Metal-organic-framework-derived copper-based catalyst for multicomponent C-S coupling reaction

Copper-based metal-organic frameworks(Cu-MOFs)are a promising multiphase catalyst for catalyzing C-S coupling reactions by virtue of their diverse structures and functions.However,the unpleasant odor and instability of the organosulfur,as well as the mass-transfer resistance that exists in multiphase catalysis,have often limited the catalytic application of Cu-MOFs in C-S coupling reactions.In this paper,a Cu-MOFs catalyst modified by cetyltrimethylammonium bromide(CTAB)was designed to enhance mass transfer by increasing the adsorption of organic substrates using the long alkanes of CTAB.Concurrently,elemental sulfur was used to replace organosulfur to achieve a highly efficient and atom-economical multicomponent C-S coupling reaction.

Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

A highly hydrothermal stable copper-based catalyst for catalytic wet air oxidation of m-cresol in coal chemical wastewater

Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.

Catalytic combustion of methane over nano ZrO_2-supported copper-based catalysts

The nano ZrO2-supported copper-based catalysts for methane combustion were investigated by means of N2 adsorption, TEM, XRD, H2-TPR techniques and the test of methane oxidation. Two kinds of ZrO2 were used as support, one （ZrO2-1） was obtained from the commercial ZrO2 and the other （ZrO2-2） was issued from the thermal decomposition of zirconium nitrate. It was found that the CuO/ZrO2-2 catalyst was more active than CuO/ZrO2-1. N2 adsorption, H2-TPR and XRD measurements showed that larger surface area, better reduction property, presence of tetragonal ZrO2 and higher dispersion of active component for CuO/ZrO2-2 than that of CuO/ZrO2-1. These factors could be the dominating reasons for its higher activity for methane combustion.

Effect of preparation methods of aluminum emulsions on catalytic performance of copper-based catalysts for methanol synthesis from syngas

Various Cu/ZnO/Al2O3 catalysts have been synthesized by different aluminum emulsions as aluminum sources and their pertormances tor methanol synthesis from syngas have been investigated. The influences of preparation methods of aluminum emulsions on physicochemical and catalytic properties of catalysts were studied by XRD, SEM, XPS,N2 adsorption-desorption techniques and methanol synthesis from syngas. The preparation methods of aluminum emulsions were found to influence the catalytic activity, CuO crystallite size, surface area and Cu0 surface area and reduction process. The results show that the catalyst CN using the aluminum source prepared by addition the ammonia into the aluminum nitrate （NP） exhibited the best catalytic performance for methanol synthesis from syngas.

Comprehensive first-principles studies on phase stability of copper-based halide perovskite derivatives A_lCu_mX_n(A = Rb and Cs;X = Cl, Br, and I)

Recently,inorganic copper-based halide perovskites and their derivatives(CHPs)with chemical formulas AlCumXn(A=Rb and Cs;X=Cl,Br and I;l,m,and n are integers.),have received increasing attention in the photoluminescence field,due to their lead-free,cost-effective,earth-abundant and low electronic dimensionality.Ascribed to flexible valence charge of Cu(Cu1+and Cu2+)and complex competing phases,the crystal structures and phase stabilities of CHPs are complicated and ambiguous,which limits their experimental applications.Via comprehensive first-principles calculations,we have investigated thermodynamic stabilities of possible crystal phases for AlCumXn by considering all the possible secondary phases existing in inorganic crystal structure database(ICSD).Our results are in agreement with existing experiments and further predicted the existence of 10 stable CHPs,i.e.Rb3 Cu2 Br5,Rb3 Cu2 I5,Rb Cu2 Cl3,Rb2 Cu I3,Rb2 Cu Br4,Rb Cu Br3,Rb3 Cu2 Br7,Cs3 Cu2 Br7,Cs3 Cu2 Cl7 and Cs4 Cu5 Cl9,which have not yet been reported in experiments.This work provides a phase and compositional map that may guide experiments to synthesize more novel inorganic CHPs with diverse properties for potential functional applications.

Migration of sulfur in in-situ gasification chemical looping combustion of Beisu coal with iron-and copper-based oxygen carriers

Chemical looping combustion(CLC)is an energy conversion technology with high efficiency and inherent separation of CO_(2).The existence of sulfur in coal may affect the CO_(2) purity and the performance of oxygen carrier due to the interactions between sulfur contaminants and oxygen carrier.The migration of sulfur in Beisu coal during the in-situ gasification chemical looping combustion(i G-CLC)process using two oxygen carriers(iron ore and Cu O/Si O_(2))was investigated respectively.The thermodynamic analysis results showed the formation of metal sulfides was thermodynamically favored at low temperatures and low oxygen excess coefficients,while they were obviously inhibited and the production of SO_(2) was significantly promoted with an increase in temperature and oxygen excess coefficient.Moreover,part of sulfur was captured and fixed in the forms of alkali/alkaline earth metal sulfate due to the high amount of alkali/alkaline earth metal oxides in the coal ash or/and oxygen carrier.The experimental results showed that the sulfur in coal mainly released in the form of SO_(2),and the sulfur conversion efficiency(XS)in the reduction stage were 51.04%and 48.24%when using iron ore and Cu O/Si O_(2) respectively.The existence of metal sulfides was observed in the reduced oxygen carriers.The values of XSin the reoxidation process reached 3.80%and 7.64%when using iron ore and Cu O/Si O_(2) respectively.The residue and accumulation of sulfur were also found on the surfaces of two oxygen carriers.

Effects of Copper-based Nutritional Foliar Fertilizers on Photosynthetic Characteristics,Yield and Disease Control Efficiency of Cotton

[Objectives] The effects of copper-based nutrient foliar fertilizer on photosynthetic characteristics,yield,accumulation and distribution of trace elements in various organs,disease prevention effect and soil enzyme activity were studied,so as to provide a theoretical basis for the application of foliar fertilizers in cotton production. [Methods]Through two years of field experiments,six treatments were set in total,namely spraying water( CK),traditional Bordeaux mixture( BDM),Kocide 2000( KCD),copper-based nutrient foliar fertilizer( CF),iron-copper-based nutrient foliar fertilizer( CFFe),and zinc-boron-copper-based nutrient foliar fertilizer( CFZnB). Randomized block arrangement was adopted. Chlorophyll content in leaves was measured at each growth stage of the cotton. Photosynthetic characteristics of leaves were measured at the peak bolling stage. Plants were sampled at initial boll opening stage. The whole plant was divided into root,stem,leaf and cotton boll parts,in which the total copper,total zinc,total iron contents and accumulations were determined. Soil samples were collected from each plot,followed by the determination of soil enzyme activity. Disease index was investigated at bud,flowering and boll-forming and boll opening stage. [Results]( 1) Spraying CFFe,CFZnB,CF and KCD could significantly improve chlorophyll content of cotton leaves,and the CFFe treatment had the highest increase up to13. 30%,followed by the CFZnB treatment,which was 11. 40% higher than the CK; and photosynthetic rate,stomata conductance and transpiration rate could be improved significantly,and the CFFe treatment showed the highest photosynthetic rate,which increased by 26. 35% compared with the CK,followed by the CFZnB treatment,which increased by 17. 96% compared with CK; and intercellular CO2 concentration was significantly reduced.( 2) Spraying BDM,KCD,CF,CFFe and CFZnB can significantly increase total copper content and accumulation in various cotton organs( except the total copper content in the stem part of the CFZnB treatment; the CFZnB and CFFe treatments can significantly increase total zinc content and accumulation in various cotton organs; and spraying CFFe,CFZnB and CF can significantly increase total iron content and accumulation in various cotton organs( except the total iron content in the stem part of the CF treatment).( 3)Spraying CFFe,CFZnB,CF,KCD and BDM greatly reduced the disease index at flowering and boll-forming and boll opening stages.( 4) The CFZnB and CFFe treatments had the highest soil urease activity,which was 7. 14% higher than that of the CK,but the difference from the CK was not significant; the catalase activity of each treatment was significantly higher than that of the BDM treatment; and the sucrase activity of each treatment was significantly higher than that of the CK.( 5) Spraying CFFe,CFZnB,CF and KCD significantly improved lint yield of cotton,and the CFZnB treatment showed the highest yield increase up to 12. 34%,followed by the CFFe treatment,with an increase in the range of 8. 77%-10. 20%. [Conclusions]Copper-based nutrient foliar fertilizers have dual functions of disease control and prevention and plant nutrition and health care,and not only can significantly increase cotton yield,but also has certain disease prevention effect.It is recommended to use copper-based nutrient foliar fertilizers.

Dynamic Kinetics of Methanol Synthesis over a Commercial Copper-Based Catalyst

Adsorption, surface reaction and process dynamics on the surface of a commercial copper-based catalyst for methanol synthesis from CO/CO2/H2 were systematically studied by means of temperature programmed desorption (TPD), temperature programmed surface reaction (TPSR), in-situ Fourier transform-inferred spec-troscopy(FTIR) and stimulus-response techniques. As a part of results, an elementary step sequence was suggested and a group of ordinary differential equations (ODEs) for describing transient conversations relevant to all species on the catalyst surface and in the gas phase in a micro-fixed-bed reactor was derived. The values of the parameters referred to dynamic kinetics were estimated by fitting the solution of the ODEs with the transient response data obtained by the stimulus-response technique with a FTIR analyzer as an on-line detector.

Tarnish Testing of Copper-Based Alloys Coated with SiO_2-Like Films by PECVD

The tarnishing test in the presence of hydrogen sulfide（H2S） vapors has been used to investigate the tarnish resistance capability of copper-based alloys coated with Si02-like films by means of plasma-enhanced chemical vapor deposition（PECVD） fed with a tetraethoxysilane/oxygen mixture.The chemical and morphological properties of the films have been characterized by using infrared absorption spectroscopy（IR） and scanning electron microscopy（SEM）with energy disperse spectroscopy（EDS）.The corrosion products of the samples after the tarnishing test have been identified by X-ray diffraction analysis（XRD）.It has been found that SiO2-like films formed via PECVD with a high O2 flow rate could protect copper-based alloys from H2S vapor tarnishing.The alloys coated at the O2 flow rate of 20 sccm remain uncorroded after 54days of H2S vapor tarnish testing.The corrosion products for the alloys deposited at a low O2flow rate after 54 days of tarnish testing are mainly composed of brochantite.

Copper-based materials in anode electrode of aqueous zinc metal batteries

Aqueous zinc metal batteries have attracted much attention in the field of large-scale energy storage due to their abundant resources,high safety,low cost,and high theoretical energy density.However,Zn anodes suffer from serious problems such as dendrite growth,hydrogen evolution reaction,corrosion,and passivation.Cu-based materials have a wide range of applications in Zn anodes due to their excellent zincophilicity.Unfortunately,relevant review on Cu-based materials in anode electrode is still lacking.This review focuses on the progress,issues,and optimization strategies of Cu-based materials in Zn anodes.The application of Cu collectors in Zn anodes and the corresponding modifications are also highlighted.Finally,insights and future directions related to Cu-based materials for modified Zn anode and Cu collectors are presented to provide scientific guidance for future research.

Electronic origin of the unusual thermal properties of copper-based semiconductors:The s-d coupling-induced large phonon anharmonicity

Copper(Cu)-based materials(such as cuprates,Cu chalcogenides,and Cu halides)often exhibit unusual properties such as superconductivity,ultralow thermal conductivity,and superionicity.However,the electronic origin of these unusual behaviors remains elusive.In this study,we demonstrate that the high-lying occupied 3d orbital of Cu causes a strong s-d coupling with its unoccupied 4s state when local symmetry is reduced.This leads to strong phonon anharmonicity and is responsible for these intriguing properties.For example,during thermal transport,symmetry-controlled s-d coupling can substantially lower the lattice potential barrier,thereby enhancing the anharmonicity and scattering between phonons and ultimately significantly reducing lattice thermal conductivity.We confirmed this understanding with Raman spectra measurements,which demonstrated a remarkable red shift in the phonon vibrational frequency with an increase in the temperature of Cu-based semiconductors.Our study shows that the cause of phonon anharmonicity is related to the fundamental electronic structures,which can also explain other unusual physical properties of the Cu compounds.

Active site identification and engineering during the dynamic evolution of copper-based catalysts for electrocatalytic CO_(2) reduction

To date,copper-based catalysts are one of the most prominent catalysts that can electrochemically reduce CO_(2)towards highvalue fuels or chemicals,such as ethylene,ethanol,and acetic acid.However,the chemically active feature of Cu-based catalysts hinders the understanding of the intrinsic catalytic active sites during the initial and the operative processes of electrochemical CO_(2)reduction(CO_(2)RR).The identification and engineering of active sites during the dynamic evolution of catalysts are thereby vital to further improve the activity,selectivity,and durability of Cu-based catalysts for high-performance CO_(2)RR.In this regard,four triggers for the dynamic evolution of catalysts were introduced in detail.Afterward,three typical active-site theories during the dynamic reconstruction of catalysts were discussed.In addition,the strategies in catalyst design were summarized according to the latest reports of Cu-based catalysts for CO_(2)RR,including the tuning of electronic structure,controlling of the external potential,and regulation of local catalytic environment.Finally,the conclusions and perspectives were provided to inspire more investigations and studies on the intrinsic active sites during the dynamic evolution of catalysts,which could promote the optimization of the catalyst system to further improve the performance of CO_(2)RR.

Converting industrial waste contact masses into effective multicomponent copper-based catalysts for the Rochow process

In this work, we report a simple and inexpensive approach to synthesize effective multicomponent Cu-Cu2O-CuO catalysts for the Rochow process from industrial waste contact masses （WCMs）. WCMs from the organosilane industry were treated with acid followed by reduction with metallic iron powder. The obtained copper powder was then subjected to controlled oxidation in air at different temperatures, followed by ball milling. The orthogonal array approach was applied to optimize this process, and the stirring speed and pH were found to significantly affect the leaching ratio and copper yield, respectively. When used for the Rochow process, the optimized ternary Cu-Cu2O-CuO catalyst greatly enhanced the dimethyldichlorosilane selectivity and Si conversion compared with Cu-Cu2O-CuO catalysts prepared without ball milling, bare Cu catalysts, and Cu-Cu2O-CuO catalysts with different compositions. This could be attributed to their small particle size and the strong synergistic effect among the multiple components in the catalyst with the optimized composition.

MICROALLOYING EFFECT OF BORON ON COPPER-BASE ALLOYS

The microstructure and properties of boron-modified copper-base alloys were investigated by tension,corrosion,corrosive wear and erosion tests.The results show that by adding boron in copper-base alloys,the strength and hardness of alloys increase,the plasticity decreases somewhat;the corrosion,corrosive wear and erosion resistance of boron-modified copper-base alloys improve obviously.The microalloying mechanism of boron in copper-base alloys was found.

COLOR CHARACTERISTICS OF BINARY COPPER-BASE ALLOYS

The effect of Al, Zn, Sn, Mn, Si and Ni on the color characteristics of binary copper-base alloys has been researched systematically and quantitatively. The results show that all alloying elements decrease the red content of an alloy at different levels but have different effects on the yellow color. Al and Zn enhance the yellow content of an alloy, whereas Sn, Mn, Si and Ni decrease the yellow content. When the alloys with different karat gold colors are imitated, Al and Zn are the most important color mixing elements and Sn, Mn, Si and Ni can be used as auxiliary.

Progress in Processes and Catalysts for Dehydrogenation of Cyclohexanol to Cyclohexanone

The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic reaction is constrained by thermodynamic equilibrium and involves a complex reaction network, leading to a heightened focus on catalysts and process design. Copper-based catalysts have been extensively studied and exhibit exceptional low-temperature catalytic performance in cyclohexanol dehydrogenation, with some being commercially used in the industry. This paper specifically concentrates on research advancement concerning active species, reaction mechanisms, factors influencing product selectivity, and the deactivation behaviors of copper-based catalysts. Moreover, a brief introduction to the new processes that break thermodynamic equilibrium via reaction coupling and their corresponding catalysts is summarized here as well. These reviews may off er guidance and potential avenues for further investigations into catalysts and processes for cyclohexanol dehydrogenation.

Solid solution evolution during mechanical alloying in Cu–Nb–Al compounds

This work concerns the structural evolution of Cu70Nb20Al10(at%) alloy processed by mechanical alloying using a planetary ball mill in air atmosphere for different times(4 to 200 h). The morphological, structural, microstructural, and thermal behaviors of the alloy were investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and differential scanning calorimetry. X-ray diffraction patterns were examined using the Rietveld refinement technique with the help of the MAUD software. A disordered FCC-Cu(Nb,Al) solid solution was formed after 8 h of milling. The crystallite size, microstrain, and lattice parameter were determined by the Rietveld method. With increasing milling time, the crystallite size of the final product-ternary-phase FCC-Cu(Nb,Al)-is refined to the nanometer scale, reaching 12 nm after 200 h. This crystallographic structure combines good mechanical strength and good ductility. An increase in microstrain and partial oxidation were also observed with increasing milling time.

Al_(x)/HKUST-1 prepared by synthetic exchange as catalyst for reduction of NO by CO at low temperature

Al_(x)/HKUST-1(x=1/24,1/12,1/6,1/3),one of the bimetallic copper-based organic framework materials,was successfully prepared by the synthetic exchange method and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),specific surface area(BET),thermogravimetric analysis(TG),infrared spectra(IR),X-ray photoelectron spectroscopy(XPS),and H_(2)-temperature programmed reduction(H_(2)-TPR).The findings indicated that Al_(x)/HKUST-1 maintained the octahedral morphology of its precursor(HKUST-1).The thermal stability and catalytic reduction ability of HKUST-1 skeleton were improved by doping aluminum(Al^(3+)).Al_(1/12)/HKUST-1 showed the best performance among all samples,with a nitric oxide(NO)conversion rate of 100%at 210℃(50℃lower than that of HKUST-1).The valence kind of Al,Cu,and O in Al_(1/12)/HKUST-1 did not change after the catalytic reaction,but the contents of Al,Cu,and O in different forms changed significantly.The catalytic process of the Al_(x)/HKUST-1 followed a Langmuir-Hinshelwood mechanism.

Popping of g-C_3N_4 mixed with cupric nitrate: Facile synthesis of Cu-based catalyst for construction of C-N bond

A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride(C3 N4) was developed by popping of mixture containing C3 N4 and cupric nitrate. Characterizations such as X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) indicate that the structure of g-C3 N4 maintained although a popping process occurred. High resolution transmission electronic microscopy(HRTEM) characterization illustrated that copper-based nanoparticles with diameter of < 1 nm were well distributed on g-C3 N4. This kind of copper catalyst exhibits high catalytic activity and selectivity in arylation of pyrazole, a simple and effect strategy to construct C-N bond in organic chemistry.According to the results of control experiments and characterizations, cuprous oxide should be the catalytic active phase in the supported coperbased catalyst.