Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5(Si/Al ratio=15)with aqueous solutions of differ-ent Cu precursors(CuCl_(2),Cu(NO_(3))2,CuSO_(4),Cu(CH_(3)COO)2,and ammoniacal copper(II)complex ion).After bei...Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5(Si/Al ratio=15)with aqueous solutions of differ-ent Cu precursors(CuCl_(2),Cu(NO_(3))2,CuSO_(4),Cu(CH_(3)COO)2,and ammoniacal copper(II)complex ion).After being pretreated in flowing He at 500℃to form active Cu+,these catalysts exhibited quite different activities in cata-lytic decomposition of N_(2)O.CZM-AC(II)(prepared by ammoniacal copper(II)complex ion)with 9.4 wt%Cu con-tent was the most active among these Cu-ZSM-5 catalysts,achieving almost complete N_(2)I conversion at 400℃.CZM-CA(prepared using Cu(CH_(3)COO)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 N_(2)I conversion at 425℃.CZM-CC,CZM-CN,and CZM-CS prepared by using CuCl_(2),Cu(NO_(3))2,or CuSO_(4)as the Cu precursor with similar Cu contents(≈1.7 wt%)were the least active among these Cu-ZSM-5 catalysts,achieving ca.90%N_(2)O conversion at 500℃.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.展开更多
In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the pr...In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the prepared catalyst fo r CO oxidation were investigated.The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction(XRD),Raman spectroscopy,N_(2)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 H_(2)(H_(2)-TPR).The results show that the CuO-CeO_(2)catalyst prepared with copper acetate as precursor(CC-A) exhibits the best catalytic activity for CO oxidation at low temperatures,with T50and T90values of 62 and 78℃ 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-CeO_(2) catalyst prepared with copper nitrate as precursor(CC-N) displays better stability and resistance to water or CO_(2) poisoning than CC-A.展开更多
According to the principles of simultaneous equilibrium and mass balance,a series of thermodynamic equilibrium equations of Cu2+-C2O42--NH3-NH4+-H2O system at ambient temperature were deduced theoretically and the log...According to the principles of simultaneous equilibrium and mass balance,a series of thermodynamic equilibrium equations of Cu2+-C2O42--NH3-NH4+-H2O system at ambient temperature were deduced theoretically and the logarithm concentration versus pH value(lg[Cu 2+ ]T—pH)diagrams at different solution compositions were drawn.The results show that when pH is below 5.0,copper ion reacts with C2O42-directly and the morphology of copper precursor powder is of pie-shape;when pH is above 5.0,copper ion coordinates with ammonia,and the precipitation proceeds slowly accompanying with the release of copper ions from the multi-coordinated2+ 3Cu(NH) n (n=1,2,···,5)and the morphologies of copper precursor powder are respectively of rod aggregation shape(when 5.0<pH<8.0)and of rod-shape(when pH>8.0).Some experiments were performed to confirm the relation between the total concentration of copper ion and pH value.It is shown that the thermodynamic mathematical model is correct and the calculated values are basically accurate.展开更多
Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportun...Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportunity to modify chemical and physical properties exists. In this paper, a copper-nickel bimetallic nanoalloy film was fabricated by mixing copper and nickel precursor inks and sintering them in vacuum. The individual elemental inks were formulated and characterized using SEM, EDS, and XRD. During thermal processing, elemental copper forms first and is followed by the formation of bimetallic copper-nickel alloy. The encapsulation of the underlying copper by the nickel-rich alloy provides excellent oxidation resistance. No change in film resistance was observed after the film was exposed to an oxygen plasma. Nanoalloy films printed using reactive metallic inks have a variety of important applications involving local control of alloy composition. Examples include facile formation of layered nanostructures, and electrical conductivity with oxidative stability.展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.21477022)
文摘Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5(Si/Al ratio=15)with aqueous solutions of differ-ent Cu precursors(CuCl_(2),Cu(NO_(3))2,CuSO_(4),Cu(CH_(3)COO)2,and ammoniacal copper(II)complex ion).After being pretreated in flowing He at 500℃to form active Cu+,these catalysts exhibited quite different activities in cata-lytic decomposition of N_(2)O.CZM-AC(II)(prepared by ammoniacal copper(II)complex ion)with 9.4 wt%Cu con-tent was the most active among these Cu-ZSM-5 catalysts,achieving almost complete N_(2)I conversion at 400℃.CZM-CA(prepared using Cu(CH_(3)COO)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 N_(2)I conversion at 425℃.CZM-CC,CZM-CN,and CZM-CS prepared by using CuCl_(2),Cu(NO_(3))2,or CuSO_(4)as the Cu precursor with similar Cu contents(≈1.7 wt%)were the least active among these Cu-ZSM-5 catalysts,achieving ca.90%N_(2)O conversion at 500℃.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.
基金Project supported by the National Natural Science Foundation of China (21273150)。
文摘In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the prepared catalyst fo r CO oxidation were investigated.The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction(XRD),Raman spectroscopy,N_(2)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 H_(2)(H_(2)-TPR).The results show that the CuO-CeO_(2)catalyst prepared with copper acetate as precursor(CC-A) exhibits the best catalytic activity for CO oxidation at low temperatures,with T50and T90values of 62 and 78℃ 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-CeO_(2) catalyst prepared with copper nitrate as precursor(CC-N) displays better stability and resistance to water or CO_(2) poisoning than CC-A.
文摘According to the principles of simultaneous equilibrium and mass balance,a series of thermodynamic equilibrium equations of Cu2+-C2O42--NH3-NH4+-H2O system at ambient temperature were deduced theoretically and the logarithm concentration versus pH value(lg[Cu 2+ ]T—pH)diagrams at different solution compositions were drawn.The results show that when pH is below 5.0,copper ion reacts with C2O42-directly and the morphology of copper precursor powder is of pie-shape;when pH is above 5.0,copper ion coordinates with ammonia,and the precipitation proceeds slowly accompanying with the release of copper ions from the multi-coordinated2+ 3Cu(NH) n (n=1,2,···,5)and the morphologies of copper precursor powder are respectively of rod aggregation shape(when 5.0<pH<8.0)and of rod-shape(when pH>8.0).Some experiments were performed to confirm the relation between the total concentration of copper ion and pH value.It is shown that the thermodynamic mathematical model is correct and the calculated values are basically accurate.
文摘Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportunity to modify chemical and physical properties exists. In this paper, a copper-nickel bimetallic nanoalloy film was fabricated by mixing copper and nickel precursor inks and sintering them in vacuum. The individual elemental inks were formulated and characterized using SEM, EDS, and XRD. During thermal processing, elemental copper forms first and is followed by the formation of bimetallic copper-nickel alloy. The encapsulation of the underlying copper by the nickel-rich alloy provides excellent oxidation resistance. No change in film resistance was observed after the film was exposed to an oxygen plasma. Nanoalloy films printed using reactive metallic inks have a variety of important applications involving local control of alloy composition. Examples include facile formation of layered nanostructures, and electrical conductivity with oxidative stability.
