Catalyst Of Cu Research Articles

Ultrasmall Cu Nanoparticles Supported on Crystalline, Mesoporous ZnO for Selective CO2 Hydrogenation

AbstractConverting CO2 to value‐added chemicals, e. g., CH3OH, is highly desirable in terms of the carbon cycling while reducing CO2 emission from fossil fuel combustion. Cu‐based nanocatalysts are among the most efficient for selective CO2‐to‐CH3OH transformation; this conversion, however, suffers from low reactivity especially in the thermodynamically favored low temperature range. We herein report ultrasmall copper (Cu) nanocatalysts supported on crystalline, mesoporous zinc oxide nanoplate (Cu@mZnO) with notable activity and selectivity of CO2‐to‐CH3OH in the low temperature range of 200–250 °C. Cu@mZnO nanoplates are prepared based on the crystal‐crystal transition of mixed Cu and Zn basic carbonates to mesoporous metal oxides and subsequent hydrogen reduction. Under the nanoconfinement of mesopores in crystalline ZnO frameworks, ultrasmall Cu nanoparticles with an average diameter of 2.5 nm are produced. Cu@mZnO catalysts have a peak CH3OH formation rate of 1.13 mol h−1 per 1 kg under ambient pressure at 246 °C, about 25 °C lower as compared to that of the benchmark catalyst of Cu−Zn−Al oxides. Our new synthetic strategy sheds some valuable insights into the design of porous catalysts for the important conversion of CO2‐to‐CH3OH.

Solar‐Driven Water Splitting in Photovoltaic Electrolysis Systems Using Copper Terpyridine Complexes as Oxygen Evolution Catalysts

Copper complexes, as kinds of molecular catalysts bioinspired from the copper O2‐activating enzymes, are attractive targets for water oxidation, which can undergo facile and reversible OO bond formation and cleavage under mild conditions. Herein, three copper(II) complexes of Cu(tpy), Cu(ctpy), and Cu(pctpy) are investigated as oxygen evolution catalysts, which are designed and synthesized using α,α′,α″‐terpyridyl(tpy) derivatives as ligands. In the electrochemical measurements, the carboxylic‐functionalized catalysts of Cu(ctpy) and Cu(pctpy) exhibit high water oxidation turnover frequencies of 1027 and 3363 s−1, respectively. The astonishing rates of O2 production exceed the oxygen evolution complex in natural photosystem II. Moreover, the photovoltaic electrolysis (PVE) system is constructed by connecting Si solar panels with the copper complex‐decorated electrodes. Under the irradiation of AM1.5G‐simulated sunlight, a high photocurrent density of 5.47 mA cm−2 and solar‐to‐hydrogen efficiency of 6.81% are achieved for solar water splitting without external bias. This is the first report PVE system using copper complex as a oxygen evolution catalyst molecular catalyst, which is of great significance to simulate the catalytic water oxidation process of natural enzymes and build an artificial photosynthesis system to achieve green, efficient, and stable decomposition of aquatic oxygen.

Development and Testing of Ni-Cu Bimetallic Catalysts for Effective Syngas Production via Low-Temperature Methane Steam Reforming

In the present work, novel bi-metallic catalysts for syngas production at low temperature steam reforming are developed, characterised and tested. Steam methane reforming by using bi-metallic Ni-Cu catalysts found to balance the product of CO to CO2 ratios, while affected the water gas shift reaction by increasing the hydrogen selectivity up to 600°C. The addition of different amounts of Cu (3, 5, 7, 10 wt%) to the Ni catalyst for methane steam reforming showed different reactivity trends. One of the major outcomes of this work is the maximum load capacity of Cu (5wt.%Cu) to maintain the reactivity. For comparison purposes, mono-metallic catalysts of Cu and Ni were developed and tested along with the bi-metallic ones. The activity of the reaction decreased by doping more than 5wt.%Cu which affected the amount of hydrogen produced. This is related to the possible limited number of available sites required for hydrogen adsorption to maintain the reaction of methane steam reforming. Another important outcome of this work is the bi-metallic Ni-Cu catalysts did not decrease the amount of carbon formation.

Enhanced Photoelectrochemical Water Splitting of Black Silicon Photoanode with pH‐Dependent Copper‐Bipyridine Catalysts

Since the water oxidation half-reaction requires the transfer of multi-electrons and the formation of O-O bond, it's crucial to investigate the catalytic behaviours of semiconductor photoanodes. In this work, a bio-inspired copper-bipyridine catalyst of Cu(dcbpy) is decorated on the nanoporous Si photoanode (black Si, b-Si). Under AM1.5G illumination, the b-Si/Cu(dcbpy) photoanode exhibits a high photocurrent density of 6.31 mA cm-2 at 1.5 VRHE at pH 11.0, which is dramatically improved from the b-Si photoanode (1.03 mA cm-2 ) and f-Si photoanode (0.0087 mA cm-2 ). Mechanism studies demonstrate that b-Si/Cu(dcbpy) has improved light-harvesting, interfacial charge-transfer, and surface area for water splitting. More interestingly, b-Si/Cu(dcbpy) exhibits a pH-dependent water oxidation behaviour with a minimum Tafel slope of 241 mV/dec and the lowest overpotential of 0.19 V at pH 11.0, which is due to the monomer/dimer equilibrium of copper catalyst. At pH ∼11, the formation of dimeric hydroxyl-complex could form O-O bond through a redox isomerization (RI) mechanism, which decreases the required potential for water oxidation. This in-depth understanding of pH-dependent water oxidation catalyst brings insights into the design of dimer water oxidation catalysts and efficient photoanodes for solar energy conversion.

Design of Binary Cu-Fe Sites Coordinated with Nitrogen Dispersed in the Porous Carbon for Synergistic CO2 Electroreduction.

To relieve the green gas emission and involve the carbon neutral cycle, electrochemical reduction of CO2 attracts more and more attention. Herein, a biatomic site catalyst of Cu-Fe coordinated with the nitrogen, which is doped in the carbon matrix (denoted as Cu-Fe-N6 -C), is designed. The as-obtained Cu-Fe-N6 -C exhibits higher performance than that of Cu-N-C and Fe-N-C, owing to bimetallic sites, proving synergistic functions based on different molecules and their interfaces. Cu-Fe-N6 -C shows high selectivity toward CO, with high Faradaic efficiency (98% at -0.7V), and maintaining 98% of its initial selectivity after 10 h electrolysis. The experimental results and theoretical calculations reveal that the synergistic catalysis of different metallic sites enlarges the adsorption enthalpy of CO2 , reducing the activation energy result in generating high selectivity, activity, stability, and low impedance.

Hydrogenation of CO2 to Methanol and Dimethyl Ether over a Bifunctional Cu·ZnO Catalyst Impregnated on Modified γ-Alumina

Bifunctional catalysts of Cu·ZnO supported on modified γ-Al2O3 were prepared and tested in the direct hydrogenation of CO2 to methanol and dimethyl ether (DME). The γ-Al2O3 modification was carried...

Catalytic degradation of real-textile azo-dyes in aqueous solutions by using Cu–Co/halloysite

Catalytic degradation of textile dyes in diluted aqueous solutions with minimal consumption of energy is a great challenge for wastewater treatment and environmental protection. Efficient heterogeneous catalysts are needed to completely oxidize azo-dyes under soft conditions. In this work, catalysts of Cu–Co oxide (1:2 molar ratio) supported on halloysite (Ha) nanotubes (CuCo(5%)/Ha and CuCo(10%)/Ha) were synthesized and used in the catalytic wet peroxide oxidation of reactive yellow 145 (RY-145) and basic red 46 (BR-46). The catalysts were characterized by chemical analysis, X-ray diffraction, Raman spectroscopy, \(\hbox {N}_{2}\) adsorption isotherms, scanning electron microscopy and transmission electron microscopy. The results showed that the synthesized catalysts possess nanotubular structure with good mesoporosity, and the spinel structure \(\hbox {CuCo}_{2}\hbox {O}_{4}\) was identified as the active phase deposited on Ha. The catalysts degraded these azo-dyes in diluted solutions (\(22\, \hbox {mg l}^{-1}\) of RY-145 and \(35\, \hbox {mg l}^{-1}\) of BR-46) under mild reaction conditions (\(25^{\circ }\hbox {C}\), atmospheric pressure, pH 4 and minimum amounts of both catalyst and \(\hbox {H}_{2}\hbox {O}_{2})\). Significant levels of dye conversion (\(93.1\pm 2.2\%\) for RY-145 and \(54.4 \pm 2.0\%\) for BR-46) were achieved in a relatively short time. In addition, significant values of total organic carbon removal (\(59.5 \pm 1.8\%\) for RY-145 and \(33.9 \pm 1.4\%\) for BR-46) were obtained, indicating the total oxidation of a significant fraction of these dyes to \(\hbox {CO}_{2}\) and \(\hbox {H}_{2}\hbox {O}\).

Supported transition metal catalysts of Cu(II), Mn(II) and Co(II): synthesis, characterization, and catalytic behavior

A variety of heterogeneous transition metal Schiff base complexes have been prepared by their intercalation in layered double hydroxide, abbreviated as LDH-[SALABA-M] {where M is Cu, Mn and Co}. The synthesized catalysts are characterized by various analytical techniques like X-ray diffraction, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, inductive coupled plasma-atomic emission spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller surface area etc. The aforesaid catalysts are employed for the oxidation of cyclohexene. Effect of various metals, substrate to oxidant molar ratio, temperature, and catalyst amount etc. have been studied so as to derive optimum conditions for obtaining maximum conversion. Tert-butyl hydroperoxide has been used as an oxidant in acetonitrile solvent. The oxidation products obtained are 2-cyclohexene-1-ol and 2-cyclohexene-1-one. The catalyst, LDH-[SALABA-Cu(II)] is recycled ten times in consecutive runs. Additionally, mechanism of reaction is found out using quenching study.

Atomic Cu on nanodiamond-based sp2/sp3 hybrid nanostructures for selective hydrogenation of phenylacetylene

Abstract In this work, a nanodiamond-based sp2/sp3 hybrid nanostructure composed of a nanodiamond (ND) core and sp2 surfaces was fabricated for supporting Cu single atoms as a catalyst for selective hydrogenation of phenylacetylene. Cu supported on ND after annealing at 900 °C (Cu/ND-900) showed improved activity in comparison to the catalyst of Cu supported on pristine ND (Cu/PND). Surface analyses reveal that Cu single atoms display a high dispersion and an appearance of Cu(0)/Cu(I) surface state when supported on ND-900. Our work indicates a possibility of utilizing hybrid carbon structures with tunable sp2/sp3 ratios for approaching improved-performance catalyst system.

Sonochemical Syntheses of a Hetero Metal–Organic Complex, a Precursor for Producing Clean Energy Source of Hydrogen

In the present study, a hetero nuclear complex formulated as [Cu(H2O)5Ni(dipic)2]·2H2O (1) that dipic is pyridine-2,6-dicarboxylic acid, was synthesized by a sonochemical process and characterized by several techniques such as elemental analysis, atomic absorption spectroscopy, conductivity measurement, Fourier transform infrared spectroscopy, ultra violet–visible spectroscopy, thermal decomposition and single crystal X-ray diffraction. Complex 1 was dispersed on the rutile (R-TiO2) as support and after thermal decomposition, catalyst of Cu–Ni/(R-TiO2) (2) was prepared. Nano-catalyst of 2 was studied by scanning electron microscopy, Brunauer–Emmett–Teller, transmission electron microscopy and powder X-ray diffraction. Catalyst 2 was applied as a catalyst in the water–gas shift reaction in the temperature range of 150–350 °C. In addition, catalyst of 2 was synthesized by co-precipitation and impregnation methods as references catalyst. The results showed that the catalyst of 2, synthesized by thermal decomposition of complex 1, has the highest catalytic performance compared to reference catalysts. Moreover, the results confirmed that the temperature of 250 °C is the optimal temperature for all catalysts. In another section of this study, the performance of anatase and rutile supported Cu–Ni/(R-TiO2) and Cu–Ni/(A-TiO2) catalysts prepared through calcination of 1 were compared for the amount of hydrogen produced. Stability test performed on catalyst of 2 at optimum temperature (250 °C) showed that all catalysts are stable for 12 h.

43.太平洋炭の液化反応における水酸化銅の触媒効果(1) : 液化率に与える水酸化銅とその関連化合物の触媒効果

43.太平洋炭の液化反応における水酸化銅の触媒効果(1) : 液化率に与える水酸化銅とその関連化合物の触媒効果

A rapid screening platform for catalyst discovery in azide–alkyne cycloaddition by ICP-MS/MS

We developed a rapid high-throughput screening platform using a modified ICP-MS/MS system for monovalence metal ions catalysts discovery in azide–alkyne cycloaddition. Among the ten monovalence metal ions in the first row of periodic table containing Sc+, Ti+, V+, Cr+, Mn+, Fe+, Co+, Ni+, Cu+, and Zn+, five monovalence metal ions of Sc+, Co+, Ni+, Cu+ and Zn+ ions show relatively stronger catalytic activities than others. The catalytic mechanism of Sc+, Co+ and Ni+ ions is similar to the Cu+ ions, but Zn+ ions take a different catalytic route. A yields range of 77–98% for azide-alkyne cycloaddition was achieved with Sc+, Co+, Ni+, Cu+ and Zn+ ions as catalyst, respectively by using a UV laser ablation reactor in 20min, notable that the yields of Co+ and Sc+ ions were even higher than the common catalyst of Cu+ ions. The proposed platform would be used not only for catalyst discovery in azide-alkyne cycloaddition, but also for the discovery of single atom/ion catalysts in other organic reactions.

Palladium networks decorated by cuprous oxide for remarkably enhanced electrocatalytic activity of methanol oxidation reaction with high CO-tolerance

Abstract The CuO nanorods (NRs) are prepared with the help of inositol hexakisphosphate which serves as a binding agent and stabilizer. We have successfully fabricated Cu 2 O-decorated palladium networks (Cu 2 O/Pd Networks) by using such CuO NRs as reaction beds. Transmission electron microscopy images show that Cu 2 O/Pd network is composed of small and irregular fused nanoparticles with an average size of about 10 nm. Electrochemical results depict that the as-synthesized catalyst exhibits 2-fold higher activity for methanol oxidation than the commercially available 20% Pd/C catalyst and Pd black catalyst. Furthermore, CO-tolerance is also remarkably enhanced due to the presence of Cu 2 O. Such highly active, low-cost, and superiorly CO-tolerant catalysts of Cu 2 O/Pd Networks will open up a new avenue for direct methanol fuel cells.

Promotion effect of Co on Cu–Zn–Al/Hβ catalyst for light hydrocarbons (C3–C5) synthesis from syngas

The synthesis of light hydrocarbons from syngas has received great attention due to the environmentally benign characteristics and uses as clean fuels and raw chemical feedstock of C3–C5 hydrocarbons. In this work, the synthesis of C3–C5 hydrocarbons was carried out over hybrid catalysts of Cu–Zn–Al/Co–Hβ at low reaction temperature (290°C). Introduction of minor amount of Co significantly promoted the yield of C3–C5 hydrocarbons. When the weight percentage of Co in Co–Hβ was 0.113wt.%, Cu–Zn–Al/Co–Hβ showed the best performance. This study will contribute to the development of efficient catalysts for production of hydrocarbons from syngas.

ChemInform Abstract: Rice Husk Derived Nanosilica Supported Cu(II) Complex: An Efficient Heterogeneous Catalyst for Oxidation of Alcohols Using TBHP.

AbstractVarious primary and secondary alcohols are oxidized using a novel heterogenized catalyst of Cu(II) complex immobilized onto nanosilica obtained from rice husk.

Rice husk derived nanosilica supported Cu(ii) complex: an efficient heterogeneous catalyst for oxidation of alcohols using TBHP

We have developed a heterogenized catalyst of Cu(ii) complex immobilized onto nanosilica obtained from rice husk (RH), through Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized nanosilica and acetamide.

Synthesis of C2+ hydrocarbons by CO2 hydrogenation over the composite catalyst of Cu–Zn–Al oxide and HB zeolite using two-stage reactor system under low pressure

The combination of methanol synthesis and methanol-to-gasoline (MTG) reaction is a beneficial process to produce particular C2+ hydrocarbons from CO2 and H2, because MTG reaction can produce C2+ hydrocarbons selectively without the formation of methane. However, the composite catalysts consisting of methanol synthesis catalyst and zeolite previously reported have produced C2+ hydrocarbons in poor yields especially under low pressure conditions. This paper reports the high yield production of C2+ hydrocarbons by CO2 hydrogenation using a two-stage reaction system consisting of a Cu–Zn–Al oxide catalyst in the first reactor and a composite catalyst of the Cu–Zn–Al oxide and HB (zeolite beta) in the second reactor. The key points of this system are reversed water-gas-shift (RWGS) reaction in the first reactor and the following H2O removal before the second reactor. The gas mixture supplied to the second reactor containing much amount of CO and little H2O enhanced the methanol synthesis and suppressed the methanol decomposition to CO over the Cu–Zn–Al oxide catalyst in the composite catalyst, promoting the MTG reaction to produce C2+ hydrocarbons over HB zeolite. The highest yield of C2+ hydrocarbons reached to approximately 15C-mol% under 0.98MPa.

Charaterization and Catalytic Activity of CuO and NiO Supported on ZrO<sub>2</sub> for CO Low Temperature Oxidation

ZrO2 support has been prepared by sol-gel and coprecipitation method. CuO and NiO were supported on the supports and they were the activity metals for the catalysts. The CO conversion was tested. The light-off temperature of CO oxidation was 22°C and CO conversion efficiency was up to 50% at 169°C. The prepared catalysts of Cu, Ni supported on ZrO2-A had a high activity for CO oxidation at low temperature.

Resonance scattering spectrum detection of trace using nanogold probe as catalyst of Cu(II)-glucose reaction

exhibited catalytic effect on the cracking reaction of double-stranded DNA (dsDNA) to form a short single-stranded DNA (ssDNA) that protected the nanogold (NG) to produce stable NGssDNA conjugate. The un-protected NG was aggregated to form NG aggregates (NGA) that appeared a resonance scattering (RS) peak at 542 nm. Unlike NGA, the NGssDNA exhibited a strong catalytic activity on the Cu2O particle reaction of Fehling reagent-glucose that can be monitored by RS technique at 608 nm. When the concentration increased, the NGssDNA increased, and the RS intensity at 608 nm increased. The increased RS intensity ΔI 608 nm was linear to the concentration in the range of 15–200 pmol L−1, with a regression equation of ΔI 608 nm = 1.24 C + 4.6, and a detection limit of 5 pmol L−1. This new RS assay was applied to assay in water sample, with satisfactory results.

Complexs of Poly(1-vinylimidazole-co-methyl methacrylate) and Copper Ion as Catalysts for the Oxidation of Ethylbenzene

This paper was reported a polymeric support metal catalyst and its application in oxidation of ethylbenzene with molecular oxygen. The Poly(1-vinylimidazole-co-methyl methacrylate) copolymer (PVM) was directly mixed with copper sulfate solution to prepare the catalyst of Cu(II)-PVM. The appropriate reaction temperature and amount of catalyst were 130°C and 0.2g. Recycling studies indicated that the catalyst could be recycled at least four times without significant decrease of catalytic activity.