Effect Of Copper Precursors Research Articles

Effect of copper precursors on CO oxidation catalyzed by CuO-CeO2 prepared by solvothermal method

In this paper, the CuO–CeO2 catalyst was prepared by a direct solvothermal method. The effects of different copper salt precursors (copper nitrate, copper acetate, copper sulfate) on the catalytic performance of the prepared catalyst for CO oxidation were investigated. The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 physical adsorption, inductively coupled plasma-atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption analysis of CO (CO-TPD), in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), and temperature-programmed reduction with H2 (H2-TPR). The results show that the CuO–CeO2 catalyst prepared with copper acetate as precursor (CC-A) exhibits the best catalytic activity for CO oxidation at low temperatures, with T50 and T90 values of 62 and 78 °C respectively, which is mainly attributed to its large specific surface area, pore volume, CO adsorption capacity, and large amount and strong reactivity of surface oxygen. However, the CuO–CeO2 catalyst prepared with copper nitrate as precursor (CC–N) displays better stability and resistance to water or CO2 poisoning than CC-A.

(PEFC&E 3rd Place Best Poster Winner) Effect of Copper Precursor and Composition on Catalytic Activity of Fe-N-C Catalysts for Oxygen Reduction Reaction in Alkaline Medium

Platinum-based catalysts have been frequently used for proton exchange membrane fuel cells (PEMFCs) over the decades [1]. However, its high cost and scarcity led to attention to non-precious metal catalysts (NPMCs) with anion exchange membrane [2]. One of the most promising NPMCs is iron and nitrogen co-doped carbon (Fe-N-C). Since nitrogen (N), iron (Fe) and carbon (C) are plentiful on the Earth, the cost of Fe-N-C is much lower than that of Pt-based catalysts. In order to improve the activity of Fe-N-C, various transition metals have been introduced. Among them, the introduction of copper (Cu) is expected to be able to achieve higher performance by imitating the cytochrome-c-oxidase structure [3]. In this study, the effect of different types of Cu precursors on the physical and electrochemical properties of Fe-N-C catalysts was investigated. Copper chloride, nitrate, sulfate, and acetate with different contents were applied to the preparation of Fe-N-C catalysts.Cu introduced Fe-N-C catalysts were named as FexCuy-N-C (x and y are a molar ratio of Fe and Cu, respectively.). FeCu-N-C was synthesized by nano-replication of SBA-15 using iron chloride (FeCl3), 1,10-phenanthroline, and Cu precursors, phosphoric acid and citric acid. For P doping, phosphoric acid was impregnated into silica pores. Citric acid was exploited as a carbon precursor and acid catalyst for polymerization simultaneously. After pyrolysis at 900 ˚C under Ar atmosphere for 3 h, silica was etched by 20 wt.% HF, followed by acid leaching with 0.5 M sulfuric acid at 80 ˚C for 8 h. After dried at 80 ˚C overnight, it was heat treated again under Ar+NH3 atmosphere at 900 ˚C for 1 h.From X-ray photoelectron spectroscopy, N 1s spectra of all catalyst showed that the contents of graphitic N were about 50% due to two heat treatment steps. And amount of pyridinic N was about 30% of entire surface nitrogen. From elemental analysis technique, N content was about to be 3 at.%. During acid leaching and heat treatment most of unwanted iron clusters such as iron oxides and iron carbides with low number of carbon shells were eliminated from the surface. Therefore, less than 0.1 at.% of Fe and Cu were confirmed from Fe 2p and Cu 2p spectra. Hence, there were no obvious peaks from Fe or Cu crystal while only carbon peaks existed in X-ray diffraction pattern. Surface area and porosity of catalysts were investigated by N2 adsorption and desorption technique. Surface areas were in the range of 1000-1050 m2/g, and pore volumes were about to be 1.1 cm3/g. Interestingly, with increasing content of citric acid, enlargement of mesopores from 4 to 5 nm was shown and transition of pore shape from slit to cylinder as confirmed by hysteresis of N2 ads/des isotherm curve. It infers that citric acid can effectively help the nano-replication process by its bifunctional role.With the different molar ratios of Fe and Cu, oxygen reduction activity was measured by a rotating disk electrode technique. Catalyst using CuSO4 was used since its catalytic activity was superior to those of catalyst which used copper chloride or acetate. The half-wave potential of catalyst with Cu1.0 was higher than other catalysts (918 mV), which is 16 mV higher than that (902 mV) of Fe-N-C. Cu-N-C had the lowest oxygen reduction activity (824 mV). Therefore, with proper content of Cu and type of precursor, optimized performance could be achieved.

Effect of Copper Precursors on the Activity and Hydrothermal Stability of CuII−SSZ−13 NH3−SCR Catalysts

A series of CuII−SSZ−13 catalysts are prepared by in-situ hydrothermal method using different copper precursors (CuII(NO3)2, CuIISO4, CuIICl2) for selective catalytic reduction of NO by NH3 in a simulated diesel vehicle exhaust. The catalysts were characterized by X−ray diffraction (XRD), scanning electron microscope (SEM), X−ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, hydrogen-temperature-programmed reduction (H2−TPR), ammonia temperature-programmed desorption (NH3−TPD), and 27Al and 29Si solid state Nuclear Magnetic Resonance (NMR). The CuII−SSZ−13 catalyst prepared by CuII(NO3)2 shows excellent catalytic activity and hydrothermal stability. The NO conversion of CuII−SSZ−13 catalyst prepared by CuII(NO3)2 reaches 90% at 180 °C and can remain above 90% at a wide temperature range of 180–700 °C. After aging treatment at 800 °C for 20 h, the CuII−SSZ−13 catalyst prepared by CuII(NO3)2 still exhibits above 90% NO conversion under a temperature range of 240–600 °C. The distribution of Cu species and the Si/Al ratios in the framework of the synthesized CuII−SSZ−13 catalysts, which determine the catalytic activity and the hydrothermal stability of the catalysts, are dependent on the adsorption capacity of anions to the cation during the crystallization process due to the so called Hofmeister anion effects, the NO3− ion has the strongest adsorption capacity among the three kinds of anions (NO3−, Cl−, and SO42−), followed by Cl– and SO42– ions. Therefore, the CuII−SSZ−13 catalyst prepared by CuII(NO3)2 possess the best catalytic ability and hydrothermal stability.

Phase controllable synthesis of CuS nanoparticles by chemical co-precipitation method: Effect of copper precursors on the properties of CuS

The studies focusing on the synthesis of CuS nanoparticles (NPs) by Chemical Co-Precipitation method (CCP) along with detailed growth mechanism are limited. In addition, the synthesis of CuS NPs in water solvent is highly encouraged as water is served as the best eco-friendly solvent. In the present report, taking the advantage of Cu+1 oxidation in the aqueous medium, CuS NPs were synthesized using CuCl and thiourea (Tu) via CCP in presence of naturally abundant water solvent under open atmosphere. In addition, the effect of different copper precursors (such as CuCl, CuCl2, and CuSO4 in combination with thiourea) and the mole ratio of Cu/S on the properties of CuS NPs were also investigated. XRD analysis showed the single-phase CuS for the combination of CuCl + Tu at Cu/S = 1:2 and CuCl2 (or CuSO4) + Tu at Cu/S = 1:1. For other growth conditions, copper-rich composition with mixed phases was observed. XPS analysis showed both +1 and + 2 oxidation states for copper in CuS NPs synthesized from CuCl and Tu at Cu/S = 1:2. The CuS NPs showed broad absorptions in the UV–Vis and NIR regions due to excitonic absorption and localized surface plasmon resonance (LSPR). The optical band gap energy of CuS NPs was varied in the range of 2.05–2.34 eV, depending on the type of copper precursor and Cu/S mole ratio used. The synthesized CuS NPs have potential applications in the visible solar light-driven dye degradation.

Effect of copper precursors on the catalytic performance of Cu-ZSM-5 catalysts in N 2 O decomposition

Abstract Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 (Si/Al ratio = 15) with aqueous solutions of different Cu precursors (CuCl2, Cu(NO3)2, CuSO4, Cu(CH3COO)2, and ammoniacal copper (II) complex ion). After being pretreated in flowing He at 500 °C to form active Cu+, these catalysts exhibited quite different activities in catalytic decomposition of N2O. CZM-AC(II) (prepared by ammoniacal copper (II) complex ion) with 9.4 wt% Cu content was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N2O conversion at 400 °C. CZM-CA (prepared using Cu(CH3COO)2 as the Cu precursor) with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N2O conversion at 425 °C. CZM-CC, CZM-CN, and CZM-CS prepared by using CuCl2, Cu(NO3)2, or CuSO4 as the Cu precursor with similar Cu contents (≈ 1.7 wt%) were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N2O conversion at 500 °C. XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples. The superior activity of CZM-AC(II) can be attributed to the high contents of total Cu+ and dimeric Cu+ among these samples. The influence of co-fed O2 or H2O on the catalytic performance of typical samples was also studied.

Synthesis and physicochemical characterization of CuxS-NiySz/FNBR and CuS-NiySz/FNBR nanocomposites from β-NiS/FNBR by ion exchange method: (x=1; 1.8); (y=1; 3); (z=1; 4)

β-NiS nanoparticles (NPs) grown through SILAR technique into functionalized nitrile butadiene rubber (FNBR) were used for the synthesis of CuS-NiS/FNBR and Cu1.8S-Ni3S4/FNBR nanocomposites (NCs). The evaluated band gap decreased from 2.8 eV to 2.3 eV and 2.21 eV using 0.25 M of CuSO4 × 5H2O and 0.5 M of CuCl2 × 2H2O, respectively. The effect of copper precursors and concentration of Cu2+ ions on the particle size, chemical composition of NCs and properties has been discussed in detail. Different structural phases of nickel sulfide and copper sulfide were obtained using NiS/FNBR nanocomposites as a precursor for ion exchange reaction by Cu2+ ions. Properties of CuxS-NiySz/FNBR and CuS-NiySz/FNBR nanocomposites obtained after modification have been studied and compared with initial nanocomposite of NiS/FNBR. The average particle size increased from 8.5 nm to 13.5 nm and 15 nm after ion exchange modification. By EPR spectrum the superhyperfine splitting is seen in the spectrum of CuS-NiySz/FNBR, ACu = 107.3 G. In perpendicular section the bandwidth of the spectrum (ΔH) is equal to 930 G. Recording to SEM images very clearly imaged spherical nanoparticles have been observed.

Effect of copper precursors on the catalytic activity of Cu/ZSM-5 catalysts for selective catalytic reduction of NO by NH3

The Cu/ZSM-5 catalysts prepared by different copper precursors were used for the selective catalytic reduction (SCR) of NO x with NH3. The Cu/ZSM-5 catalyst prepared by the copper nitrate (Cu/ZSM-5-N) presented the best performance among the Cu/ZSM-5 catalysts and showed above 90 % NO x conversion at 225–405 °C. The average particle size of CuO was 5.82, 9.20, and 11.01 nm over Cu/ZSM-5-N, Cu/ZSM-5-S (prepared by copper sulfate), and Cu/ZSM-5-C (prepared by copper chloride), respectively. The Cu/ZSM-5-N catalyst showed the highly dispersed copper species, the strong surface acidity, and the excellent redox ability compared with the Cu/ZSM-5-C and Cu/ZSM-5-S catalysts. The Cu+ and Cu2+ existed in the Cu/ZSM-5 catalysts and the abundant Cu+ over Cu/ZSM-5-N might be responsible for the superior SCR activity.

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.

Synthesis, characterization and photovoltaic studies of CuInS2 nanostructures

In this investigation, (1,8-diamino-3,6-dioxaoctan)copper(II)sulfate, ([Cu(DADO)]SO4), bis(propylenediamine)copper(II)sulfate, and ([Cu(pn)2]SO4) were applied as copper precursors to fabricate CuInS2 (CIS) nanostructures in presence of microwave irradiation. Besides the effect of copper precursor, the effect of microwave power and time of irradiation on morphology of CuInS2 nanostructures were investigated. The as-prepared products were analyzed by XRD, PL, FT-IR, EDS, and SEM. The results of XRD patterns were indicated that pure CuInS2 with tetragonal phase could be only obtained after annealing at 400 °C for 2 h in a mixture of 85 % Ar and 15 % H2 gases. SEM images were shown that regular hierarchical nanostructures of CuInS2 were obtained with the aid of [Cu(pn)2]SO4 as copper precursor under 900 W irradiation power for 12 min. The photovoltaic behaviors of as-synthesized CuInS2 nanostructures were studied after deposition of CdS film on chemical bath. CuInS2 film was directly deposited on the surface of the CdS film through doctor blade method. The as-deposited CdS/CuInS2 films were applied in photovoltaic measurements.

Non-vacuum processed Cu2ZnSnS4 thin films: Influence of copper precursor on structural, optical and morphological properties

In this study, thin film of Cu2ZnSnS4 (CZTS) has been successfully deposited by sol–gel dip-coating method on glass substrates. In the sol–gel process, glacial acetic acid, ethanol and triethanolamine were used as solvent and stabilizer. Three different copper precursors of copper (III) nitrate hemipentahydrate, copper (II) 2-ethylhexanoate and copper (II) acetate in the solution were used to obtain CZTS thin films. Effect of copper precursor on the structural, morphological and optical properties was investigated. X-ray diffraction (XRD) and Raman spectroscopy studies showed that CZTS thin films exhibited kesterite structure with a (112) plane preferred orientation and Raman shift of 336cm−1, respectively.

Synthesis and characterization of CuInSe2 nanocrystals via facile microwave approach and study of their behavior in solar cell

Copper indium selenide, CuInSe2, crystals with different morphologies and particle sizes were obtained via a simple microwave reaction among different copper precursors, indium chloride (InCl3) and selenium tetrachloride (SeCl4). The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL) spectroscopy. The effect of copper precursor, microwave time, and power on the particle size and morphology has been investigated. The band gap of CuInSe2 nanoparticles was calculated by UV–vis and PL spectrum. The thin film of CIS nanoparticles and solar cell were fabricated and characterized by I–V curve.

Effect of Copper Precursor on the Stabilization of Titania Phases, and the Optical Properties of Cu/TiO2 Prepared with the Sol−Gel Technique

In the sol−gel Cu/TiO2 system, nanocrystalline brookite, which was stable even after annealing the sample at 400 °C, was generated in high concentrations. This was achieved with copper chloride as copper precursor. The respective samples had a light absorption band at 562 nm that corresponded to an energy bandgap of 2.30 eV, which is smaller than the values reported for titania. When copper sulfate was the precursor, brookite was absent, but nanocrystalline anatase, the main phase, was stabilized even at 800 °C by sulfate ions. After annealing the samples at low temperatures, copper was well dispersed for 1 wt % copper, but part of it segregated forming copper compounds when the copper concentration was 10 wt %. By annealing the samples at 800 °C, copper oxidized to CuO; except in the 10 wt %-copper sample prepared with copper sulfate, where it formed antlerite.