemisorption, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The TEM and CO chemisorption results confirmed that Pd nanoparticles (NPs) on the TiO2-101 support had a smaller average particle size (1.53 nm) and a higher dispersion (15.95%) than those on the TiO2-001 support (average particle size of 4.36 nm and dispersion of 9.06%). The smaller particle size and higher dispersion of Pd on the Pd/TiO2-101 catalyst provided more reaction active sites, which contributed to the improved catalytic activity of this supported catalyst. 相似文献
15.
Fen Su Dr. Juan Zou Xiaokang Lv Fengfei Lu Yijie Long Kun Tang Benpeng Li Prof. Dr. Huifang Chai Prof. Xingxing Wu Prof. Dr. Yonggui Robin Chi 《Angewandte Chemie (International ed. in English)》2023,62(23):e202303388
The development of catalyst-controlled methods for direct functionalization of two distinct C−H bonds represents an appealing approach for C−C formations in synthetic chemistry. Herein, we describe an organocatalytic approach for straightforward acylation of C(sp3)−H bonds employing readily available aldehyde as “acyl source” involving dehydrogenative coupling of aldehydes with ether, amine, or benzylic C(sp3)−H bonds. The developed method affords a broad range of ketones under mild conditions. Mechanistically, simple ortho-cyanoiodobenzene is essential in the oxidative radical N-heterocyclic carbene catalysis to give a ketyl radical and C(sp3) radical through a rarely explored intermolecular hydrogen atom transfer pathway, rendering the acylative C−C formations in high efficiency under a metal- and light-free catalytic conditions. Moreover, the prepared products show promising anti-bacterial activities that shall encourage further investigations on novel agrochemical development. 相似文献
16.
Jing Cao Tong Mou Bingbao Mei Pengfei Yao Ce Han Xue Gong Ping Song Prof. Zheng Jiang Prof. Thomas Frauenheim Prof. Jianping Xiao Prof. Weilin Xu 《Angewandte Chemie (International ed. in English)》2023,62(43):e202310973
Full understanding to the origin of the catalytic performance of a supported nanocatalyst from the points of view of both the active component and support is significant for the achievement of high performance. Herein, based on a model electrocatalyst of single-iridium-atom-doped iron (Fe)-based layered double hydroxides (LDH) for oxygen evolution reaction (OER), we reveal the first completed origin of the catalytic performance of such supported nanocatalysts. Specially, besides the activity enhancement of Ir sites by LDH support, the stability of surface Fe sites is enhanced by doped Ir sites: DFT calculation shows that the Ir sites can reduce the activity and enhance the stability of the nearby Fe sites; while further finite element simulations indicate, the stability enhancement of distant Fe sites could be attributed to the much low concentration of OER reactant (hydroxyl ions, OH−) around them induced by the much fast consumption of OH− on highly active Ir sites. These new findings about the interaction between the main active components and supports are applicable in principle to other heterogeneous nanocatalysts and provide a completed understanding to the catalytic performance of heterogeneous nanocatalysts. 相似文献
17.
Dr. Weixuan Nie Gavin P. Heim Nicholas B. Watkins Prof. Dr. Theodor Agapie Prof. Dr. Jonas C. Peters 《Angewandte Chemie (International ed. in English)》2023,62(12):e202216102
Electrochemical CO2 reduction (CO2R) at low pH is desired for high CO2 utilization; the competing hydrogen evolution reaction (HER) remains a challenge. High alkali cation concentration at a high operating current density has recently been used to promote electrochemical CO2R at low pH. Herein we report an alternative approach to selective CO2R (>70 % Faradaic efficiency for C2+ products, FEC2+) at low pH (pH 2; H3PO4/KH2PO4) and low potassium concentration ([K+]=0.1 M) using organic film-modified polycrystalline copper (Modified-Cu). Such an electrode effectively mitigates HER due to attenuated proton transport. Modified-Cu still achieves high FEC2+ (45 % with Cu foil /55 % with Cu GDE) under 1.0 M H3PO4 (pH≈1) at low [K+] (0.1 M), even at low operating current, conditions where HER can otherwise dominate. 相似文献
18.
为了提高Cu/USY催化剂在乙炔氢氯化反应中的催化活性,设计并成功制备了一系列离子液体修饰的分子筛负载的铜基催化剂(Cu@TPPB/USY).当铜和TPPB的百分含量均为15时,在反应温度为160℃,乙炔气体空速为120 h-1,氯化氢与乙炔的摩尔比为1.25:1的条件下,催化剂的乙炔转化率提升了1.17倍,氯乙烯选择性一直保持在98%以上.结合催化剂的傅里叶红外(FT-IR)、 N2物理吸脱附(BET)、热重分析(TG)、 X射线光电子能谱(XPS)、透射电镜(TEM)、 X射线衍射(XRD)、氢气程序升温还原(H2-TPR)和等离子体发射光谱(ICP-OES)的表征,认为TPPB的修饰不仅可以促进催化剂中Cu物种的分散,抑制其还原和流失,还能减少催化剂表面积碳、增强Cu活性物种与载体间的相互作用力,有效地提高Cu/USY催化剂的催化活性. 相似文献
19.
Prof. Yuanbin Zhang Wanqi Sun Prof. Binquan Luan Jiahao Li Dr. Dong Luo Yunjia Jiang Dr. Lingyao Wang Prof. Banglin Chen 《Angewandte Chemie (International ed. in English)》2023,62(37):e202309925
Separation of acetylene (C2H2) from carbon dioxide (CO2) or ethylene (C2H4) is industrially important but still challenging so far. Herein, we developed two novel robust metal organic frameworks AlFSIX-Cu-TPBDA (ZNU-8) with znv topology and SIFSIX-Cu-TPBDA (ZNU-9) with wly topology for efficient capture of C2H2 from CO2 and C2H4. Both ZNU-8 and ZNU-9 feature multiple anion functionalities and hierarchical porosity. Notably, ZNU-9 with more anionic binding sites and three distinct cages displays both an extremely large C2H2 capacity (7.94 mmol/g) and a high C2H2/CO2 (10.3) or C2H2/C2H4 (11.6) selectivity. The calculated capacity of C2H2 per anion (4.94 mol/mol at 1 bar) is the highest among all the anion pillared metal organic frameworks. Theoretical calculation indicated that the strong cooperative hydrogen bonds exist between acetylene and the pillared SiF62− anions in the confined cavity, which is further confirmed by in situ IR spectra. The practical separation performance was explicitly demonstrated by dynamic breakthrough experiments with equimolar C2H2/CO2 mixtures and 1/99 C2H2/C2H4 mixtures under various conditions with excellent recyclability and benchmark productivity of pure C2H2 (5.13 mmol/g) or C2H4 (48.57 mmol/g). 相似文献
20.
Dr. Tatsuhiko Yoshino Shun Satake Prof. Dr. Shigeki Matsunaga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(33):7346-7357
Transition-metal-catalyzed C−H functionalization reactions with Cp*MIII catalysts (M=Co, Rh, Ir) have found a wide variety of applications in organic synthesis. Albeit the intrinsic difficulties in achieving catalytic stereocontrol using these catalysts due to their lack of additional coordination sites for external chiral ligands and the conformational flexibility of the Cp ligand, catalytic enantioselective C−H functionalization reactions using the Group 9 metal triad with Cp-type ligands have been intensively studied since 2012. In this minireview, the progress in these reactions according to the type of the chiral catalyst used are summarized and discussed. The development of chiral Cpx ligands the metal complexes thereof, artificial metalloenzymes, chiral carboxylate-assisted enantioselective C−H activations, enantioselective alkylations assisted by chiral carboxylic acids or chiral sulfonates, and chiral transient directing groups are discussed. 相似文献