Copper Loading Research Articles

Silica-Supported Copper (II) Oxide Cluster via Ball Milling Method for Catalytic Combustion of Ethyl Acetate

Highly dispersed CuO/SiO2 catalysts were successfully synthesized by a green process of ball milling (BM) under solvent-free and room temperature conditions. The structural evolution of CuO/SiO2 catalysts prepared by BM was elucidated by TG-DSC, XRD, FT-IR, and XPS characterizations. We found that the copper acetate precursor was dispersed over the layer of copper phyllosilicate which was formed by reacting between the copper acetate precursor and the silica support during the BM process. The copper phyllosilicate layer over the support might play an important role in the stabilization of the CuO cluster (<2 nm) during thermal pretreatment. The 15% CuO/SiO2 catalyst exhibited the best catalytic activity for the catalytic combustion of ethyl acetate as it owned a highest active surface area of CuO among the CuO/SiO2 catalysts with different copper loadings.

Modulating the Active Sites of Oxygen-Deficient TiO2 by Copper Loading for Enhanced Electrocatalytic Nitrogen Reduction to Ammonia.

The electrocatalytic nitrogen reduction reaction (NRR) provides a sustainable route for NH3 synthesis. However, the process is plagued by the strong NN triple bond and high reaction barrier. Modification of catalyst surface to increase N2 adsorption and activation is crucial. Herein, copper nanoparticles are loaded on the oxygen-deficient TiO2 , which exhibits an enhanced NRR performance with NH3 yield of 13.6µg mgcat -1 h-1 at -0.5V versus reversible hydrogen electrode (RHE) and Faradaic efficiency of 17.9% at -0.4V versus RHE compared to the pristine TiO2 . The enhanced performance is ascribed to the higher electrochemically active surface area, promoted electron transfer, and increased electron density originated from the strong metal-support interaction (SMSI) between Cu nanoparticles and oxygen-deficient TiO2 . The SMSI effect also results in lopsided local charge distribution, which polarizes the adsorbed N2 molecules for better activation. This work provides a facile strategy toward the electrocatalyst design for efficient NRR under ambient conditions.

Modeling the Distribution of Copper Loading Using Water Quality Modeling and its Impact Factor Analysis

In this study, to trace the influence of copper pollution sources on sediments, the copper distribution in Lijiang River was studied with water quality model tools. In addition, the effects of velocity, sources, and hardness on the characteristic parameters of copper were investigated.

Fabrication of ultrafine sporopollenin particles and its application as pesticide carrier

Control release formulation is of great interest to pesticide researchers due to its programmable release of active ingredients with low environmental risk. The carrier is a dominant factor affecting the performance of the preparation. In this work, a copper-based fungicide is developed using plant sporopollenin materials as a control release carrier. Although sporopollenin is regarded as the toughest natural material, sporopollenin was broken down into nano- and micro- particles along with the modified surface chemistry by a facile oxidation treatment. The surface chemistry of sporopollenin is characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS) and Boehm titration. The resulting ultrafine sporopollenin particles (USPs) show a high copper(II) loading capacity of 435 mg/g, owing to the electrostatic effect. Furthermore, copper(II) can be released from copper(II)–sporopollenin complex (Cu-USPs) in a pH-dependent manner. As a proof of concept, Cu-USPs show very promising activity against a plant-specific pathogen-Pectobacterium carotovorum. Overall, this paper shed light on developing sporopollenin-derived functional materials for pesticide delivery.

Facilely coupling CaTiO3 nanorods with Cu nanoparticles for enhanced photocatalytic hydrogen evolution through efficient charge separation

Photocatalytically splitting water to hydrogen production is a great potential for addressing the issue of energy crisis and environmental pollution. Metal-semiconductor hybrid photocatalyst has attracted increasing attention, and especially non-noble metal decoration is one of promising strategies to promote photoinduced electron-hole pairs separation for an efficient solar-to-hydrogen evolution. Herein, a facile solvothermal approach was successfully employed to prepare calcium titanate (CaTiO3) nanorods with decoration of copper particles. The composition and morphology characterization showed that the Cu particle was deposited on the surface of CaTiO3 nanorod. The as-synthesized CaTiO3/Cu composites exhibited promoted solar-to-hydrogen performance and their activities varied from copper loading amounts. The optimized CaTiO3/Cu-0.05 achieved a hydrogen evolution rate of 251 µmol g−1 h−1 , which was much higher than that of bare CaTiO3. Based on the photoluminescence spectra and photocurrent density measurements, it was proposed that efficient separation of photogenerated charges was achieved between the CaTiO3 nanorod and Cu nanoparticles, which promoted water splitting for H2 production. This work further confirms that metallic Cu decoration is an efficient approach to promote photocatalytic H2 production performance of semiconductor photocatalysts.

Mechanics of thin film coated Bulk Metallic Glass composites

Bulk Metallic Glasses (BMGs) exhibit superior mechanical properties such as high strength (≈2 GPa), high yield strain (≈2%) and high corrosion resistance. But, they lack ductility which prevents them from being used as structural materials. One of the methods explored by material scientists to improve their strain to failure is to coat BMGs with a thin layer of a ductile polycrystalline metal such as Copper. In this work, we numerically investigate the mechanical behavior of thin film coated BMGs through Finite Element (FE) Simulations. We simulate the effect of an extrinsic copper coating on the deformation and failure of monolithic BMG cylinders under uniaxial loading. We employ the Anand and Su (2005) constitutive model for BMGs implemented by us in ABAQUS FE software via user material subroutines: UMAT and VUMAT. An isotropic, elastoplastic material model is used for representing the Copper coating with properties of pure Copper. Three-dimensional, two-dimensional plane strain and axisymmetric simulations of uniaxial loading of monolithic BMG and Copper coated BMG composite at quasi-static strain-rate are performed using the Explicit/Dynamics formulation in ABAQUS. The simulations take into consideration a ductile damage and failure mechanism involving cracking inside the shear bands in the BMG matrix. We observe the formation of shear bands which transform into cracks in the BMG matrix. The simulations are able to correctly predict the deformation and fracture mechanism of the BMG matrix and copper coating under uniaxial loading. Results show that a thin copper coating of about 1–5% of the diametrical thickness of the cylinder increases the strain to failure of the coated BMG composite by about 2% which is in qualitative agreement with experimental observations reported in literature. The present results have implications for designing coated BMGs with improved malleability or strain to failure enabling their deployment in structural applications.

A mesoporous metal-organic framework used to sustainably release copper(ii) into reducing aqueous media to promote the CuAAC click reaction.

The mesoporous metal-organic framework Cr-MIL-101-NH2 (MOF1) has been used to encapsulate, by a simple impregnation method, large amounts of copper sulfate. The resulting loaded material, Cu@MOF1, was successfully employed to slowly release copper(ii) into an appropriate reaction medium in which the reducing agent sodium ascorbate reduces copper(ii) to copper(i), thus allowing the well-known copper(i)-catalyzed alkyne-azide cycloaddition (CuAAC) "click" reaction to proceed in the absence of potentially high local copper(i) concentrations. The use of a MOF-based controlled copper release system such as Cu@MOF1 may be relevant for copper(i)-catalyzed reactions having substrates that could be degraded by potentially high local concentrations of copper(i). The copper chelating ligand TBTA (tris(benzyltriazolylmethyl)amine), a very useful ligand for click chemistry, has been successfully attached to the pores of MOF1. The resulting TBTA-functionalized MOF (MOF3) was compared with its non-functionalized version (MOF1). At copper loadings of ca. 3 mmol g-1, the results revealed that the performances of the two materials are strikingly similar. Upon immersion in methanol/water (95/5) containing sodium ascorbate, both materials slowly released copper encapsulated in their pores and could be recovered and reused efficiently for up to five reaction cycles without reloading with metal ion, while allowing the CuAAC reaction to proceed with excellent conversion rates and yields.

Spall and recompression processes with double shock loading of polycrystalline copper

Spall fracture induced by interaction of multiple shockwaves in shock-loaded material is a key issue for both basic science and practical application. Here, shock induced spall and subsequent recompression process of polycrystalline copper are investigated using molecular dynamics simulations. Two significant velocity peaks are observed from the velocity history of free surface, which is explained through the complex propagation of waves and dynamic damage processes. The overshoot feature is also noted in the free-surface velocities on account of the shock response of the damaged region. Recrystallization occurs after secondary shock passes through the spall region. Meanwhile, the differences in recrystallization processes are observed for the different shock response states of the spall region induced by secondary shock waves. What's more, the reduction of grain sizes in the spall region is also revealed in our simulation, which is consistent with experiments.

Synthesis and application of SBA-15-supported CuO as an efficient catalyst for the oxidative C(sp2)-O coupling reaction

SBA-15-supported CuO was synthesized via wet impregnation of SBA-15 with copper (II) acetylacetonate followed by calcination in the static air. The BET surface area of the Cu-containing SBA-15 was approximately 600 m2/g, which significantly decreased in comparison with that of as-synthesized SBA-15 silica (1081 m2/g). The successful loading of copper with a 3.20 wt.% content was determined by ICP-OES analysis, consistent with theoretical composition. However, no Cu-based phases were detected on the PXRD results and TEM images for CuO/SBA-15 showed regular hexagonal meso channels remained, indicating that CuO species was well distributed in the SBA-15 framework via the applied synthetic procedure. Catalytic activity of SBA-15-supported CuO was investigated for the selective C(sp2)-O coupling reaction between salicylaldehyde and N, N-dimethylformamide (DMF) in the presence of di-tert butyl peroxide (DTBP) as an oxidant. Influence of the reaction conditions on the formation of desired product was studied including reaction time, temperature, reactant ratio, amount of catalyst and oxidant. The experimental results proved that the high activity of the prepared catalyst as the C(sp2)-O coupling product could be obtained in an excellent yield of 90% with only 3 mol% of SBA-15-supported CuO in the presence of 4 equivalents of DTBP at 120 °C in 2 hours.

Ce-doping CuO/HZSM-5 as a regenerable sorbent for Adsorption–Oxidation removal of PH3 at low temperature

• Ce-doping Cu/HZSM-5 sorbents were synthesized and used for the removal of PH 3 . • Ce-doping can significantly enhance the adsorption capacity of the Cu/HZSM-5 sorbent. • The interaction between Ce and CuO improves the sorbent physicochemical properties. • The formation of phosphate/phosphide species resulted in the deactivation of sorbent. • The PH 3 capacity was preserved after three times thermal regeneration. A series Ce m Cu n O x /HZSM-5 sorbents were introduced to remove PH 3 in low-temperature and low-oxygen environments. The effects of copper loading and cerium doping on the adsorption–oxidation performance of the sorbents were investigated. Experimental results showed that doping with 1 wt% of cerium (Ce 1 Cu 30 O X /HZSM-5) could significantly improve the performance of the sorbent. The PH 3 breakthrough capacity was identified as 114.36 mg(PH 3 )•g sorbent -1 . In addition, after three thermal regeneration cycles, the sorbent still has ideal performance. X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) analyses exhibited that CuO was the main active species, and Ce-doping can increase the chemisorption oxygen on the surface of the sorbent. BET results demonstrated that the introduction of cerium could improve the specific surface area and pore volume of sorbent. Hydrogen temperature-programmed reduction (H 2 -TPR) and scanning electron microscope (SEM-EDS) indicated that cerium species played an important role in uniformly dispersing copper species on the HZSM-5 surface and improving the oxidation performance of sorbent. Moreover, the reaction products and mechanisms were also investigated by XRD, XPS, and in-situ FTIR spectra. The results indicated that the consumption of CuO and the accumulation of phosphorus species (e.g., P, P 2 O 5 , and Cu 3 P) on the surface and inner pores of the sorbent were the primary reasons for the deactivation of the sorbent.

Oxygen Isotope Exchange over Copper-Containing Mordenite: The Effect of Copper Loading and Si/Al Ratio

Oxygen Isotope Exchange over Copper-Containing Mordenite: The Effect of Copper Loading and Si/Al Ratio

Cu-TiO2/SiO2 photocatalysts for concrete-based building materials: Self-cleaning and air de-pollution performance

As a consequence of human activities, today, we are exposed to high pollution levels that cause building materials damage and many diseases. The application of TiO2 as coating on building materials has proven the efficiency of self-cleaning and air de-pollution. However, its performance is limited due to its absorption being exclusively located at UV light. In this study, Cu-TiO2 photocatalysts were integrated into silica sol–gel synthesis to manufacture new long-lasting term coatings with self-cleaning and air purification properties for concrete-based building materials. The enhancement of TiO2 photoactivity by incorporating Cu into its network has been clearly demonstrated. The self-cleaning and air de-polluting efficiency were assessed using methylene blue (MB), soot and NO, respectively, indicating that the presence of Cu promotes the TiO2 performance. For low doping levels, by increasing the copper loading, the TiO2 photoactivity increased. The highest efficiency was obtained by the photocatalyst containing 5% copper, which shows maximum destruction of methylene blue and soot of 95% and 50% within 60 min and 168 h of irradiation, respectively. However, higher copper loading led to a decrease in its performance, reaching a total degradation of MB and soot of 90% and 45% after 60 min and 168 h of irradiation, respectively, for the sample containing 15% of copper loading.

CuO Quantum Dots Supported by SrTiO3 Perovskite Using the Flame Spray Pyrolysis Method: Enhanced Activity and Excellent Thermal Resistance for Catalytic Combustion of CO and CH4.

As a non-noble-metal catalyst, CuO has great potential in the catalytic combustion of CO and CH4. In this work, the influence of loading active copper components onto perovskites and essential operating parameters in flame aerosol synthesis has been experimentally and theoretically investigated to optimize the catalytic efficiency for the complete oxidation of lean CO and CH4. Herein, the CuO-SrTiO3 nanocatalysts are one-step-synthesized by flame spray pyrolysis with varied copper loadings and precursor feeding rates. The sample under the precursor flow rate of 3 mL/min and the CuO loading of 15 mol % demonstrates optimal catalytic performance. It is primarily attributed to the excellent low-temperature reducibility and improved activity of copper species originated by CuO quantum dots and metal-support interaction. Besides, SrTiO3 perovskite as a support can effectively inhibit the sintering of CuO quantum dots at high temperatures, which is responsible for the excellent sintering and water deactivation resistances.

Removal of elemental mercury from flue gas using the magnetic attapulgite by Mn-Cu oxides modification.

Mercury pollution has become one of the most concerned environmental issues in the world because of its high toxicity, non-degradability, and bioaccumulation. Attapulgite adsorbents modified by magnetic manganese-copper (MnxCuy-MATP) were fabricated by co-precipitation and ultrasonic impregnation method, aiming at removing Hg0 from coal-fired flue gas. BET, SEM, XRD, VSM, and XPS were used to systematically explore the physical and chemical properties of the adsorbents, the effects of manganese and copper additions, reaction temperature, and various components in the flue gas on the efficiency of Hg0 removal were investigated. Mn8Cu5-MATP exhibited the optimal properties, and excessive copper loadings led to the aggregation of the active components. The efficiency of mercury removal can be effectively improved by NO and HCl regardless of the absence and presence of O2, because the NO+, NO3, NO2, and Cl* produced during the reaction can promote the adsorption and oxidation of Hg0. SO2 and H2O inhibited the oxidation of Hg0 because of the competitive adsorption at the active sites, while a large amount of sulfite and sulfate were formed to block the pores. However, the introduction of copper caused the sample to obtain SO2 resistance, which resulted in a mercury removal efficiency of 84.3% even under 1500 ppm SO2. In addition, after 5 cycles of adsorption and regeneration, Mn8Cu5-MATP can still maintain excellent Hg0 removal ability. The fabricated adsorbent can save the actual production cost and effectively improve the mercury removal efficiency in sulfur-containing flue gas.

Catalytic Oxidation of CO and Benzene over Metal Nanoparticles Loaded on Hierarchical MFI Zeolite.

In order to obtain highly active catalytic materials for oxidation of carbon monoxide and volatile organic compounds (VOCs), monometallic platinum, copper, and palladium catalysts were prepared by using of two types of ZSM-5 zeolite as supports—parent ZSM-5 and the same one treated by HF and NH4F buffer solution. The catalyst samples, obtained by loading of platinum, palladium, and copper on ZSM-5 zeolite treated using HF and NH4F buffer solution, were more active in the reaction of CO and benzene oxidation compared with catalyst samples containing untreated zeolite. The presence of secondary mesoporosity played a positive role in increasing the catalytic activity due to improved reactant diffusion. The only exception was the copper catalysts in the reaction of CO oxidation, in which case the catalyst, based on untreated ZSM-5 zeolite, was more active. In this specific case, the key role is played by the oxidative state of copper species loaded on the ZSM-5 zeolites.

Effect of Ni, La, and Ce Oxides on a Cu/Al2O3 Catalyst with Low Copper Loading for Ethanol Non‐oxidative Dehydrogenation

AbstractThe effect of modifying additives (Ni, La, Ce oxides) on the activity of Cu/Al2O3 with a low copper loading was studied for ethanol non‐oxidative dehydrogenation. The catalysts were prepared by impregnation of the commercial Al2O3 granules and characterized by Brunauer‐Emmett‐Teller (BET), scanning electron microscopy (SEM), temperature‐programmed desorption of NH3 (TPD‐NH3), temperature‐programmed reduction of H2 (H2‐TPR), and thermogravimetric analysis (TGA). Modification of Cu/Al2O3 with Ni, La, and Ce oxides results in increasing catalytic activity. A modification of the Cu/Al2O3 catalyst with nickel and lanthanum oxides, in contrast to cerium oxide, leads to an improvement in the dispersion of the catalyst particles. The Cu‐Ni/Al2O3 catalyst with the highest acidity has the highest selectivity for acetaldehyde. The highest selectivity for butanol is observed for the Cu‐La/Al2O3 catalyst, which has the lowest acidity.

The Role of Copper in the Regulation of Ferroportin Expression in Macrophages.

The critical function of ferroportin (Fpn) in maintaining iron homeostasis requires complex and multilevel control of its expression. Besides iron-dependent cellular and systemic control of Fpn expression, other metals also seem to be involved in regulating the Fpn gene. Here, we found that copper loading significantly enhanced Fpn transcription in an Nrf2-dependent manner in primary bone-marrow-derived macrophages (BMDMs). However, prolonged copper loading resulted in decreased Fpn protein abundance. Moreover, CuCl2 treatment induced Fpn expression in RAW 264.7 macrophages at both the mRNA and protein level. These data suggest that cell-type-specific regulations have an impact on Fpn protein stability after copper loading. Transcriptional suppression of Fpn after lipopolysaccharide (LPS) treatment contributes to increased iron storage inside macrophages and may result in anemia of inflammation. Here, we observed that in both primary BMDMs and RAW 264.7 macrophages, LPS treatment significantly decreased Fpn mRNA levels, but concomitant CuCl2 stimulation counteracted the transcriptional suppression of Fpn and restored its expression to the control level. Overall, we show that copper loading significantly enhances Fpn transcription in macrophages, while Fpn protein abundance in response to CuCl2 treatment, depending on macrophage type and factors specific to the macrophage population, can influence Fpn regulation in response to copper loading.

Photothermocatalytic Removal of CO and Formaldehyde with Excellent Water Vapor Stability over Dual‐Functional Copper Loading on TiO2 Synthesized via Flame Spray Pyrolysis

Photothermocatalytic (PTC) oxidation is a high‐efficient, low‐temperature, and green approach to eliminate the air pollutant, but its application is drastically restricted by lack of low‐cost, active, and superior water‐resistance catalysts. Herein, the influence of bifunctional copper components on TiO2 is experimentally and theoretically investigated to optimize PTC efficiency for the CO and HCHO oxidation via flame spray pyrolysis. Both the abundant lattice doping and highly dispersed nanocluster modification of hybrid CuO x remarkably enhance charge separation, maintain a dynamic Cu+/Cu2+ balance, and decrease oxygen vacancy formation energy. The satisfactory PTC CO and HCHO oxidation on the CuO x −TiO2 samples is mainly attributed to higher lattice oxygen activity and less reaction intermediates under irradiation. In addition, the essential synthesis parameters, such as the increasing precursor flux, are assessed to further enhance the PTC performance. Interestingly, photocatalysis effectively removes the surface H2O or hydroxyl group of catalysts, which is responsible for the excellent water vapor stability in the lean CO PTC oxidation.

Removal of Isopropanol by synergistic non-thermal plasma and photocatalyst

The dielectric barrier discharge (DBD) of non-thermal plasmas was combined with a self-made photocatalyst to remove isopropanol (IPA). Synthesis conditions for the novel photocatalyst, including calcination temperature and copper loading, were varied before photocatalysis to obtain at the optimal reaction efficiency. The effects of initial IPA concentration, oxygen content, and catalyst dosage were also observed. Finally, catalyst reusability was analyzed. X-ray photoelectron spectroscopy fitting revealed Ti, Cu, C, and O peaks in the synthesized catalyst. After a 60-min reaction with 100% oxygen as the carrying gas, nearly 100% of the IPA was converted. Overall, the optimal IPA conversion efficiency and acetone and carbon dioxide selectivity were achieved when the photocatalyst was synthesized at a calcination temperature of 550 °C and copper loading of 1.8%, along with a 100% oxygen carrying gas and a 3-mm discharge gap.

Decomposition of Hydroxylammonium Nitrate Solution Over Nanoporous CuO Supported on Honeycomb.

We investigated the influence of a copper loading strategy over a honeycomb structure on the catalytic performance during the decomposition of a hydroxylammonium nitrate (HAN) aqueous solution. Copper was supported on the honeycomb surface by means of a metal coating method (MC), i.e., a method of directly coating a metal, and a metal alumina coating method (MAC), i.e., a method of coating a mixture of metal and alumina. The properties of the catalysts were analyzed by N₂ adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The Cu(16.8)/honeycomb-MC catalyst showed a lower decomposition onset temperature during the decomposition of the HAN aqueous solution compared to that over the Cu(7.0)/honeycomb- MAC catalyst, an outcome ascribed to the higher copper loading and the higher dispersion of copper in the Cu(16.8)/honeycomb-MC catalyst compared to that in the other catalyst. The Cu(16.8)/honeycomb-MC catalyst was confirmed to have both excellent activity and heat resistance during the decomposition of a HAN aqueous solution.