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1.
A Stable Microporous Mixed‐Metal Metal–Organic Framework with Highly Active Cu2+ Sites for Efficient Cross‐Dehydrogenative Coupling Reactions 下载免费PDF全文
Xiu‐Li Yang Chao Zou Dr. Yabing He Min Zhao Prof. Dr. Banglin Chen Prof. Dr. Shengchang Xiang Prof. Dr. Michael O'Keeffe Prof. Dr. Chuan‐De Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(5):1447-1452
Two metalloporphyrin octacarboxylates were used to link copper(II) nodes for the formation of two novel porous mixed‐metal metal–organic frameworks (M′MOFs) containing nanopore cages (2.1 nm in diameter) or nanotubular channels (1.5 nm in diameter). The highly active Cu2+ sites on the nanotubular surfaces of the stable porous M′MOF ZJU‐22 , stabilized by three‐connected nets, lead to the superior catalytic activity for the cross‐dehydrogenative coupling (CDC) reaction. 相似文献
2.
Silica‐Protection‐Assisted Encapsulation of Cu2O Nanocubes into a Metal–Organic Framework (ZIF‐8) To Provide a Composite Catalyst 下载免费PDF全文
Bo Li Dr. Jian‐Gong Ma Prof. Dr. Peng Cheng 《Angewandte Chemie (International ed. in English)》2018,57(23):6834-6837
The integration of metal/metal oxide nanoparticles (NPs) into metal–organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection–sacrifice (TPS) method to encapsulate metastable NPs such as Cu2O into MOFs. SiO2 was used as both a protective shell for Cu2O nanocubes and a sacrificial template for forming a yolk–shell structure. The obtained Cu2O@ZIF‐8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4‐nitrophenol with high activity. This is the first report of a Cu2O@MOF‐type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials. 相似文献
3.
Hydrogen Storage in a Potassium‐Ion‐Bound Metal–Organic Framework Incorporating Crown Ether Struts as Specific Cation Binding Sites 下载免费PDF全文
Dr. Dae‐Woon Lim Seung An Chyun Prof. Myunghyun Paik Suh 《Angewandte Chemie (International ed. in English)》2014,53(30):7819-7822
To develop a metal–organic framework (MOF) for hydrogen storage, SNU‐200 incorporating a 18‐crown‐6 ether moiety as a specific binding site for selected cations has been synthesized. SNU‐200 binds K+, NH4+, and methyl viologen(MV2+) through single‐crystal to single‐crystal transformations. It exhibits characteristic gas‐sorption properties depending on the bound cation. SNU‐200 activated with supercritical CO2 shows a higher isosteric heat (Qst) of H2 adsorption (7.70 kJ mol?1) than other zinc‐based MOFs. Among the cation inclusions, K+ is the best for enhancing the isosteric heat of the H2 adsorption (9.92 kJ mol?1) as a result of the accessible open metal sites on the K+ ion. 相似文献
4.
A Highly Stable Copper‐Based Catalyst for Clarifying the Catalytic Roles of Cu0 and Cu+ Species in Methanol Dehydrogenation 下载免费PDF全文
Huanhuan Yang Dr. Yanyan Chen Dr. Xiaojing Cui Guofu Wang Youliang Cen Dr. Tiansheng Deng Wenjun Yan Jie Gao Dr. Shanhui Zhu Prof. Unni Olsbye Prof. Jianguo Wang Prof. Weibin Fan 《Angewandte Chemie (International ed. in English)》2018,57(7):1836-1840
Identification of the active copper species, and further illustration of the catalytic mechanism of Cu‐based catalysts is still a challenge because of the mobility and evolution of Cu0 and Cu+ species in the reaction process. Thus, an unprecedentedly stable Cu‐based catalyst was prepared by uniformly embedding Cu nanoparticles in a mesoporous silica shell allowing clarification of the catalytic roles of Cu0 and Cu+ in the dehydrogenation of methanol to methyl formate by combining isotope‐labeling experiment, in situ spectroscopy, and DFT calculations. It is shown that Cu0 sites promote the cleavage of the O?H bond in methanol and of the C?H bond in the reaction intermediates CH3O and H2COOCH3 which is formed from CH3O and HCHO, whereas Cu+ sites cause rapid decomposition of formaldehyde generated on the Cu0 sites into CO and H2. 相似文献
5.
《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(1):288-297
Montmorillonite‐enwrapped copper and scandium catalysts (Cu2+‐ and Sc3+‐monts) were easily prepared by treating Na+‐mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu2+‐ and Sc3+‐monts showed outstanding catalytic activities for a variety of carbon–carbon bond‐forming reactions, such as the Michael reaction, the Sakurai–Hosomi allylation, and the Diels–Alder reaction, under solvent‐free or aqueous conditions. The remarkable activity of the mont catalysts is attributable to the negatively charged silicate layers that are capable of stabilizing metal cations. Furthermore, these catalysts were reusable without any appreciable loss in activity and selectivity. The Cu2+‐mont‐catalyzed Michael reaction proceeds via a ternary complex in which both the 1,3‐dicarbonyl compound and the enone are coordinated to a Lewis acid Cu2+ center. 相似文献
6.
Single Crystal‐to‐Single Crystal Site‐Selective Postsynthetic Metal Exchange in a Zn–MOF Based on Semi‐Rigid Tricarboxylic Acid and Access to Bimetallic MOFs 下载免费PDF全文
Dr. Alankriti Bajpai Pujari Chandrasekhar Dr. Savitha Govardhan Dr. Rahul Banerjee Prof. Dr. Jarugu Narasimha Moorthy 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2759-2765
The metal ions in a neutral Zn–MOF constructed from tritopic triacid H3L with inherent concave features, rigid core, and peripheral flexibility are found to exist in two distinct SBUs, that is, 0D and 1D. This has allowed site‐selective postsynthetic metal exchange (PSME) to be investigated and reactivities of the metal ions in two different environments in coordination polymers to be contrasted for the first time. Site‐selective transmetalation of Zn ions in the discrete environment is shown to occur in a single crystal‐to‐single crystal (SCSC) fashion, with metal ions such as Fe3+, Ru3+, Cu2+, Co2+, etc., whereas those that are part of 1D SBU sustain structural integrity, leading to novel bimetallic MOFs, which are inaccessible by conventional approaches. To the best of our knowledge, site‐selective postsynthetic exchange of an intraframework metal ion in a MOF that contains metal ions in discrete as well as polymeric SBUs is heretofore unprecedented. 相似文献
7.
Yang Wang Dr. Qi Liu Qin Zhang Bosi Peng Prof. Hexiang Deng 《Angewandte Chemie (International ed. in English)》2018,57(24):7120-7125
We report a new approach to create metal‐binding site in a series of metal–organic frameworks (MOFs), where tetratopic carboxylate linker, 4′,4′′,4′′′,4′′′′‐methanetetrayltetrabiphenyl‐4‐carboxylic acid, is partially replaced by a tritopic carboxylate linker, tris(4‐carboxybiphenyl)amine, in combination with monotopic linkers, formic acid, trifluoroacetic acid, benzoic acid, isonicotinic acid, 4‐chlorobenzoic acid, and 4‐nitrobenzoic acid, respectively. The distance between these paired‐up linkers can be precisely controlled, ranging from 5.4 to 10.8 Å, where a variety of metals, Mg2+, Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+ and Pb2+, can be placed in. The distribution of these metal‐binding sites across a single crystal is visualized by 3D tomography of laser scanning confocal microscopy with a resolution of 10 nm. The binding affinity between the metal and its binding‐site in MOF can be varied in a large range (observed binding constants, Kobs from 1.56×102 to 1.70×104 L mol?1), in aqueous solution. The fluorescence of these crystals can be used to detect biomarkers, such as cysteine, homocysteine and glutathione, with ultrahigh sensitivity and without the interference of urine, through the dissociation of metal ions from their binding sites. 相似文献
8.
Deependra M. Shakya Otega A. Ejegbavwo Thayalan Rajeshkumar Sanjaya D. Senanayake Amy J. Brandt Sharfa Farzandh Narayan Acharya Amani M. Ebrahim Anatoly I. Frenkel Ning Rui Gregory L. Tate John R. Monnier Konstantinos D. Vogiatzis Natalia B. Shustova Donna A. Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16685-16689
We report the first study of a gas‐phase reaction catalyzed by highly dispersed sites at the metal nodes of a crystalline metal–organic framework (MOF). Specifically, CuRhBTC (BTC3?=benzenetricarboxylate) exhibited hydrogenation activity, while other isostructural monometallic and bimetallic MOFs did not. Our multi‐technique characterization identifies the oxidation state of Rh in CuRhBTC as +2, which is a Rh oxidation state that has not previously been observed for crystalline MOF metal nodes. These Rh2+ sites are active for the catalytic hydrogenation of propylene to propane at room temperature, and the MOF structure stabilizes the Rh2+ oxidation state under reaction conditions. Density functional theory calculations suggest a mechanism in which hydrogen dissociation and propylene adsorption occur at the Rh2+ sites. The ability to tailor the geometry and ensemble size of the metal nodes in MOFs allows for unprecedented control of the active sites and could lead to significant advances in rational catalyst design. 相似文献
9.
Copper‐Doped CdSe/ZnS Quantum Dots: Controllable Photoactivated Copper(I) Cation Storage and Release Vectors for Catalysis 下载免费PDF全文
Joseph C. Bear Dr. Nathan Hollingsworth Dr. Paul D. McNaughter Dr. Andrew G. Mayes Dr. Michael B. Ward Prof. Thomas Nann Dr. Graeme Hogarth Prof. Ivan P. Parkin 《Angewandte Chemie (International ed. in English)》2014,53(6):1598-1601
The first photoactivated doped quantum dot vector for metal‐ion release has been developed. A facile method for doping copper(I) cations within ZnS quantum dot shells was achieved through the use of metal‐dithiocarbamates, with Cu+ ions elucidated by X‐ray photoelectron spectroscopy. Photoexcitation of the quantum dots has been shown to release Cu+ ions, which was employed as an effective catalyst for the Huisgen [3+2] cycloaddition reaction. The relationship between the extent of doping, catalytic activity, and the fluorescence quenching was also explored. 相似文献
10.
Zirconium–Porphyrin‐Based Metal–Organic Framework Hollow Nanotubes for Immobilization of Noble‐Metal Single Atoms 下载免费PDF全文
Ting He Dr. Shuangming Chen Bing Ni Yue Gong Zhao Wu Prof. Li Song Prof. Lin Gu Prof. Wenping Hu Prof. Xun Wang 《Angewandte Chemie (International ed. in English)》2018,57(13):3493-3498
Single atoms immobilized on metal–organic frameworks (MOFs) with unique nanostructures have drawn tremendous attention in the application of catalysis but remain a great challenge. Various single noble‐metal atoms have now been successfully anchored on the well‐defined anchoring sites of the zirconium porphyrin MOF hollow nanotubes, which are probed by aberration‐corrected scanning transmission electron microscopy and synchrotron‐radiation‐based X‐ray absorption fine‐structure spectroscopy. Owing to the hollow structure and excellent photoelectrochemical performance, the HNTM‐Ir/Pt exhibits outstanding catalytic activity in the visible‐light photocatalytic H2 evolution via water splitting. The single atom immobilized on MOFs with hollow structures are expected to pave the way to expand the potential applications of MOFs. 相似文献
11.
Copper(II) and Sodium(I) Complexes based on 3,7‐Diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide: Synthesis,Characterization, and Catalytic Activity 下载免费PDF全文
《化学:亚洲杂志》2018,13(19):2868-2880
The reaction of 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane (DAPTA) with metal salts of CuII or NaI/NiII under mild conditions led to the oxidized phosphane derivative 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide (DAPTA=O) and to the first examples of metal complexes based on the DAPTA=O ligand, that is, [CuII(μ‐CH3COO)2(κO‐DAPTA=O)]2 ( 1 ) and [Na(1κOO′;2κO‐DAPTA=O)(MeOH)]2(BPh4)2 ( 2 ). The catalytic activity of 1 was tested in the Henry reaction and for the aerobic 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO)‐mediated oxidation of benzyl alcohol. Compound 1 was also evaluated as a model system for the catechol oxidase enzyme by using 3,5‐di‐tert‐butylcatechol as the substrate. The kinetic data fitted the Michaelis–Menten equation and enabled the obtainment of a rate constant for the catalytic reaction; this rate constant is among the highest obtained for this substrate with the use of dinuclear CuII complexes. DFT calculations discarded a bridging mode binding type of the substrate and suggested a mixed‐valence CuII/CuI complex intermediate, in which the spin electron density is mostly concentrated at one of the Cu atoms and at the organic ligand. 相似文献
12.
Theoretical Insights into the Tuning of Metal Binding Sites of Paddlewheels in rht‐Metal–Organic Frameworks 下载免费PDF全文
Theoretical investigations of CO2 sorption are performed in four members of the highly tunable rht‐metal–organic framework (MOF) platform. rht‐MOFs contain two Cu2+ ions that comprise the metal paddlewheels and both are in chemically distinct environments. Indeed, one type of Cu2+ ion faces toward the center of the linker whereas the other type faces away from the center of the linker. Electronic structure calculations on the series of rht‐MOFs demonstrate that one of the Cu2+ ions has a consistently higher charge magnitude relative to the other. As a consequence, the Cu2+ ion with the higher partial positive charge acts as the favored sorbate binding site at initial loading as revealed by grand canonical Monte Carlo (GCMC) simulations that include many‐body polarization. It was found that the charge distribution about the copper paddlewheels is dependent on the type of functional groups present on the linker. This study demonstrates how the binding site about the metal paddlewheels in the rht‐MOF platform can be controlled by changing the functionality on the organic ligand. 相似文献
13.
Stabilization of Catalytically Active Cu+ Surface Sites on Titanium–Copper Mixed‐Oxide Films 下载免费PDF全文
Dr. Ashleigh E. Baber Dr. Xiaofang Yang Dr. Hyun You Kim Dr. Kumudu Mudiyanselage Markus Soldemo Dr. Jonas Weissenrieder Dr. Sanjaya D. Senanayake Dr. Abdullah Al‐Mahboob Dr. Jerzy T. Sadowski Dr. Jaime Evans Dr. José A. Rodriguez Dr. Ping Liu Dr. Friedrich M. Hoffmann Dr. Jingguang G. Chen Dr. Darío J. Stacchiola 《Angewandte Chemie (International ed. in English)》2014,53(21):5336-5340
The oxidation of CO is the archetypal heterogeneous catalytic reaction and plays a central role in the advancement of fundamental studies, the control of automobile emissions, and industrial oxidation reactions. Copper‐based catalysts were the first catalysts that were reported to enable the oxidation of CO at room temperature, but a lack of stability at the elevated reaction temperatures that are used in automobile catalytic converters, in particular the loss of the most reactive Cu+ cations, leads to their deactivation. Using a combined experimental and theoretical approach, it is shown how the incorporation of titanium cations in a Cu2O film leads to the formation of a stable mixed‐metal oxide with a Cu+ terminated surface that is highly active for CO oxidation. 相似文献
14.
Metallic Single‐Unit‐Cell Orthorhombic Cobalt Diselenide Atomic Layers: Robust Water‐Electrolysis Catalysts 下载免费PDF全文
Liang Liang Dr. Hao Cheng Fengcai Lei Dr. Jun Han Shan Gao Dr. Chengming Wang Prof. Yongfu Sun Shaista Qamar Prof. Shiqiang Wei Prof. Yi Xie 《Angewandte Chemie (International ed. in English)》2015,54(41):12004-12008
The bottleneck in water electrolysis lies in the kinetically sluggish oxygen evolution reaction (OER). Herein, conceptually new metallic non‐metal atomic layers are proposed to overcome this drawback. Metallic single‐unit‐cell CoSe2 sheets with an orthorhombic phase are synthesized by thermally exfoliating a lamellar CoSe2‐DETA hybrid. The metallic character of orthorhombic CoSe2 atomic layers, verified by DFT calculations and temperature‐dependent resistivities, allows fast oxygen evolution kinetics with a lowered overpotential of 0.27 V. The single‐unit‐cell thickness means 66.7 % of the Co2+ ions are exposed on the surface and serve as the catalytically active sites. The lowered Co2+ coordination number down to 1.3 and 2.6, gives a lower Tafel slope of 64 mV dec?1 and higher turnover frequency of 745 h?1. Thus, the single‐unit‐cell CoSe2 sheets have around 2 and 4.5 times higher catalytic activity compared with the lamellar CoSe2‐DETA hybrid and bulk CoSe2. 相似文献
15.
Versatile Tailoring of Paddle‐Wheel ZnII Metal–Organic Frameworks through Single‐Crystal‐to‐Single‐Crystal Transformations 下载免费PDF全文
Tapan K. Pal Dr. Subhadip Neogi Prof. Parimal K. Bharadwaj 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):16083-16090
A new tetracarboxylate ligand having short and long arms formed 2D layer ZnII coordination polymer 1 with paddle‐wheel secondary building units under solvothermal conditions. The framework undergoes solvent‐specific single crystal‐to‐single crystal (SC‐SC) transmetalation to produce 1Cu . With a sterically encumbered dipyridyl linker, the same ligand forms non‐interpenetrated, 3D, pillared‐layer ZnII metal–organic framework (MOF) 2 , which takes part in SC‐SC linker‐exchange reactions to produce three daughter frameworks. The parent MOF 2 shows preferential incorporation of the longest linker in competitive linker‐exchange experiments. All the 3D MOFs undergo complete SC‐SC transmetalation with CuII, whereby metal exchange in different solvents and monitoring of X‐ray structures revealed that bulky solvated metal ions lead to ordering of the shortest linker in the framework, which confirms that the solvated metal ions enter through the pores along the linker axis. 相似文献
16.
The Crystal Structure of a Homodimeric Pseudomonas Glyoxalase I Enzyme Reveals Asymmetric Metallation Commensurate with Half‐of‐Sites Activity 下载免费PDF全文
Dr. Rohan Bythell‐Douglas Dr. Uthaiwan Suttisansanee Dr. Gavin R. Flematti Michael Challenor Dr. Mihwa Lee Dr. Santosh Panjikar Prof. John F. Honek Prof. Charles S. Bond 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):541-544
The Zn inactive class of glyoxalase I (Glo1) metalloenzymes are typically homodimeric with two metal‐dependent active sites. While the two active sites share identical amino acid composition, this class of enzyme is optimally active with only one metal per homodimer. We have determined the X‐ray crystal structure of GloA2, a Zn inactive Glo1 enzyme from Pseudomonas aeruginosa. The presented structures exhibit an unprecedented metal‐binding arrangement consistent with half‐of‐sites activity: one active site contains a single activating Ni2+ ion, whereas the other contains two inactivating Zn2+ ions. Enzymological experiments prompted by the binuclear Zn2+ site identified a novel catalytic property of GloA2. The enzyme can function as a Zn2+/Co2+‐dependent hydrolase, in addition to its previously determined glyoxalase I activity. The presented findings demonstrate that GloA2 can accommodate two distinct metal‐binding arrangements simultaneously, each of which catalyzes a different reaction. 相似文献
17.
Huan Liu Yingying Chen Yan Cheng Qingji Xie Rushi Liu Xiaoping Yang 《Electroanalysis》2020,32(8):1754-1762
Immunoassay of amino‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) was conducted using Cu2+‐1,3,5‐benzenetricarboxylic acid metal‐organic frameworks (HKUST‐1 MOFs) as the secondary antibody label, and in situ microliter‐droplet anodic stripping voltammetry detection of Cu2+ in 0.1 M HNO3+1 M NaCl directly on the glassy carbon immunoelectrode. Electrochemical methods, quartz crystal microbalance, scanning electron microscopy and energy dispersive spectroscopy were employed for material and electrode characterizations. Under optimized conditions, the limit of detection (S/N=3) was 0.33 fg mL?1, and the analysis of NT‐proBNP in clinical serum samples returned good results. 相似文献
18.
The Origin of the Selectivity and Activity of Ruthenium‐Cluster Catalysts for Fuel‐Cell Feed‐Gas Purification: A Gas‐Phase Approach 下载免费PDF全文
Dr. Sandra M. Lang Prof. Dr. Thorsten M. Bernhardt Marjan Krstić Prof. Dr. Vlasta Bonačić‐Koutecký 《Angewandte Chemie (International ed. in English)》2014,53(21):5467-5471
Gas‐phase ruthenium clusters Run+ (n=2–6) are employed as model systems to discover the origin of the outstanding performance of supported sub‐nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed‐gas purification for advanced fuel‐cell applications. Using ion‐trap mass spectrometry in conjunction with first‐principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre‐formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru‐atom sites with a low number of metal–metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl‐type intermediate. 相似文献
19.
Ligand and Metal Effects on the Stability and Adsorption Properties of an Isoreticular Series of MOFs Based on T‐Shaped Ligands and Paddle‐Wheel Secondary Building Units 下载免费PDF全文
Ying Xiong Yan‐Zhong Fan Dr. Daiane Damasceno Borges Cheng‐Xia Chen Zhang‐Wen Wei Hai‐Ping Wang Dr. Mei Pan Dr. Ji‐Jun Jiang Prof. Guillaume Maurin Prof. Cheng‐Yong Su 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(45):16147-16156
The synthesis of stable porous materials with appropriate pore size and shape for desired applications remains challenging. In this work a combined experimental/computational approach has been undertaken to tune the stability under various conditions and the adsorption behavior of a series of MOFs by subtle control of both the nature of the metal center (Co2+, Cu2+, and Zn2+) and the pore surface by the functionalization of the organic linkers with amido and N‐oxide groups. In this context, six isoreticular MOFs based on T‐shaped ligands and paddle‐wheel units with ScD0.33 topology have been synthesized. Their stabilities have been systematically investigated along with their ability to adsorb a wide range of gases (N2, CO2, CH4, CO, H2, light hydrocarbons (C1–C4)) and vapors (alcohols and water). This study has revealed that the MOF frameworks based on Cu2+ are more stable than their Co2+ and Zn2+ analogues, and that the N‐oxide ligand endows the MOFs with a higher affinity for CO2 leading to excellent selectivity for this gas over other species. 相似文献
20.
Christopher Paolucci Anuj A. Verma Shane A. Bates Vincent F. Kispersky Jeffrey T. Miller Rajamani Gounder W. Nicholas Delgass Fabio H. Ribeiro William F. Schneider 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(44):12022-12027
Operando X‐ray absorption experiments and density functional theory (DFT) calculations are reported that elucidate the role of copper redox chemistry in the selective catalytic reduction (SCR) of NO over Cu‐exchanged SSZ‐13. Catalysts prepared to contain only isolated, exchanged CuII ions evidence both CuII and CuI ions under standard SCR conditions at 473 K. Reactant cutoff experiments show that NO and NH3 together are necessary for CuII reduction to CuI. DFT calculations show that NO‐assisted NH3 dissociation is both energetically favorable and accounts for the observed CuII reduction. The calculations predict in situ generation of Brønsted sites proximal to CuI upon reduction, which we quantify in separate titration experiments. Both NO and O2 are necessary for oxidation of CuI to CuII, which DFT suggests to occur by a NO2 intermediate. Reaction of Cu‐bound NO2 with proximal NH4+ completes the catalytic cycle. N2 is produced in both reduction and oxidation half‐cycles. 相似文献