Copper Precursor Research Articles

Facile and Novel Chemical Synthesis, Characterization, and Formation Mechanism of Copper Sulfide (Cu2S, Cu2S/CuS, CuS) Nanostructures for Increasing the Efficiency of Solar Cells

This paper reports the successful synthesis of various copper sulfide nanostructures via coprecipitation and hydrothermal routes using new starting reagents such as Na2SO3 as a reducing agent for converting Cu2+ to Cu+ and PMP dye–Cu(II) and carminic acid–Cu(II) complexes as new copper precursors for synthesizing quantum dots in aqueous medium. The as-synthesized products were extensively characterized by techniques including XRD, EDS, SEM, TEM, AFM, and DRS. Effects of different parameters such as temperature, surfactant, solvent, concentration, copper precursor, sulfide source, etc., on morphology and particle size of as-synthesized nanostructures were investigated. Moreover, the efficiency of various as-synthesized nanostructures in thin layer solar cells was evaluated. The results showed that particle size and morphology have a salient effect on solar cell efficiency. Also, utilizing prepared Cu2S quantum dots as a barrier layer in dye-sensitized solar cells (DSSCs) presented a remarkable increase in ...

Pt@Cu/C Core-Shell Catalysts for Hydrogen Production Through Catalytic Dehydrogenation of Decalin

Pt@Cu/C core-shell catalysts were successfully prepared by impregnation of a carbon support with copper precursor, followed by transmetallation between platinum and copper. The Pt@Cu/C core-shell catalysts retained a core of copper with a platinum surface. The prepared catalysts were used for hydrogen production through catalytic dehydrogenation of decalin for eventual application to an onboard hydrogen supply system. Pt@Cu/C core-shell catalysts were more efficient at producing hydrogen via decalin dehydrogenation than Pt/C catalysts containing the same amount of platinum. Supported core-shell catalysts utilized platinum highly efficiently, and accordingly, are lower-cost than existing platinum catalysts. The combination of impregnation and transmetallation is a promising approach for preparation of Pt@Cu/C core-shell catalysts.

Homolytic cleavage of the O-Cu(ii) bond: XAFS and EPR spectroscopy evidence for one electron reduction of Cu(ii) to Cu(i).

The investigation into the active copper(i) catalysts from copper(ii) precursors has become a fundamental and important task in copper catalysis. In this work, we demonstrate that the (t)BuO(-) anion serves not only as a base but also as a mediator to promote the reduction of Cu(ii) to Cu(i) in copper catalysis. XAFS and EPR spectroscopy evidence the [Cu(O(t)Bu)3](-) ate complex as the key intermediate which undergoes homolytic-cleavage of the O-Cu(ii) bond generating [Cu(O(t)Bu)2](-) ate complex.

Rheological Study of a Copper Feedstock

MIM technique is described in which allows for the production of highly porous metallic foams with porosity levels up to 90%. It makes use of the pressure built up by the decomposition of a foaming agent which is incorporated in a foamable precursor copper material obtained by powder compaction. A suitable behaviors feedstock that refers to its rheological is one of the key factors to ensure the successful of MIM technique and to predict failure, whether due to the binder component and compositions, powder loading or unsuitable process parameters. Potassium carbonate and polyethylene is added and were mixed homogeneously to form a copper feedstock. The rheological results in term of shear rate, shear stress, viscosity, melting rate and softening temperature which related to pseduoplastic behaviors have been conducted using a capillary rheometer (CFT-500D, Shimadzu) at various temperature and loads. The result has indicated that the viscosity of the feedstock is decreased with increasing shear rate thus proved the feedstock to be pseudoplastic.

Analysis of the Rheological Behavior of Copper Metal Injection Molding (MIM) Feedstock

Metal Injection Molding (MIM) technique allows for the production of highly porous metallic foams with porosity levels up to 90%. It makes use of the pressure built up by the decomposition of a foaming agent which is incorporated in a foamable precursor copper material obtained by powder compaction. Rheological is one of the key factors to ensure the successful of MIM technique and to predict failure, whether due to the binder component and compositions, powder loading or unsuitable process parameters. The balanced ratio feedstock contains of 63 vol.% of copper powder, different percentage of potassium carbonate; Batch 1 (0.4 vol.%), Batch 2 (0.5 vol.%) and Batch 3 (0.6 vol.%), and the remaining volume percentage of binder system has been mixed to form copper feedstock. The rheological behaviors were investigated using a capillary rheometer (CFT-500D, Shimadzu) at various temperature and loads. From the experiments, it was concluded that the MIM feedstock exhibit a shear thinning or pseudo-plastic behavior based on the trend of graph which is suitable for MIM process. This result is within the ideal range of viscosity theoretical for MIM feedstock which is in the range of between 10Pa.s to 1000Pa.s at all temperature tested. The viscosity of a pseudo-plastic substance decreases as the shear rate increases (shear thinning). This could be due to particle orientation and ordering with flow as well as breakage of particle agglomerates released together with the binder.

Atomic layer deposited p-type copper oxide thin films and the associated thin film transistor properties

Copper oxide (CuOx) films were grown at a relatively low temperature (100°C) by atomic layer deposition (ALD). Hexafluoroacetyl-acetonateCu(I)(3,3-Dimethyl-1-butene) ((hfac)Cu-(I)(DMB)) and ozone (O3) were used as the copper precursor and oxidant, respectively. It is shown that stable phases of CuOx are obtained through rapid thermal annealing (RTA) in air. After annealing at various temperatures (200–500°C), different p-type band structures and electron binding information are obtained. X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) studies indicate that the major copper oxidation state changes from 1+ to 2+ during thermal treatment. Thin film transistors (TFTs) incorporating the ALD-grown CuOx semiconductors are evaluated, and an unusually high p-type device performance is observed, with a field effect mobility of 5.6cm2/Vs after annealing at 300°C.

Comparative Synthesis of Cu and Cu2O Nanoparticles from Different Copper Precursors in an Ionic Liquid or Propylene Carbonate

AbstractCopper metal and copper(I) oxide (cuprite, cuprous oxide) nanoparticles (Cu‐NPs and Cu2O‐NPs) were prepared from different readily available copper salts by means of microwave irradiation in propylene carbonate (PC) or in the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF4]) without addition of extra reducing agents. The nanostructures were studied by high‐angle annular dark field‐scanning transmission electron microscopy, TEM, SEM, and powder XRD. Star‐shaped agglomerated Cu‐NPs with about 45 nm diameter were formed from Cu(BF4)2 in PC. Cu‐NPs with smaller size distributions of 3.1 ± 0.7 nm and 3.7 ± 1.4 nm were obtained when copper(II) bis[1‐(dimethylamino)propan‐2‐olate], Cu[OCH(Me)CH2NMe2]2, was decomposed in PC and in [BMIm][BF4]. Small Cu‐NPs were also obtained from copper(II) acetylacetonate in [BMIm][BF4] with a diameter distribution of 3.3 ± 0.9 nm. Cubic Cu2O nanocubes (Cu2O‐NCs) of 43 ± 15 nm in size could be prepared by using Cu(OAc)2·H2O with [BMIm][BF4]. The size of the Cu2O‐NCs increased on isolation from the neat IL by addition of acetonitrile, which gave NCs of 0.1–0.5 μm in size.

Effect of copper precursor on simultaneous removal of PM and NOx of a 2-way SCR/CDPF

The purpose of this study is to analyze the effect of Cu-precursors for a Selective Catalytic Reduction (SCR) catalyst on the de-NOx and de-PM performance of a 2-way SCR/DPF. For the SCR catalyst in the Diesel Particulate Filter (DPF) substrate, beta zeolite (BEA) was used as the catalyst support and Cu as the main catalyst. In this case, copper (II) sulfate and copper (II) chloride were used as the Cu-precursors. A model gas reactor was used to evaluate the performance of the catalyst, and Fourier Transform Infrared (FTIR) spectrometry was used to analyze the concentrations of nitrogen oxides (NOx), ammonia NH3, and other gases. The result from one experiment indicated that the NOx conversion of the fresh CuSO4–BEA catalyst was similar to that of the fresh CuCl2–BEA catalyst. However, after hydrothermal aging, the NOx conversion of the CuCl2–BEA catalyst was much higher than that of the CuSO4–BEA catalyst. These findings indicate that the CuCl2–BEA catalyst had outstanding durability, which was analyzed to verify the structure of the catalyst and its chemical changes. Varieties of ion-exchanged copper types were observed in the zeolite catalyst support, implying that the activation of the catalyst was mainly due to copper. The CuCl2–BEA catalyst also showed superior PM oxidation performance compared to the other SCR/DPF catalysts.

The Interfacial Reaction at ITO Back Contact in Kesterite CZTSSe Bifacial Solar Cells

The synthesis route based on co-electroplating of copper, zinc, tin, and chalcogen precursor plus post-chalcogenization demonstrates the tremendous potential to realize industrial manufacture of earth-abundant kesterite materials for sustainable photovoltaics. Exploration of appropriate annealing temperature is significant to gain insight into the crystallization of kesterite solar materials on the back contacts based on transparent conducting oxides in bifacial device. The Cu2ZnSn(Sx, Se1–x)4 (CZTSSe) absorber films have been fabricated by post-selenizing co-electroplated metal–sulfide precursors on ITO substrate at 500, 525, and 550 °C. Experimental proof, including electron microscopies, X-ray diffraction, optical transmission/reflection spectra, polarized Raman, and IR techniques, is presented for the interfacial reaction between the ITO back contact and CZTSSe absorber. This reaction contributes to substitutional diffusion of In into CZTSSe (CZTISSe) to a considerable extent and formation of a SnO2 interfacial layer when the temperature is higher than 500 °C. In incorporation does not much change the optical absorption, band gap, and phonon spectra of CZTSSe; whereas, it leads to lattice expansion more or less. The bifacial kesterite solar devices are successfully fabricated, and the device performance is analyzed and discussed.

Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation

Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application.

Conversion of commercial Pt/C to “clean” Pt-Cu/C catalyst with high activity toward methanol oxidation

ABSTRACT A green synthetic strategy is developed to prepare Pt x Cu y /C catalyst in the absence of any capping ligands. Commercial Pt/C catalyst is used as the platinum precursor, and the Pt nanoparticles on the carbon act as a catalyst for the reduction of copper (II) precursors by hydrazine, which leads to the confined deposition of Cu on the Pt nanoparticles. The newly deposited Cu diffuses into the Pt nanoparticles to form Pt x Cu y alloy nanoparticles under hydrothermal conditions. The as-synthesized Pt x Cu y /C exhibits superior activity compared with commercial Pt/C towards the electro-oxidation of methanol. The results highlight the significance of alloy formation as an approach to improve the activity of commercial Pt/C catalyst.

Silica aerogel-supported copper catalyst prepared via ambient pressure drying process

Copper–silica aerogel catalyst was synthesized through the impregnation of silica alcogels by copper precursor and ambient pressure drying of the impregnated alcogels. In this safer and lower energy consumption drying mode for maintaining the gel structure, the solvent exchange and chemical surface modification were done before the drying step. The prepared Cu/SiO2 aerogels were characterized by AAS, XRD, FE-SEM, EDX, TEM, FTIR, BET and BJH techniques. Characterizations showed the complete surface modification, the presence of CuO nanocrystals, the relatively uniform dispersion of copper, the catalysts consisted of the nanoparticles, the homogeneous surface morphology, the large surface area (511–652 m2/g) and the high pore volume (~2.7 cm3 g) and mesoporosity which are the attractive properties of aerogels as catalyst. Also, the activity and selectivity of aerogel catalysts were studied in the hydrogen production process through methanol steam reforming reaction which showed good results.

Printing a Self‐Reducing Copper Precursor on 2D and 3D Objects to Yield Copper Patterns with 50% Copper's Bulk Conductivity

Printing a Self‐Reducing Copper Precursor on 2D and 3D Objects to Yield Copper Patterns with 50% Copper's Bulk Conductivity

Formation of homogenous copper film on MWCNTs by an efficient electroless deposition process

Abstract In this study, copper-coated multi-walled carbon nanotubes (MWCNTs) were prepared using electroless deposition process with an efficient bath composition. As-received MWCNTs underwent acid treatment and subsequent sensitization with tin and activation with palladium before the copper coating process. The electroless deposition process was performed in a bath, which contained copper sulphate pentahydrate as a copper precursor, potassium sodium tartrate as a complexing agent, and formaldehyde as a reducing agent. Surface modifications of MWCNTs were studied by Fourier transform infrared spectroscopy, imaging techniques (scanning electron microscopy, transmission electron microscopy), and X-ray diffraction. On the basis of the results, it was observed that the coating layer covers most surfaces of the nanotubes. Furthermore, copper oxide is also deposited on the surfaces of MWCNTs. The total amount of metals after each sensitization, activation, and metallization step was determined by thermo gravimetric method and induced coupled plasma atomic emission spectroscopy. Coating of MWCNTs was accomplished successfully through adjusting proper chemical ratios and concentrations. The calculated bath efficiency was about 99%.

Monodisperse Copper Chalcogenide Nanocrystals: Controllable Synthesis and the Pinning of Plasmonic Resonance Absorption.

Controllable synthesis of copper chalcogenide nanocrystals (NCs), including desired geometry, composition and surrounding environment, is of high significance for the modulation of their optoelectronic response and the corresponding applications. Herein, copper nitride nanoparticles have been used as "uncontaminated" copper precursors to synthesize copper chalcogenide NCs with high monodispersity through a one-pot strategy. In this protocol, the sizes and compositions of NCs can be readily controlled by varying the ratio of the precursors. For Cu(2-x)S NCs with different diameters, the size variations are all smaller than 5.6%. Furthermore, the plasmonic properties of the copper chalcogenide NCs are investigated under a steady state by tuning the plasmonic resonance absorption band to a limiting condition (denoted "pinning" phenomena). It is observed that the pinning frequency increases (from 1.09 to 1.23 eV) with the increment of the NC size (from 5.4 ± 0.3 to 11.1 ± 0.4 nm), explained by introducing surface scattering. Meanwhile, the frequencies of ternary alloyed copper sulfide selenide NCs blue-shift from 0.90 to 1.00 eV with the increase of selenium content from 11% to 66%, which is related to the effective mass of free carriers. Additionally, the plasmonic absorption bands of Cu(2-x)S NCs encapsulated by two single-layer graphene pin at 1525-1550 nm during the oxidation process, which is influenced by both the dielectric constant and redox potential of the surrounding environment. This study demonstrates the controllable synthesis and precise fundamental plasmonic properties of the copper chalcogenide NCs, ensuring the potential plasmonic-related techniques with high efficiency, accuracy and excellent spatial resolution.

Solvothermal fabrication and enhanced visible light photocatalytic activity of Cu2O-reduced graphene oxide composite microspheres for photodegradation of Rhodamine B

The addition of graphene oxide (GO) in the semiconductors has been regarded as one of the effective methods to enhance their photocatalytic activity. In this study, Cu2O-reduced graphene oxide (Cu2O-rGO) composites with low loading (0–0.5wt.%) of graphene oxide (GO) were produced by a one-step green solvothermal method in ethanol system by using Cu(NO3)2·3H2O and glutamic acid as copper precursor and reducing agent, respectively. During the solvothermal treatment, GO was reduced to rGO. The as-prepared Cu2O-reduced graphene oxide composite microspheres exhibited enhanced photocatalytic activity toward the degradation of RhB aqueous solution under visible light irradiation. At the optimal loading of graphene oxide (0.05wt.%), Cu2O-rGO composites showed the highest photocatalytic activity, exceeding that of pure Cu2O and commercial Degussa P25 by a factor of 2.9 and 7.9, respectively. The enhanced photocatalytic activity may be ascribed to the strong coupling interaction between Cu2O particles and rGO nanosheets, which reduces the recombination of charge carriers.

Microstructure and electrical property of copper films on a flexible substrate formed by an organic ink with 9.6 % of Cu content

An organic copper ink with 9.6 wt% of Cu content derived from a short carbon chain organic copper precursor was successfully applied on a modified PI substrate and easily formed a favorable conductive copper film by self-reduction in the sintering process, which showed excellent conductivity. The effects of sintering temperature and time on the microstructure and conductivity action of the copper films were studied by XRD, EDS and SEM and electrical measurements, respectively. The sheet resistance and resistivity were determined to be as low as 0.11 Ω/□ and 2.2 × 10−5 Ω·cm. The conduction mechanism is discussed in terms of the percolation theory.

Simulation and modeling of synthesis Cu nanoparticles in sodium alginate media by means of expert systems

This research was to apply the combination of the particle swarm optimization method and artificial neural network training with the aim of building a quantitative model to forecast the size of copper nanoparticles (Cu-NPs) prepared in sodium alginate. Sodium alginate, sodium hydroxide, copper sulfate, hydrazinium hydroxide, and ascorbic acid were used as stabilizer, pH moderator, copper precursor, reducing agent, and antioxidant, respectively. The results showed that the different sizes of Cu-NPs were obtained by changing these functions. Meaning that by increasing the amount of sodium alginate and or increase the volume of hydrazine hydrate, particle sizes of Cu-NPs were reduced. Other variables had the opposite effects due to the increase of the size of the Cu-NPs. The prediction results were remarkably in agreement with the experimental data with a correlation coefficient of 0.99 and a mean square error of 0.0058.

MOF derived porous carbon supported Cu/Cu2O composite as high performance non-noble catalyst

Porous carbon supported copper composite (Cu/Cu2O/C) was synthesized with a facile, low cost and novel method and used as non-noble-metal catalyst for reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4. In the synthetic strategy, metal organic framework Cu3(BTC)2 (also denoted as HKUST-1) was used as both sacrificial template and copper precursor, and phenol formaldehyde resin as carbon precursor. The catalytic Cu/Cu2O nanoparticles (Cu/Cu2O NPs) about 40 nm-in-diameter distributed uniformly both on the internal and external surface of the porous carbon flakes, and took up 33.38–37.56 wt% of the Cu/Cu2O/C composite. Compared with noble metal catalysts, the prepared composite showed comparable high catalytic activity, which was mainly due to their porous structure facilitating diffusion of reactants and products, and the high dispersion of accessible catalytic Cu/Cu2O NPs on porous carbon. Moreover, the synthesized catalyst can be reused for at least five cycles due to its good stability. These results confirmed that the as-prepared Cu/Cu2O/C is promising candidate to replace noble metal for catalytic application.

Carbon supported Pd–Cu catalysts for highly selective rearrangement of furfural to cyclopentanone

The aqueous phase hydrogenation of furfural to cyclopentanone was investigated using carbon supported Pd–Cu catalysts prepared by various methods. The most active and selective Pd–Cu catalysts were obtained using electroless plating procedure of deposition of copper in the presence of tartrate carboxylate ligands. It is an alternative and promising way to deposit metal nanoparticles onto the surfaces of porous solid supports. As the XRD data revealed in these catalysts beside metallic palladium with the particle sizes 6.8nm the copper exist mainly in Cu+ oxidation state as Cu2O and the metallic copper is practically absent. The selectivity to cyclopentanone was enhanced gradually by the addition of 3, 5 and 10wt% of copper precursor on the pre-reduced 5%Pd/C catalyst. An appropriate Pd0 and Cu+ distribution is presumed to be a key in gaining excellent catalytic activity. Under reaction conditions where mass-transfer effects were eliminated the furfural conversion about 98% and cyclopentanone yield 92.1mol% were achieved using only 1wt% concentration of 5%Pd–10%Cu/C catalyst and reaction time 1h. According to the proposed mechanism the dominant parameters responsible for reaching very high selectivity of cyclopentanone are (i) very high yield of primary formed furfuryl alcohol and (ii) higher rate of its subsequent conversion to cyclopentanone via the pathway not involving 4-hydroxy-2-cyclopentenone as the main intermediate.