Arrangement Of Cu Research Articles

Seeding as a Decisive Tool for Increasing Space-Time-Yields in the Preparation of High-Quality Cu/ZnO/ZrO2 Catalysts

Aging is one of the key steps in the preparation of highly active Cu/ZnO-based catalysts for use in the production of methanol. If certain pH and temperature specifications are met, an initially amorphous precipitate transforms into the crystalline precursor phase of zincian malachite, which is characterized by a periodic arrangement of Cu and Zn atoms and has proven advantageous for the quality of the final catalyst. However, aging generally takes between 30 min and multiple hours until the desired phase transformation is completed. With our study, we show that aging can be significantly accelerated by seeding the freshly precipitated suspension with already aged zincian malachite crystals: the necessary aging time was reduced by 41% for seeding mass fractions as low as 3 wt.% and from 83 min to less than 2 min for 30 wt.% seeds. No negative influence of seeding on the phase composition, specific surface area, molar metal ratios, or the morphology of the aged precursor could be identified. Consequently, the catalyst performance in the synthesis of methanol from CO2, as well as from a CO/CO2 mixture, was identical to a catalyst from an unseeded preparation and showed small advantages compared to a commercial sample. Thus, we conclude that seeding is a vital tool to accelerate the preparation of all Cu/Zn-based catalysts while maintaining product quality, presumably also on an industrial scale.

Hirshfeld surface and fingerprint plot analysis of non-covalent interaction (NCI) in CuII −based catecholase models

Understanding of molecular packing is one of the favorable modes to study the mechanistic behavior of a supramolecular system. The present study aims in analyzing the molecular packing and supramolecular arrangement of Cu+2-catecholase system [C13H13BrCuN4O2 (System A), C14H17BrCuN4O3 (System B), and C20H36Cl2Cu2N4O11 ((System C)] with variable auxiliary groups. These systems are well studied for their reversible binding with oxygen and catalytic property towards oxidation of ortho-diphenol. The primary novelty of such study is elucidating the architecture of auxiliary part of the system whose influence is studied but not understood in terms of the molecular packing. The respective supramolecular arrangement of the Cu (II) systems having such auxiliary part is reported herein which illustrates the interaction efficacy with macromolecules like proteins. The respective non covalent interactions (NCI) of aforementioned three antiferromagnetic Cu (II) species are reported using Hirsfeld analyses which also helps in the correlation of structure–property interaction.

Ordering Bimetallic Cu-Pd Catalysts onto Orderly Mesoporous SrTiO3-Crystal Nanotubular Networks for Efficient Carbon Dioxide Photoreduction.

Artificial photosynthesis of fuels has garnered significant attention, with SrTiO3 emerging as a potential candidate for photocatalysis due to its exceptional physicochemical properties. However, selectively converting CO2 into fuels with desired reaction products remains a grand challenge. Herein, we design an updated method via an aging strategy based on the electrospinning technique to synthesize a single-crystalline Al-doped SrTiO3 nanotubular networks with self-assembled orderly mesopores, further modified by Cu-Pd alloy. It exhibits both high crystallinity and superior cross-linked mesoporous structures, effectively facilitating charge carrier transfer, photon utilization, and mass transfer, with a remarkable enhancement from 0.025 mmol h-1 m-2 to 1.090 mmol h-1 m-2 in the CO production rate. Meanwhile, the ordered arrangement of Cu and Pd atoms on the (111) surface can promote the rate-determining step (*CO2 to *COOH), which is also responsible for its good activity. The presence of CuO in the reaction confers a significant advantage for CO desorption, leading to a remarkable CO selectivity of 95.54 %. This work highlights new insights into developing advanced heterogeneous photocatalysts.

Ordering Bimetallic Cu‐Pd Catalysts onto Orderly Mesoporous SrTiO3‐Crystal Nanotubular Networks for Efficient Carbon Dioxide Photoreduction

AbstractArtificial photosynthesis of fuels has garnered significant attention, with SrTiO3 emerging as a potential candidate for photocatalysis due to its exceptional physicochemical properties. However, selectively converting CO2 into fuels with desired reaction products remains a grand challenge. Herein, we design an updated method via an aging strategy based on the electrospinning technique to synthesize a single‐crystalline Al‐doped SrTiO3 nanotubular networks with self‐assembled orderly mesopores, further modified by Cu−Pd alloy. It exhibits both high crystallinity and superior cross‐linked mesoporous structures, effectively facilitating charge carrier transfer, photon utilization, and mass transfer, with a remarkable enhancement from 0.025 mmol h−1 m−2 to 1.090 mmol h−1 m−2 in the CO production rate. Meanwhile, the ordered arrangement of Cu and Pd atoms on the (111) surface can promote the rate‐determining step (*CO2 to *COOH), which is also responsible for its good activity. The presence of CuO in the reaction confers a significant advantage for CO desorption, leading to a remarkable CO selectivity of 95.54 %. This work highlights new insights into developing advanced heterogeneous photocatalysts.

Coordination polymers and supramolecular cages based on [(MS4)Cux]x−2 cluster units and N-containing ligands

This work demonstrates that the number and arrangement of Cu+ around the (MS4)2− core can be varied with the synthesis conditions, affording heterothiometallic [(MS4)Cux]x−2 cluster units with versatile geometries and connectivities for building CPs.

The impact of spatially heterogeneous chemical doping on the electronic properties of CdSe quantum dots: insights from ab initio computation.

The introduction of copper (Cu) impurity in semiconductor CdSe quantum dots (QDs) gives rise to unique photoluminescence (PL) bands exhibiting distinctive characteristics, like broad line width, significant Stokes shift, and complex temporal decay. The atomistic origins of these spectral features are yet to be understood comprehensively. We employed multiple computational techniques to systematically study the impact of the spatial heterogeneity of Cu atoms on the stability and photophysical properties, including the emission linewidth of doped QDs under ambient conditions. The Cu substitution introduces a spin-polarized intragap state, the energetic position of which is strongly dependent on the dopant location and causes spectral broadening in QD ensembles. Furthermore, the dopant dynamics under ambient conditions are significantly influenced by the specific arrangement of Cu within the QDs. The dynamic electronic structures of surface-doped CdSe illustrate more pronounced perturbations and vary the mid-gap state position more drastically than those of the core-doped QDs. Vibronic coupling broadens the photoluminescence peaks associated with the conduction band-to-defect level transition for individual QDs. These insights into the dynamic structure-photophysical property relationship suggest viable approaches, such as tuning the operational temperature and selective co-doping, to enhance the functional performances of doped CdSe QDs strategically.

Cu-Bx (X: N, CN, P) Composites for CO2 Electroreduction: Materials Vs. Gas Diffusion Electrode Characteristics

The conversion of CO2 is an attractive strategy towards the mitigation of environmental pollution, and the production of bulk chemicals and fuels by renewables. In the field of CO2 electroreduction, copper constitutes the most versatile catalyst, being able to generate CO, C2H4, CH4, as well as alcohols and acids from CO2. Lately, research on Cu-based CO2 electroreduction has focused on two main topics: firstly, the operation under elevated current densities through the development of stable and selective gas diffusion electrodes (GDEs), and electrolyzers; secondly, the tuning of the selectivity of Cu-catalysts towards a specific product. Regarding the latter, common methods, include doping with other metals and heteroatoms, alloying, as well as creating electrode architectures consisting often of Cu/Ag and Cu/Zn structures.Contrary to Cu, only a few heterogeneous electrocatalysts have shown the ability to generate more complex molecules beyond CO and HCOOH, such as hydrocarbons and alcohols. Among these catalysts, the chemically robust and synthetically scalable, boron phosphide (BP) has shown the ability to favor the production of CH3OH from CO2 under low current densities of ca. 2 mA cm-2.Aiming to achieve a synergistic effect between Cu and BP, we herein investigate the role of electrode characteristics versus material properties in gas diffusion electrodes under industrially relevant current densities > 100 mA cm-2. Starting from GDE-properties, we report on the influence of the layer arrangement of Cu and BP on the surface of the GDL, their mixing ratio as well as the deposition method and cell type on the CO2 electroreduction. Furthermore, in order to elucidate the role of material properties towards deciding the product spectrum, we compared the activity of B-compounds with different structural characteristics, possessing cubic as well as hexagonal structures. Concretely, cubic boron nitride (c-BN), and phosphide (BP) as well as hexagonal boron carbon nitride (h-BCN), and hexagonal BN (h-BN) are evaluated in a series of Cu-based GDEs. Depending on the selected layer arrangement, material combination and mixing ratio we are able to steer the main CO2RR product to either CO, C2H4 or CH4 at 200 mA cm-2. Beyond Cu-BX GDEs, our results demonstrate that in the case of synergistic effects, material/electrocatalyst development and electrode/electrolyzer architecture must go hand-in-hand, providing important strategies towards the optimization of composite electrocatalysts. Figure 1

Molecular Dynamics Simulation of the Coalescence and Melting Process of Cu and Ag Nanoparticles

The coalescence and melting process of different sizes and arrangements of Ag and Cu nanoparticles is studied through the molecular dynamics (MD) method. The results show that the twin boundary or stacking fault formation and atomic diffusion of the nanoparticles play an important role in the different stages of the heating process. At the beginning of the simulation, Cu and Ag nanoparticles will contact to each other in a very short time. As the temperature goes up, Cu and Ag nanoparticles may generate stacking fault or twin boundary to stabilize the interface structure. When the temperature reaches a critical value, the atoms gain a strong ability to diffuse and eventually melt into one liquid sphere. The coalescence point and melting temperature increase as cluster diameter increases. Moreover, the arrangement of Cu and Ag nanoparticles has a certain effect on the stability of the initial joint interface, which will affect subsequent coalescence and melting behavior.

The role of Ru passivation and doping on the barrier and seed layer properties of Ru-modified TaN for copper interconnects.

Size reduction of the barrier and liner stack for copper interconnects is a major bottleneck in further down-scaling of transistor devices. The role of the barrier is to prevent diffusion of Cu atoms into the surrounding dielectric, while the liner (also referred to as a seed layer) ensures that a smooth Cu film can be electroplated. Therefore, a combined barrier + liner material that restricts the diffusion of Cu into the dielectric and allows for copper electro-deposition is needed. In this paper, we have explored barrier + liner materials composed of 1 and 2 monolayers (MLs) of Ru-passivated ϵ-TaN and Ru doped ϵ-TaN and focused on their interactions with Cu through the adsorption of small Cu clusters with 1-4 atoms. Moreover, different doping patterns for Ru doping in TaN are investigated to understand how selective doping of the ϵ-TaN surface influences surface stability. We found that an increased concentration of Ru atoms in the outermost Ta layer improves the adhesion of Cu. The strongest binding of the Cu atoms was found on the 100% Ru doped surface followed by the 1 ML Ru passivated surface. These two surfaces are recommended for the combined barrier + liner for Cu interconnects. The closely packed arrangements of Cu were found to exhibit weak Cu-slab and strong Cu-Cu interactions, whereas the sparse arrangements of Cu exhibit strong Cu-slab and weak Cu-Cu interactions. The Cu atoms seem to bind more favorably when they are buried in the doped or passivated surface layer due to the increase in their coordination number. This is facilitated by the surface distortion arising from the ionic radius mismatch between Ta and Ru. We also show that the strong Cu-Cu interaction alone cannot predict the association of Cu atoms as a few 2D Cu clusters showed stronger Cu-Cu interaction than the 3D clusters, highlighting the importance of Cu-surface interactions.

Unraveling the effect of B-site antisite defects on the electronic and magnetic properties of the quadruple perovskite CaCu3Fe2Nb2O12.

The atomic-scale degree of B/B' alternate cationic disorder is known to significantly influence the macroscopic properties of the quadruple perovskites AA3'B2B2'O12; however, the nature of this disorder has rarely been critically studied. Herein, the effect of B-site cationic arrangement on the electronic and magnetic properties of the quadruple perovskite CaCu3Fe2Nb2O12 was systemically investigated using the first-principles calculations. The results demonstrate that the B-site ordered CaCu3Fe2Nb2O12 is a ferrimagnetic insulator with antiferromagnetic coupling between the A'-site Cu and B-site Fe. The calculated total magnetic moment is 7.00 μB f.u.-1, which is apparently larger than the experimentally measured saturation magnetization because of different degrees of the B-site disorder. Furthermore, the electronic structures illustrate that the magnetic moments sharply decrease with an increase in the B-site antisite defects, i.e., the total magnetic moments obviously reduce with an increase in the B-site Fe/Nb disorder, and ultimately, no magnetism is observed. Interestingly, the B-site antisite defects not only introduce Fe-Fe antiferromagnetic coupling, but also induce the antiferromagnetic arrangement of Cu spins in the totally disordered structure. Cu-Fe and Fe-Fe magnetic coupling competition is coupled with antisite defects, and finally, Fe-Fe antiferromagnetic coupling turns into the dominating spin coupling in the disordered CaCu3Fe2Nb2O12. Moreover, the B-site antisite defects do not alter the insulator nature of the perovskite despite the significantly narrowed band gap. Our study opens up a novel avenue for the straightforward understanding of the effect of cationic ordering on the electronic and magnetic properties of quadruple perovskites and offers an additional opportunity for tailoring their characteristics.

The Electrochemical Conversion of Carbon Dioxide on Cu−Ni Stacked Bilayer Electrodes

The product selectivity in the electrochemical conversion of carbon dioxide (CO2) strongly depends on the electrode metal. As each metal leads to a characteristic product composition, a multimetallic composite electrode is required for the selective product formation by CO2 conversion. Here, we show the selective CO2 conversion with a current efficiency of 56.2% for the hydrocarbon formation on the Cu–Ni stacked bilayer electrodes. Interestingly, a thinner Ni stacked electrode shows higher selectivity in converting CO2 to hydrocarbons than pristine Cu electrodes, while no hydrocarbon formation carries out on those with thicker Ni deposition or on pristine Ni electrodes. We also demonstrate that the crystal structure of the support Cu electrode significantly contributes to the activity of CO2 conversion, further confirming the importance of the structural arrangement of Cu and Ni in the Cu–Ni stacked bilayer electrodes.

Site-Specific Adsorption of Aromatic Molecules on a Metal/Metal Oxide Phase Boundary.

Nanostructured surfaces are ideal templates to control the self-assembly of molecular structures toward well-defined functional materials. To understand the initial adsorption process, we have investigated the arrangement and configuration of aromatic hydrocarbon molecules on nanostructured substrates composed of an alternating arrangement of Cu(110) and oxygen-reconstructed stripes. Scanning tunneling microscopy reveals a preferential adsorption of molecules at oxide phase boundaries. Noncontact atomic force microscopy experiments provide a detailed insight into the preferred adsorption site. By combining submolecular resolution imaging with density functional theory calculations, the interaction of the molecule with the phase boundary was elucidated excluding a classical hydrogen bonding. Instead, a complex balance of different interactions is revealed. Our results provide an atomistic picture for the driving forces of the adsorption process. This comprehensive understanding enables developing strategies for the bottom-up growth of functional molecular systems using nanotemplates.

Comparative analysis of graphene grown on copper and nickel sheet by microwave plasma chemical vapor deposition

Microwave plasma chemical vapor deposition (MPCVD) is expected to prepare graphene film at a low temperature and a short growth time. So the same and different process conditions were designed to deposit graphene on Cu and Ni sheets. Despite the atom arrangement of Cu (111) and Ni (111) corresponding to graphene, the different films were obtained at the same process due to the difference in electron configuration of 3d shell of two elements. Carbon atoms penetrated into Ni sheet and segregated to form graphene while graphene film was grown on Cu surface directly. The different growth mechanism resulted in different preparation conditions on substrates where graphene grown on copper sheet preferred mild conditions. It is high energy and large density of microwave plasma that leads to dense surface of substrate and strong etching on graphene film, which is different from chemical vapor deposition (CVD) process.

Bulky bis(imidazole) and 2‐sulfoterephthalate Assisted 3‐D Cu(II) and 2‐D Mn(II) Coordination Polymers: Topology, Diversity in Metal Containing Nodes and Spectral Elucidation

AbstractThis work presents the synthesis of a 3‐D Cu(II) framework represented by a 4,6‐c 2‐nodal net of the type fsc employing the bifunctional template group sulfonate‐carboxylate and the dia precursor (dia=9,10‐di(1H‐imidazol‐1‐yl)anthracene). The high versatility of the N‐donor and carboxylate ligands also yields a 2‐D Mn chain described by a pcu primitive cubic net. The solvent‐dependent EPR studies for both the CPs are also illustrated. Variable temperature magnetic susceptibility confirms that both ferromagnetic and antiferromanetic interactions coexist in 1 among the different geometrical arrangement of Cu(II) ions.

Influence of the Cu Content in Cu2ZnSn(S,Se)4 solar cell absorbers on order-disorder related band gap changes

We investigate the electronic structure and the radiative recombination in wet-chemically fabricated Cu2ZnSn(S,Se)4 solar cell absorbers utilizing photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy, focusing especially on the effects of varying Cu content. This includes the impact of the latter on the band gap energy and the change in band gap energy related to the order-disorder transition. Characteristic PL and PLE parameters like the energetic position of the PL maximum and the PL yield as a function of the excitation power as well as the PLE tailing parameter do not depend on composition indicating that the nature of the radiative transition is not altered by the Cu content. However, the band gap energy Eg significantly increases as a function of decreasing Cu content. This increase is more pronounced in the disordered than in the ordered atomic arrangement of Cu and Zn atoms in the Cu–Zn planes of the kesterite crystal structure.

Spacer-Controlled Supramolecular Assemblies of Cu(II) with Bis(2-Hydroxyphenylimine) Ligands. from Monoligand Complexes to Double-Stranded Helicates and Metallomacrocycles

Reaction of Cu(NO3)2·3H2O or Cu(CH3COO)2·H2O with the bis(2-hydroxyphenylimine) ligands H2L1-H2L4 gave four Cu(II) complexes of composition [Cu2(L1)(NO3)2(H2O)]·MeOH, [Cu2(L2)2], [Cu2(L3)2] and [Cu2(L4)2]·2MeOH. Depending on the spacer unit, the structures are characterized by a dinuclear arrangement of Cu(II) within one ligand (H2L1), by a double-stranded [2+2] helical binding mode (H2L2 and H2L3) and a [2 + 2] metallomacrocycle formation (H2L4). In these complexes, the Cu(II) coordination geometries are quite different, varying between common square planar or square pyramidal arrangements, and rather rare pentagonal bipyramidal and tetrahedral geometries. In addition, solution studies of the complex formation using UV/Vis and ESI-MS as well as solvent extraction are reported.

Copper-incorporated mono- and di-TeRu5 metal carbonyl complexes: syntheses, structures, and an unusual skeletal arrangement.

Two sandwich-type Cu3Cl- or Cu2{Te2Ru4(CO)10}-bridging di-TeRu5 clusters, [{TeRu5(CO)14}2Cu3Cl](2-) () and [{TeRu5(CO)14}2Cu2{Te2Ru4(CO)10}](4-) (), were obtained from the reaction of [TeRu5(CO)14](2-) with 1 equiv. of [Cu(MeCN)4][BF4] in CH2Cl2 or THF at 0 °C, respectively, depending on the solvents. The chloride-abstracted was structurally characterized to have two TeRu5 cores that were linked by a Cu3Cl moiety with two Cu-Cu bonds. If the reaction was carried out in a molar ratio of 1 : 2 at 0 or 30 °C in CH2Cl2, the structural isomers [TeRu5(μ-CO)2(CO)12(CuMeCN)2] () and [TeRu5(μ-CO)3(CO)11Cu2(MeCN)2] () were produced, respectively, as the major product. Cluster displayed a TeRu5 core with two adjacent Ru3 triangles each capped by a μ3-Cu(MeCN) fragment, while contained a TeRu5 core with one triangle Ru3 plane capped by a Cu2(MeCN)2 fragment with two Cu atoms covalently bonded. Upon heating, the isomerization of into proceeded to undergo an unusual skeletal arrangement of Cu(MeCN) and migration of CO, with the TeRu5 core remaining intact. An electrochemical study revealed that and each exhibited only one oxidation while cluster had two consecutive oxidations, suggesting significant electronic communication between the two TeRu5 metal cores in via the Cu3 moiety. This work describes the facile synthesis of a series of semiconducting Cux-bridging Te-Ru carbonyl clusters, in which the incorporation of the Cux fragments has significantly influenced their resulting structures, rearrangements, and electronic properties, which was further elucidated by DFT calculations.

New Three-Dimensional Thiostannates Composed of Linked Cu8S12 Clusters and the First Example of a Mixed-Metal Cu7SnS12 Cluster

Three new compounds (enH)(6+n)Cu(40)Sn(15)S(60) (1), (enH)(3)Cu(7)Sn(4)S(12) (2), and (trenH(3))Cu(7)Sn(4)S(12) (tren = tris(2-aminoethyl)amine) (3) containing Cu(8)S(12) and Cu(7)SnS(12) clusters have been prepared from direct solvothermal reaction of the elements in amine solvents. In 1, the cubic close-packed arrangement of Cu(8)S(12) clusters, interconnected by capping SnS(4) tetrahedra and CuS(3) triangles, form two interpenetrating channel networks that are presumably filled with disordered solvent molecules. Structures 2 and 3 contain well-ordered, protonated amine molecules and Cu(7)SnS(12) clusters. The clusters are connected by SnS(4) tetrahedra to form a three-dimensional structure with ReO(3) topology. (119)Sn Mössbauer measurement is consistent with Sn(IV) atoms linking, and Sn(II) atoms within, the mixed-metal Cu(7)SnS(12) clusters.

An antiferromagnetically coupled trinuclear Cu(II) complex containing μ( O, O′), μ( O) carboxylates and μ( O) phenoxide bridges

The trinuclear complex [L 2Cu 3(CF 3CO 2) 4] ( 1) has been synthesized and its crystal structure determined. It consists of a linear arrangement of Cu(II) centers. The central copper atom is bonded to six oxygen atoms and has a tetragonally distorted octahedral geometry, while the terminal copper atoms are bonded to three oxygen and two nitrogen atoms and show a distorted square pyramidal geometry. The complex shows di-μ( O, O′) syn– syn carboxylate bridging as well as monoatomic (μ-O) bridging, along with phenolate (μ-O) oxygen bridging. Cryomagnetic investigations in the range 2–300 K revealed an antiferromagnetic spin exchange interaction with J = −95.7 cm −1, based on the isotropic exchange model H ex = −2 J[ S 1 · S 2 + S 2 · S 3].

Z-contrast imaging of the arrangement of Cu in precipitates in 6XXX-series aluminium alloys

High-resolution annular dark field imaging has been used to study small precipitates in the Al matrix of 6XXX-series aluminium alloys. Cu-containing columns in precipitates were imaged by atomic number contrast along a ⟨100⟩ matrix direction. At an under-aged condition, large, lath-shaped particles of the Cu-containing Q′-phase were observed at grain boundaries. At over-aged conditions, Q′ was the main matrix phase. In both cases the laths showed an Al {150} habit plane. A precursor phase was found, with different arrangement of Cu-rich columns from that of the Q′-phase and sharing Al {100} habit planes. Precipitates containing elements of both the Q′-phase and the precursor were found to be common. Annular dark field imaging can differentiate directly between phases. The method complements and aids interpretation of conventional high-resolution TEM images and nano beam diffraction observations. The results obtained contribute to an improved understanding of the crystallography of the precursor and details of the structural transformation taking place during the precipitation process.