We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while...We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.展开更多
This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized b...This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction （XRD）, Ultraviolet-Visible Diffuse Reflection Spectroscopy （UV-Vis DRS）, X-ray Photoelectron Spectroscopy （XPS）, Scanning Electron Microscopy （SEM）, Energy Dispersive Spectrometry （EDS）, Fourier Transform Infrared Spectroscopic Studies （FT-IR）, and Transmission Electron Microscopy （TEM）. From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region （red shift）, the entry ofCu2 ＋ into Ti02 lattice as a substitution- al dopant and S042- ions were covalently bonded with Ti4＋ on the surface of the copper doped titania respectively. The photocatalytic activity studies were investigated by considering methyl orange （MO） as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.展开更多
Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2...Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2,3,and 5 wt%).Cu-doped ZnO thin films were prepared on p-Si(100)substrate by screen printing method.Cu-doped ZnO/Si films were annealed at different temperatures from 300 to 700°C.In this study,Cu-doped ZnO structures were prepared by a simple precipitation technique,and characterized by various techniques such as XRD(X-ray diffraction)and SEM(scanning electron microscope).The electrical properties of Cu-doped ZnO/Si were measured.It has found that Cu-doped ZnO/Si films can be used as optoelectronic devices.展开更多
In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures...In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures:preparing Ti(OH)_4 doped with copper and synthesizing anatase and rutile TiO_2 doped with copper.Ti(OH)_4 doped with copper could be achieved by hydrolyzing TiCl_4in the mixed solution containing deionized water and copper oxalate.The Ti(OH)_4 doped with copper can be gained successfully by the following procedures:rinsing,drying and vacuum drying.The Ti(OH)_4 doped with copper could be converted into anatase TiO_2 doped with copper and rutile TiO_2 doped with copper by incineration for 4.5 h at 723 and 1 073 K,respectively.Characterizations of anatase TiO_2 doped with copper and rutile TiO_2 doped with copper were determined by X-ray diffraction(XRD) and energy dispersion of X-ray(EDX).Anatase and rutile TiO_2 doped with copper were dissolved in a mixed solution containing isopropanol and diethylamine.Stainless electrode was submerged into with the solutions,the film of TiO_2 was formed by drying the thin layer at a ramp rate of 3℃/min until 373 K,and this temperature was held for 1 h.The temperature of the oven was subsequently increased to a final temperature of 823 K at a ramp rate of 3℃/min,and was held at this value for 1 h.The stainless steel covered with modified TiO_2 film was utilized as the anode.The stainless steel mesh was used as the cathode.The cathode and anode were connected with the source and immersed into the solution with 100 mg/L 4-NP.The whole reaction on photocatalysis was perfectly carried out after ultraviolet radiation and aerator were run.The experimental results showed that:cracking ratio of 4-NP ring,the removal ratio of chemical oxygen demand(COD) and total organic carbon(TOC) were respectively more than 90%,80% and 80% within 2 h.Degradation of 4-NP implied its potential application in associated wastewater.展开更多
The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis ...The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis of AB.Herein,we present a straightforward synthesis method for the Cu_(2)O decorated CoO catalyst derived from ZIF-67 precursors using carbothermal shock(~1 s)in air.The obtained results demonstrate that a small amount of Cu_(2)O doping into CoO synergistically enhances AB hydrolysis,resulting in an almost fivefold increase in turnover frequency(TOF=97 molH_(2)molCoO-1min-1at 298 K).Further studies indicated that the incorporation of Cu_(2)O alters the electronic distribution of the surface of catalysts,introducing more oxygen vacancies and increasing the pyridinic nitrogen content.The increased oxygen vacancies effectively enhanced the adsorption and activation ability of active sites for reactants(H_(2)O and AB),while the targeting effect of pyridinic nitrogen enhances the dispersion of the catalyst.Theoretical analysis reveals that CoO plays a key role in the dissociation of H_(2)O,while minor doping with Cu_(2)O substantially reduces the dissociation energy barrier of AB.This research provides a novel strategy for the design and efficient preparation of AB hydrolysis catalysts for efficient hydrogen production.展开更多
Gold nanoparticles(AuNPs)supported on the Cu-doped LaMnO_(3)perovskites exhibit strong Au-Mn-Cu synergy in the aerobic oxidation of gaseous ethanol to acetaldehyde(AC).The Au/LaMnCuO_(3)catalysts achieve AC yields exc...Gold nanoparticles(AuNPs)supported on the Cu-doped LaMnO_(3)perovskites exhibit strong Au-Mn-Cu synergy in the aerobic oxidation of gaseous ethanol to acetaldehyde(AC).The Au/LaMnCuO_(3)catalysts achieve AC yields exceeding 90%and a space-time yield of 715 g_(AC)g_(AU)^(-1)h^(-1)at 225℃,outperforming reported catalysts.The outstanding performance is attributed to adjacent Cu^(+)and Mn^(2+)ions in the perovskite surface,which,together with nearby AuNPs,contribute to the high activity and stability.The best-performing catalyst contains a Cu/Mn ratio of 1/3 in the perovskite.Doping too much Cu into the perovskite leads to metallic Cu,suppressing catalyst performance.Density functional theory(reaction energetics,electronic structure analysis)and microkinetics simulations aided in understanding the synergy between Cu and Mn and the role of AuNPs.The reaction involves two H abstraction steps:(1)O-H cleavage of adsorbed ethanol by the basic perovskite lattice oxygen atom and(2)α-C-H cleavage by AuNPs,yielding AC and adsorbed water.Molecular O_(2)adsorbs in the oxygen vacancy(O_(V))formed by water removal,generating a peroxide anion(O_(2)^(2-))as the activated oxygen species.In the second part of the catalytic cycle,the basic O_(2)^(2-)species abstracts the H atom from another ethanol molecule,followed byα-C-H cleavage by AuNPs,AC production,and water removal.Water formation in the second part of the catalytic cycle is the rate-controlling step for Au/LaMnO_(3)and Au/LaMnCuO_(3)models.Moderate Cu doping enhances the essential Cu^(+)-OV-Mn^(2+)sites and lowers the barrier for water formation due to the weaker Cu-O bond than the Mn-O bond.In contrast,excessive Cu doping creates unstable Cu^(2+)-O-Cu^(2+)sites and shifts the barrier to theα-C-H cleavage.展开更多
The development of highly active,low-cost,and durable electrocatalysts is crucial for the efficient glycerol oxidation reaction(GOR).Herein,a Cu-doped,self-supported NiCo_(2)O_(4)nanosheet array catalyst grown on nick...The development of highly active,low-cost,and durable electrocatalysts is crucial for the efficient glycerol oxidation reaction(GOR).Herein,a Cu-doped,self-supported NiCo_(2)O_(4)nanosheet array catalyst grown on nickel foam(Cu-NiCo_(2)O_(4)/NF)was fabricated through a simple electrodeposition method followed by thermal annealing.The resulting nanosheet arrays are uniformly anchored on the conductive NF substrate,forming a three-dimensional nanoflower-like architecture that offers abundant accessible active sites and enhanced electronic conductivity.Moreover,Cu doping effectively tailors the electronic structure of NiCo_(2)O_(4),optimizing the adsorption and transformation of key glycerol oxidation intermediates.This synergistic effect significantly lowers charge transfer resistance and promotes rapid electron transport.Benefiting from these structural and electronic advantages,the Cu-NiCo_(2)O_(4)/NF catalyst achieves a current density of 10 mA·cm^(-2)at a low overpotential of 1.22 V vs.reversible hydrogen electrode(RHE).It delivers a remarkable glycerol conversion rate of 90.4%with a formate Faradaic efficiency of 94.3%at 1.35 V vs.RHE.Furthermore,the catalyst exhibits excellent long-term electrochemical durability with sustained catalytic performance during extended operation.This work offers a promising strategy to boost the electrocatalytic activity of NiCo_(2)O_(4)through Cu doping,providing new insights into the design of efficient GOR electrocatalysts and contributing to the high-value utilization of biomass-derived molecules and the advancement of green electrochemic al energ y technologies.展开更多
Metal-organic framework（MOF） material MIL-53（A1） with high thermal stability was prepared by a solvothermal method,serving as a support material of cerium doped copper catalyst（Ce-Cu）/MIL-53（A1） material for C...Metal-organic framework（MOF） material MIL-53（A1） with high thermal stability was prepared by a solvothermal method,serving as a support material of cerium doped copper catalyst（Ce-Cu）/MIL-53（A1） material for CO oxidation with high catalytic activity.The catalytic performance between the（CuCe）/MIL-53（A1） and the Cu/MIL-53（A1） catalytic material was compared to understand the catalytic behavior of the catalysts.The catalysts were characterized by thermogravimetric-differential scanning calorimetry（TGDSC）,N2 adsorption- desorption,X-ray diffraction（XRD）,and transmission electron microscopy（TEM）.The characterization results showed that MIL-53（A1） had good stability and high surface areas,the（Ce-Cu）nanoparticles on the MIL-53（A1） support was uniform.Therefore,the heterogeneous catalytic composite materials（Ce-Cu）/MIL-53（A1） catalyst exhibited much higher activity than that of the Cu/MIL- 53（A1） catalyst in CO oxidation test,with 100%conversion at 80 ℃.The results reveal that（Cu-Ce）/MIL-53（A1） is the suitable candidate for achieving low temperature and higher activity CO oxidation catalyst of MOFs.展开更多
The structural and magnetic properties of the Cu-doped ZnO（ZnO：Cu） under c-axis pressure were studied using first-principle calculations. It was found that the ZnO：Cu undergoes a structural transition from Wurtzit...The structural and magnetic properties of the Cu-doped ZnO（ZnO：Cu） under c-axis pressure were studied using first-principle calculations. It was found that the ZnO：Cu undergoes a structural transition from Wurtzite to Graphite-like structure at a c-axis pressure of 7–8 GPa. This is accompanied by an apparent loss of ferromagnetic stability, indicating a magnetic transformation from a ferromagnetic state to a paramagnetic-like state. Further studies revealed that the magnetic instability is closely related to the variation in crystalline field originated from the structural transition, which is in association with the overlapping of spin–charge density between the Cu^2＋ and adjacent O^2-.展开更多
In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited...In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited oxygen reduction rate and easy C-C cleavage.Given the high economic feasibility of nonnoble metals,i.e.,Cu,in this work,copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles(Cu@Cu-N-C)were developed to realize highly selective of PDO oxidation to LA.The carbon-encapsulated ultrasmall Cu^(0)NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu(Cu-N)sites are responsible for the high oxygen reduction efficacy.Therefore,the performance of catalytic PDO conversion to LA is optimized by a proposed pathway of PDO→hydroxylacetone→lactaldehyde→LA.Specifically,the enhanced LA selectivity is 88.5%,and the PDO conversion is up to 75.1%in an O_(2)-pressurized reaction system(1.0 MPa O_(2)),superior to other Cu-based catalysts,while in a milder nonpressurized system(O_(2)flow rate of 100 mL min-1),a remarkable LA selectivity(94.2%)is obtained with 39.8%PDO conversion,2.2 times higher than that of supported Au nanoparticles(1%Au/C).Moreover,carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.展开更多
Iron plays a crucial role in improving the oxygen evolution reaction(OER)activity of hydroxide materials.Increasing the number of iron active sites at the solid–liquid interface is beneficial to enhancing the OER per...Iron plays a crucial role in improving the oxygen evolution reaction(OER)activity of hydroxide materials.Increasing the number of iron active sites at the solid–liquid interface is beneficial to enhancing the OER performance of catalysts but still challenging.Here,by systematic exploring the activity trends of M(OH)_(x)and Cu-M(OH)_(x)(M=Mn,Cu,Ni,Fe,and Co),we discover that the Cu doping can promote the deposition of Fe active sites on metal hydroxide and Cu-Co(OH)2 shows the most favorable iron adsorption capacity.When loaded on a conductive substrate(cobalt foam(CF),the M-Cu-Co(OH)2/CF(Co(OH)_(2))prepared by molten salt method)exhibits an attractive low overpotential of 337 mV at 1,000 mA·cm^(−2).Using in anion exchange membrane(AEM)water electrolyzer,the single cell with M-Cu-Co(OH)_(2)/CF as anode catalyst performs a stable cell voltage of 2.02 V to reach 1,000 mA·cm^(−2)over 24 h,indicating a great application potential for actual electrolytic water.Therefore,the promoted adsorption of copper on iron provides a new perspective for further enhancing the OER activity of other metal hydroxides.展开更多
The electronic properties of Cu-doped lithium niobate(LiNbO_(3))systems are investigated by first-principles calculations.In this work,we focus on substitutionally Cu→Li-doped LiNbO_(3) system with cuprous and cupric...The electronic properties of Cu-doped lithium niobate(LiNbO_(3))systems are investigated by first-principles calculations.In this work,we focus on substitutionally Cu→Li-doped LiNbO_(3) system with cuprous and cupric doping,which corresponds to the Li_(5/6)Cu_(1/6)NbO_(3) and Li_(4/6)Cu_(1/6)NbO_(3)[abbreviated as(Li,Cu Ⅰ)NbO_(3) and(Li,Cu Ⅱ)NbO_(3)].The density functional theory(DFT)calculations show that the electronic property of LiNbO_(3) is completely different from(Li,Cu Ⅰ)NbO_(3) and(Li,Cu Ⅱ)NbO_(3).The calculated band structure and density of state(DOS)of(Li,Cu Ⅰ)NbO_(3) show a small band gap of 1.34 eV and the top of valance band(VB)is completely composed of a doping energy level originating from Cu 3d filled orbital.However,the calculated band structure and DOS of(Li,Cu Ⅱ)NbO_(3) show a relatively large band gap of 2.22 eV and the top of VB is mainly composed of Cu 3d unfilled orbital and O 2p orbital.展开更多
O_(x)idative couplings of aliphatic alkynes are crucial for the production of naturally occurring 1,3-diynes.Herein we report the novel approach for effective synthesis of unsaturated coordinated N doped copper oxides...O_(x)idative couplings of aliphatic alkynes are crucial for the production of naturally occurring 1,3-diynes.Herein we report the novel approach for effective synthesis of unsaturated coordinated N doped copper oxides(N-CuO_(x))catalyst,and uncover that N-CuO_(x) catalyst as an additive-free and cost-effective heterogeneous catalyst has highly catalytic performance for directly oxidative coupling of aliphatic alkynes.The key to achieve efficient oxidative coupling of aliphatic alkynes is the synergistic effect of N species and uncoordinated O/Cu species caused by N dopants,which undergoes the Langmuir–Hinshelwood reaction mechanism.The N-CuO_(x) catalyst displays~89.1%yield for hexadeca-7,9-diyne under mild conditions and stable reusability(5 cycles),showing significant advances compared with the traditionally copper oxides.These findings highlight the heteroatom dopants that provide a new methodology for designing efficient copper catalysts in synthesis of naturally occurring 1,3-diynes.展开更多
基金the National Key Research and Development Program on Nano Science and Technology of the Ministry of Science and Technology of China(No.2016YFA0200602 and No.2018YFA0208702)the National Natural Science Foundation of China(No.21573211 and No.21633007)the Anhui Initiative in Quantum Information Technologies(No.AHY090200)。
文摘We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.
文摘This paper reports on the synthesis of copper doped sulfated titania nano-crystalline powders with varying （2.0%-10.0%, by mass） by single step sol gel method. The synthesized photo catalyst has been characterized by employing various techniques like X-ray Diffraction （XRD）, Ultraviolet-Visible Diffuse Reflection Spectroscopy （UV-Vis DRS）, X-ray Photoelectron Spectroscopy （XPS）, Scanning Electron Microscopy （SEM）, Energy Dispersive Spectrometry （EDS）, Fourier Transform Infrared Spectroscopic Studies （FT-IR）, and Transmission Electron Microscopy （TEM）. From the XRD and TEM results, all the samples were reported in anatase phase with reduction in particle size in the range of 7 to 12 nm. SEM indicated the change in morphology of the particles. The presence of copper in titania lattice was evidenced by XPS. From UV-Vis DRS and FT-IR studies indicated that prominent absorption shift is observed towards visible region （red shift）, the entry ofCu2 ＋ into Ti02 lattice as a substitution- al dopant and S042- ions were covalently bonded with Ti4＋ on the surface of the copper doped titania respectively. The photocatalytic activity studies were investigated by considering methyl orange （MO） as dye pollutant in the presence of the visible light. The effect of various parameters like effect of dosage of the catalyst, dopant concentration, pH of the solution, and concentration of the dye was studied in detail.
文摘Cu(copper)-doped ZnO(zinc oxide)was synthesized using Cu(NO3)2·3H2O(copper(II)nitrate)and Zn(NO3)2·6H2O(zinc nitrate)by chemical co-precipitation method.The weight percentages of dopant in solution were Cu(2,3,and 5 wt%).Cu-doped ZnO thin films were prepared on p-Si(100)substrate by screen printing method.Cu-doped ZnO/Si films were annealed at different temperatures from 300 to 700°C.In this study,Cu-doped ZnO structures were prepared by a simple precipitation technique,and characterized by various techniques such as XRD(X-ray diffraction)and SEM(scanning electron microscope).The electrical properties of Cu-doped ZnO/Si were measured.It has found that Cu-doped ZnO/Si films can be used as optoelectronic devices.
基金Environmental Protection Department of Jiangsu Province,China(No.2013023)Jiangsu Key Laboratory of Industrial Water-Conservation & Emission Reduction,China(No.IWCER201202)
文摘In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures:preparing Ti(OH)_4 doped with copper and synthesizing anatase and rutile TiO_2 doped with copper.Ti(OH)_4 doped with copper could be achieved by hydrolyzing TiCl_4in the mixed solution containing deionized water and copper oxalate.The Ti(OH)_4 doped with copper can be gained successfully by the following procedures:rinsing,drying and vacuum drying.The Ti(OH)_4 doped with copper could be converted into anatase TiO_2 doped with copper and rutile TiO_2 doped with copper by incineration for 4.5 h at 723 and 1 073 K,respectively.Characterizations of anatase TiO_2 doped with copper and rutile TiO_2 doped with copper were determined by X-ray diffraction(XRD) and energy dispersion of X-ray(EDX).Anatase and rutile TiO_2 doped with copper were dissolved in a mixed solution containing isopropanol and diethylamine.Stainless electrode was submerged into with the solutions,the film of TiO_2 was formed by drying the thin layer at a ramp rate of 3℃/min until 373 K,and this temperature was held for 1 h.The temperature of the oven was subsequently increased to a final temperature of 823 K at a ramp rate of 3℃/min,and was held at this value for 1 h.The stainless steel covered with modified TiO_2 film was utilized as the anode.The stainless steel mesh was used as the cathode.The cathode and anode were connected with the source and immersed into the solution with 100 mg/L 4-NP.The whole reaction on photocatalysis was perfectly carried out after ultraviolet radiation and aerator were run.The experimental results showed that:cracking ratio of 4-NP ring,the removal ratio of chemical oxygen demand(COD) and total organic carbon(TOC) were respectively more than 90%,80% and 80% within 2 h.Degradation of 4-NP implied its potential application in associated wastewater.
基金financially supported by the National Natural Science Foundation of China(No.52301276)Zhejiang Provincial Natural Science Foundation of China(No.24E010001)+2 种基金Lishui Science and Technology Plan Project(No.2023GYX09)the support of the National Natural Science Foundation of China(52371229)Shanghai High-level Talent start funding
文摘The high hydrogen desorption density(19.6 wt%)of ammonia borane(AB)makes it one of the most promising chemical hydrogen storage materials.Developing cost-effective catalysts is the key for accelerating the hydrolysis of AB.Herein,we present a straightforward synthesis method for the Cu_(2)O decorated CoO catalyst derived from ZIF-67 precursors using carbothermal shock(~1 s)in air.The obtained results demonstrate that a small amount of Cu_(2)O doping into CoO synergistically enhances AB hydrolysis,resulting in an almost fivefold increase in turnover frequency(TOF=97 molH_(2)molCoO-1min-1at 298 K).Further studies indicated that the incorporation of Cu_(2)O alters the electronic distribution of the surface of catalysts,introducing more oxygen vacancies and increasing the pyridinic nitrogen content.The increased oxygen vacancies effectively enhanced the adsorption and activation ability of active sites for reactants(H_(2)O and AB),while the targeting effect of pyridinic nitrogen enhances the dispersion of the catalyst.Theoretical analysis reveals that CoO plays a key role in the dissociation of H_(2)O,while minor doping with Cu_(2)O substantially reduces the dissociation energy barrier of AB.This research provides a novel strategy for the design and efficient preparation of AB hydrolysis catalysts for efficient hydrogen production.
文摘Gold nanoparticles(AuNPs)supported on the Cu-doped LaMnO_(3)perovskites exhibit strong Au-Mn-Cu synergy in the aerobic oxidation of gaseous ethanol to acetaldehyde(AC).The Au/LaMnCuO_(3)catalysts achieve AC yields exceeding 90%and a space-time yield of 715 g_(AC)g_(AU)^(-1)h^(-1)at 225℃,outperforming reported catalysts.The outstanding performance is attributed to adjacent Cu^(+)and Mn^(2+)ions in the perovskite surface,which,together with nearby AuNPs,contribute to the high activity and stability.The best-performing catalyst contains a Cu/Mn ratio of 1/3 in the perovskite.Doping too much Cu into the perovskite leads to metallic Cu,suppressing catalyst performance.Density functional theory(reaction energetics,electronic structure analysis)and microkinetics simulations aided in understanding the synergy between Cu and Mn and the role of AuNPs.The reaction involves two H abstraction steps:(1)O-H cleavage of adsorbed ethanol by the basic perovskite lattice oxygen atom and(2)α-C-H cleavage by AuNPs,yielding AC and adsorbed water.Molecular O_(2)adsorbs in the oxygen vacancy(O_(V))formed by water removal,generating a peroxide anion(O_(2)^(2-))as the activated oxygen species.In the second part of the catalytic cycle,the basic O_(2)^(2-)species abstracts the H atom from another ethanol molecule,followed byα-C-H cleavage by AuNPs,AC production,and water removal.Water formation in the second part of the catalytic cycle is the rate-controlling step for Au/LaMnO_(3)and Au/LaMnCuO_(3)models.Moderate Cu doping enhances the essential Cu^(+)-OV-Mn^(2+)sites and lowers the barrier for water formation due to the weaker Cu-O bond than the Mn-O bond.In contrast,excessive Cu doping creates unstable Cu^(2+)-O-Cu^(2+)sites and shifts the barrier to theα-C-H cleavage.
基金supported by the National Natural Science Foundation of China(No.22302051)Hainan Provincial Natural Science Foundation of China(No.223QN186)+1 种基金Scientific Research Starting Foundation of Hainan University(No.KYQD(ZR)-22018)the specific research fund of the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202123)。
文摘The development of highly active,low-cost,and durable electrocatalysts is crucial for the efficient glycerol oxidation reaction(GOR).Herein,a Cu-doped,self-supported NiCo_(2)O_(4)nanosheet array catalyst grown on nickel foam(Cu-NiCo_(2)O_(4)/NF)was fabricated through a simple electrodeposition method followed by thermal annealing.The resulting nanosheet arrays are uniformly anchored on the conductive NF substrate,forming a three-dimensional nanoflower-like architecture that offers abundant accessible active sites and enhanced electronic conductivity.Moreover,Cu doping effectively tailors the electronic structure of NiCo_(2)O_(4),optimizing the adsorption and transformation of key glycerol oxidation intermediates.This synergistic effect significantly lowers charge transfer resistance and promotes rapid electron transport.Benefiting from these structural and electronic advantages,the Cu-NiCo_(2)O_(4)/NF catalyst achieves a current density of 10 mA·cm^(-2)at a low overpotential of 1.22 V vs.reversible hydrogen electrode(RHE).It delivers a remarkable glycerol conversion rate of 90.4%with a formate Faradaic efficiency of 94.3%at 1.35 V vs.RHE.Furthermore,the catalyst exhibits excellent long-term electrochemical durability with sustained catalytic performance during extended operation.This work offers a promising strategy to boost the electrocatalytic activity of NiCo_(2)O_(4)through Cu doping,providing new insights into the design of efficient GOR electrocatalysts and contributing to the high-value utilization of biomass-derived molecules and the advancement of green electrochemic al energ y technologies.
基金Funded by the Guiding Research Project of Hubei Province Department of Education(No.B2016098)
文摘Metal-organic framework（MOF） material MIL-53（A1） with high thermal stability was prepared by a solvothermal method,serving as a support material of cerium doped copper catalyst（Ce-Cu）/MIL-53（A1） material for CO oxidation with high catalytic activity.The catalytic performance between the（CuCe）/MIL-53（A1） and the Cu/MIL-53（A1） catalytic material was compared to understand the catalytic behavior of the catalysts.The catalysts were characterized by thermogravimetric-differential scanning calorimetry（TGDSC）,N2 adsorption- desorption,X-ray diffraction（XRD）,and transmission electron microscopy（TEM）.The characterization results showed that MIL-53（A1） had good stability and high surface areas,the（Ce-Cu）nanoparticles on the MIL-53（A1） support was uniform.Therefore,the heterogeneous catalytic composite materials（Ce-Cu）/MIL-53（A1） catalyst exhibited much higher activity than that of the Cu/MIL- 53（A1） catalyst in CO oxidation test,with 100%conversion at 80 ℃.The results reveal that（Cu-Ce）/MIL-53（A1） is the suitable candidate for achieving low temperature and higher activity CO oxidation catalyst of MOFs.
基金supported by the National Natural Science Foundation of China(Grant Nos.51031004 and 51272078)the Natural Science Foundation of Guangdong,China(Grant No.S2012010008124)+3 种基金the National Basic Research Program of China(Grant No.2015CB921202)the Project for Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2014)International Science & Technology Cooperation Platform Program of Guangzhou,China(Grant No.2014J4500016)the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(Grant No.IRT1243)
文摘The structural and magnetic properties of the Cu-doped ZnO（ZnO：Cu） under c-axis pressure were studied using first-principle calculations. It was found that the ZnO：Cu undergoes a structural transition from Wurtzite to Graphite-like structure at a c-axis pressure of 7–8 GPa. This is accompanied by an apparent loss of ferromagnetic stability, indicating a magnetic transformation from a ferromagnetic state to a paramagnetic-like state. Further studies revealed that the magnetic instability is closely related to the variation in crystalline field originated from the structural transition, which is in association with the overlapping of spin–charge density between the Cu^2＋ and adjacent O^2-.
基金supported by the National Natural Science Foundation of China(32371407,82160421)the Natural Science Foundation of Jiangsu Province(BK20211322)。
文摘In the selective oxidation of biomass-based 1,2-propanediol(PDO)with oxygen as the terminal oxidant,it is challenging to improve the lactic acid(LA)selectivity for nonnoble metal nanoparticles(NPs)due to their limited oxygen reduction rate and easy C-C cleavage.Given the high economic feasibility of nonnoble metals,i.e.,Cu,in this work,copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles(Cu@Cu-N-C)were developed to realize highly selective of PDO oxidation to LA.The carbon-encapsulated ultrasmall Cu^(0)NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu(Cu-N)sites are responsible for the high oxygen reduction efficacy.Therefore,the performance of catalytic PDO conversion to LA is optimized by a proposed pathway of PDO→hydroxylacetone→lactaldehyde→LA.Specifically,the enhanced LA selectivity is 88.5%,and the PDO conversion is up to 75.1%in an O_(2)-pressurized reaction system(1.0 MPa O_(2)),superior to other Cu-based catalysts,while in a milder nonpressurized system(O_(2)flow rate of 100 mL min-1),a remarkable LA selectivity(94.2%)is obtained with 39.8%PDO conversion,2.2 times higher than that of supported Au nanoparticles(1%Au/C).Moreover,carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.
基金supported by the National Natural Science Foundation of China(No.52174283)Innovation Fund Project for Graduate Student of China University of Petroleum(East China)(No.22CX04026A)the Fundamental Research Funds for the Central Universities.
文摘Iron plays a crucial role in improving the oxygen evolution reaction(OER)activity of hydroxide materials.Increasing the number of iron active sites at the solid–liquid interface is beneficial to enhancing the OER performance of catalysts but still challenging.Here,by systematic exploring the activity trends of M(OH)_(x)and Cu-M(OH)_(x)(M=Mn,Cu,Ni,Fe,and Co),we discover that the Cu doping can promote the deposition of Fe active sites on metal hydroxide and Cu-Co(OH)2 shows the most favorable iron adsorption capacity.When loaded on a conductive substrate(cobalt foam(CF),the M-Cu-Co(OH)2/CF(Co(OH)_(2))prepared by molten salt method)exhibits an attractive low overpotential of 337 mV at 1,000 mA·cm^(−2).Using in anion exchange membrane(AEM)water electrolyzer,the single cell with M-Cu-Co(OH)_(2)/CF as anode catalyst performs a stable cell voltage of 2.02 V to reach 1,000 mA·cm^(−2)over 24 h,indicating a great application potential for actual electrolytic water.Therefore,the promoted adsorption of copper on iron provides a new perspective for further enhancing the OER activity of other metal hydroxides.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China under Grant No.20120201130004Research Start-up Funds Doctor of Guilin University of Technology(No.GUTQDJJ2017133)。
文摘The electronic properties of Cu-doped lithium niobate(LiNbO_(3))systems are investigated by first-principles calculations.In this work,we focus on substitutionally Cu→Li-doped LiNbO_(3) system with cuprous and cupric doping,which corresponds to the Li_(5/6)Cu_(1/6)NbO_(3) and Li_(4/6)Cu_(1/6)NbO_(3)[abbreviated as(Li,Cu Ⅰ)NbO_(3) and(Li,Cu Ⅱ)NbO_(3)].The density functional theory(DFT)calculations show that the electronic property of LiNbO_(3) is completely different from(Li,Cu Ⅰ)NbO_(3) and(Li,Cu Ⅱ)NbO_(3).The calculated band structure and density of state(DOS)of(Li,Cu Ⅰ)NbO_(3) show a small band gap of 1.34 eV and the top of valance band(VB)is completely composed of a doping energy level originating from Cu 3d filled orbital.However,the calculated band structure and DOS of(Li,Cu Ⅱ)NbO_(3) show a relatively large band gap of 2.22 eV and the top of VB is mainly composed of Cu 3d unfilled orbital and O 2p orbital.
基金supported by the“Key Program for International S&T Cooperation Projects of China”(No.2017YFE0124300)Anhui Provincial Natural Science Foundation of China(No.2008085M47)+1 种基金Key Projects of the Department of Education of Anhui Province of China(No.RZ2000003450)The authors thank the beamline BL14W1 at Shanghai Synchrotron Radiation Facility(SSRF).
文摘O_(x)idative couplings of aliphatic alkynes are crucial for the production of naturally occurring 1,3-diynes.Herein we report the novel approach for effective synthesis of unsaturated coordinated N doped copper oxides(N-CuO_(x))catalyst,and uncover that N-CuO_(x) catalyst as an additive-free and cost-effective heterogeneous catalyst has highly catalytic performance for directly oxidative coupling of aliphatic alkynes.The key to achieve efficient oxidative coupling of aliphatic alkynes is the synergistic effect of N species and uncoordinated O/Cu species caused by N dopants,which undergoes the Langmuir–Hinshelwood reaction mechanism.The N-CuO_(x) catalyst displays~89.1%yield for hexadeca-7,9-diyne under mild conditions and stable reusability(5 cycles),showing significant advances compared with the traditionally copper oxides.These findings highlight the heteroatom dopants that provide a new methodology for designing efficient copper catalysts in synthesis of naturally occurring 1,3-diynes.
