Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from th...Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.展开更多
The CuxO-CeO2/Fe@CNSs, CuxO-CeO2/MWCNTs-Co and CuxO-CeO2/MWCNTs-Ni catalysts were prepared by the impregnation method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder d...The CuxO-CeO2/Fe@CNSs, CuxO-CeO2/MWCNTs-Co and CuxO-CeO2/MWCNTs-Ni catalysts were prepared by the impregnation method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, H2-temperature programmed reduction and N2 adsorption-desorption techniques. It was found that the Fe nanoparticles were encapsulated into the multi-layered carbon nanospheres （CNSs）. However, the multi-wall carbon nanotubes （MWCNTS） were generated on the Co/Al2O3 and Ni/Al2O3 precursor. The addition of carbon nanomaterial as supports could improve structural properties and low-temperature activity of the CuO-CeO2 catalyst, and save the used amount of metal catalysts in the temperature range with high selectivity for CO oxidation. The copper-cerium oxides supported on carbon nanomaterial had good resistence to H2O and CO2.展开更多
A microreactor system and TPD techniques were used to study the reaction kinetics of the CO+ NO reaction and the adsorption of CO,NO,CO_2 and N_2O over Cu-Mn-O(Ⅰ)and Cu-Mn-Ce-O(Ⅱ) catalysts.The results show that the...A microreactor system and TPD techniques were used to study the reaction kinetics of the CO+ NO reaction and the adsorption of CO,NO,CO_2 and N_2O over Cu-Mn-O(Ⅰ)and Cu-Mn-Ce-O(Ⅱ) catalysts.The results show that the catalytic activity of(Ⅱ)is higher than that of(Ⅰ)for the CO+NO reac- tion,and the higher the conversion of NO,the larger was the activity difference between(Ⅰ)and(Ⅱ).For (Ⅰ)the rate of NO elimination is dependent on the partial pressures of NO,CO,CO_2 with the kinetics or- ders of 0.48,0.56,0.08,respectively.The TPD study shows that the presence of Ce in(Ⅱ)may promote the adsorption of NO,CO on the surface,i.e.an increase of the coverage θ_(NO),θ_(CO),which result in a decrease of the hindrance of the reaction products.For CO_2 and N_2O the situation is in the opposite,the presence of Ce makes the θ_(CO)_2)and θ_(NO)on(Ⅱ)decrease,which weakens the inhibition of CO_2 for the reaction.展开更多
Pt-based methanol oxidation reaction(MOR)electrocatalysts with high activity,stability,and carbon monoxide(CO)tolerance are critical for advancing direct methanol fuel cells(DMFC).Herein,a low-Pt-content electrocataly...Pt-based methanol oxidation reaction(MOR)electrocatalysts with high activity,stability,and carbon monoxide(CO)tolerance are critical for advancing direct methanol fuel cells(DMFC).Herein,a low-Pt-content electrocatalyst(Pt/CeO_(2)-carbon nanofiber(CNF))is developed through electrospinning,high-temperature calcination,and sodium borohydride(NaBH_(4))reduction,featuring highly dispersed Pt nanoparticles anchored on oxygen vacancy(Ov)-rich CeO_(2) embedded within CNF.The strong metal–support interaction(SMSI)induces Pt–O–Ce interfacial bonding,facilitating electron transfer and enhancing MOR performance.Pt/CeO_(2)-CNF achieves a mass activity of 5.29 A·mgPt^(-1),3.5 times higher than commercial Pt/C,alongside exceptional stability(92%retention after 1000 cycles)and CO tolerance.When deployed as a DMFC anode,it delivers a peak power density of 34.72 mW·cm^(-2),outperforming Pt/C by 31%.Characterization results indicate that SMSI induces charge redistribution between Pt and CeO_(2),which synergistically enhances the reaction kinetics of MOR with the hydroxyl groups produced by CeO_(2) hydrolysis.In addition,the uniform dispersion of in-situ grown CeO_(2) is ensured on CNF,and Ov acts as an anchoring point to stabilize Pt nanoparticles,improving the stability of the catalyst.This work establishes a design framework for synthesizing high-performance Pt-based DMFC electrocatalysts through controlled structural and electronic modulation strategies.展开更多
A microreactor system was used to study the catalytic reaction of NO+CO→1/2 N_2+CO_2 over Cu,Fe, Mn,Cr,and Ce oxides supported on alumina,and the effect of adding Ce in supported Cu-M-O(M=Mn,Fe and Cr) catalysts on t...A microreactor system was used to study the catalytic reaction of NO+CO→1/2 N_2+CO_2 over Cu,Fe, Mn,Cr,and Ce oxides supported on alumina,and the effect of adding Ce in supported Cu-M-O(M=Mn,Fe and Cr) catalysts on their catalytic activities for the topic reaction and the concentration of N_2O produced.It was found that the catalytic activity order of the single-element oxide is:CuO>Fe_2O_3≈Cr_2O_3> MnO_2>CeO_2>NiO.Cu-Mn-O is more active than CuO,and Cu-Fe-O is more active than Cu-Mn-O and Cu-Cr-O for NO+CO reaction.This study shows that the addition of Ce in supported Cu-M-O can promote their catalytic activities Jot the topic reaction,which makes the reaction of 2NO+CO→N_2O+CO_2 fast,and N_2O is an intermediate compound produced during NO+CO reaction.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
Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400...Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400 mg/L of ammonia were oxidized in a batch-bed reac-tor with a catalyst prepared by the co-precipitation of copper nitrate, lanthanum nitrate and cerium nitrate. Barely any of the dissolved ammo-nia was removed by wet oxidation without a catalyst, but about 88% of the ammonia was reduced during wet oxidation over the catalysts at 423 K with an oxygen partial pressure of 4.0 MPa. The catalytic redox behavior was determined by cyclic voltammetry （CV）. Furthermore, the catalysts were characterized using thermogravimetric analyzer （TGA） and scanning electron microscope-energy dispersive X-ray spectroscopy （SEM-EDX）, which showed that the catalytic behavior was related to the metal oxide properties of the catalyst. In addition, the copper-lanthanum-cerium composite-induced cytotoxicity in the human lung MRC-5 cell line was tested, and the percentage cell survival was determined by 3-（4,5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetra-zolium （MTS） analysis in vitro. No ap-parent cytotoxicity was observed when the human lung cells were exposed to the copper-lanthanum-cerium composite.展开更多
At present,the problem of air pollution facing the earth is becoming more and more severe,and it has become an urgent task for researchers to find effective solutions.As an important catalyst carrier and active compon...At present,the problem of air pollution facing the earth is becoming more and more severe,and it has become an urgent task for researchers to find effective solutions.As an important catalyst carrier and active component,CeO_(2)has received extensive attention in the field of CO-catalyzed oxidation.This article reviews the strategies of doping metal active components,regulating the loaded active sites and controlling the preferential exposure of crystal planes as approaches to enhance the low-temperature oxidation activity of CO.When the active metal is incorporated into the CeO_(2)lattice,the active metal significantly reduces the oxygen vacancy formation energy(Evf)on the catalyst surface,resulting in the high catalytic activity of the catalyst at low temperatures.When the active metal is loaded on the CeO_(2)surface,many active sites can be obtained by increasing the dispersion,and the catalytic activity can be significantly improved by introducing new interface sites between the metal and the CeO_(2)support.By precisely controlling the arrangement of surface atoms,the reactivity of Ce^(4+)/Ce^(3+)ions can be effectively regulated,thereby altering the oxygen release and absorption properties of CeO_(2).This review is helpful for the application of CeO_(2)-containing catalysts in the field of low-temperature catalytic oxidation of CO.展开更多
Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found...Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found±at graphene oxide(GO)can enhance the degradation efficiency of micropollutants during ozonation.However,in this study,GO was found to promote bromate formation during ozonation of bromide-containing waters,with bromate yields from the O3/GO process more than twice those obtained using ozone alone.The promoted bromate formation was attributed to increased hydroxyl radical production,as confirmed by the significant reduction(almost 75%)in bromate yield after adding t-butanol(TBA).Cerium oxide(less tfian 5 mg/L)supported on reduced GO(xCeO2/RGO)significantly inhibited bromate formation during ozonation compared with reduced GO alone,and the optimal Ce atomic percentage(x)was determined to be 0.36%,achieving an inhibition rate of approximately 73%.Fourier transform infrared(FT-IR)spectra indicated the transformation of GO into RGO after hydrothermal treatment,and transmission electron microscope(TEM)results showed that CeO2 nanoparticles were well dispersed on the RGO surface.The X-ray photoelectron spectroscopy(XPS)spectra results demonstrated that the Ce^3+/Ce^4+ratio in xCeO2/RGO was almost 3-4 times higher than that in pure CeO2,which might be attributed to the charge transfer effect from GO to CeO2.Furthermore,Ce+on thexCeO2/RGO surface could quench Br-and BrO-to further inhibit bromate formation.Meanwhile,0.36CeO2/RGO could also enhance the degradation efficiency of N,N-diethyl-zn-toluamide(DEET)in synthetic and reclaimed water during ozonation.展开更多
Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impre...Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impregnation method to ensure uniform distribution of cerium and copper nitrates within the structure of coal powdery samples (according to SEM and EDX mapping). The samples reactivity was studied in an isothermal oxidation regime at 200 °C (1 h) and by DSC/TGA at 2.5 °C/min heating rate. The additives implementation was found to reduce significantly the oxidation onset temperature (△Ti = 20-55 °C), the samples oxidation delay time (△ti= 2-22 min) and overall duration of the oxidation process (△tc = 8-16 min). The additives efficiency could be graded in accordance with the activation on the coal oxidation in the following row: Cu(NO3)2 >{Cu(NO3)2 + Ce(NO3)3}> Ce(NO3)3. According to the mass spectroscopy, the obtained row of activation correlates well with the initial temperature of the studied nitrate's decomposition (from 190 to 223 °C). A presence of nitrates was found to change significantly the trend of heat release taking place during the oxidation of coal samples (according to DSC/TGA data). The influence of coal morphology and volatiles concern in initial sample on the parameters of the oxidation process was studied as well. Activation energy (Ea) of the coal oxidation was calculated using Coats-Redfern method. Maximum decrease in Ea from 69 to 58 kJ/mol was observed for the samples with Cu(NO3)2. Graphical abstract.展开更多
CeO2-ZrO2 mixed oxide （Ce0.6Zr0.402） prepared by microwave-assisted heating co-precipitation was used as a support to prepare a series of CuO/Ce0.6Zr0.402 catalysts with various CuO contents （0 wt.%-1 5 wt.%） via ...CeO2-ZrO2 mixed oxide （Ce0.6Zr0.402） prepared by microwave-assisted heating co-precipitation was used as a support to prepare a series of CuO/Ce0.6Zr0.402 catalysts with various CuO contents （0 wt.%-1 5 wt.%） via the method of incipient-wetness im- pregnation. The obtained CuO/Ce0.6Zr0.402 samples were characterized by N2 adsorption, XRD, Raman, TEM and H2-TPR technolo- gies, and their catalytic activities for CO oxidation were investigated. The results showed that the activity of CuO/Ce0.6Zr0.402 catalyst was strongly influenced by the content of CuO, and the catalyst with 10 wt.% CuO exhibited the best catalytic activity in CO oxida- tion, which could be attributed to the high dispersion and reducibility of CuO, and high oxygen vacancy concentration in the catalyst.展开更多
The CeO2/CuO catalysts using different template agent（F68 L64, F127 and P123） were synthesized by the simple template and impregnation method. They were characterized by FESEM, XRD, N2 physisorption and H2-TPR techn...The CeO2/CuO catalysts using different template agent（F68 L64, F127 and P123） were synthesized by the simple template and impregnation method. They were characterized by FESEM, XRD, N2 physisorption and H2-TPR techniques. It is found that the CeO2/CuO catalysts are double pore distribution, and CeO2 can enter into the gap of CuO supports and form the contact interface of copper and cerium. Among the asprepared catalysts, the CeO2/CuO-F127 catalyst displays better activity at lower temperature and the CeO2/CuO-P123 catalyst presents higher activity at higher temperature. The CeO2/CuO-P123 catalyst has the smallest crystallite sizes of CuO and CeO2 as well as the largest size of cubes, which may improve the interaction of copper and cerium and enhance the performance of CO oxidation.展开更多
Carbon dioxide capture and reduction(CCR)process emerges as an efficient catalytic strategy for CO_(2)capture and conversion to valuable chemicals.K-promoted Cu/Al_(2)O_(3)catalysts exhibited promising CO_(2)capture e...Carbon dioxide capture and reduction(CCR)process emerges as an efficient catalytic strategy for CO_(2)capture and conversion to valuable chemicals.K-promoted Cu/Al_(2)O_(3)catalysts exhibited promising CO_(2)capture efficiency and highly selective conversion to syngas(CO+H_(2)).The dynamic nature of the Cu-K system at reaction conditions complicates the identification of the catalytically active phase and surface sites.The present work aims at more precise understanding of the roles of the potassium and copper and the contribution of the metal oxide support.Whileγ-Al_(2)O_(3)guarantees high dispersion and destabilisation of the potassium phase,potassium and copper act synergistically to remove CO_(2)from diluted streams and promote fast regeneration of the active phase for CO_(2)capture releasing CO while passing H_(2).A temperature of 350℃is found necessary to activate H_(2)dissociation and generate the active sites for CO_(2)capture.The effects of synthesis parameters on the CCR activity are also described by combination of ex-situ characterisation of the materials and catalytic testing.展开更多
文摘Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.
基金supported by the National Natural Science Foundation of China(21466024)the Natural Science Foundation of Inner Mongolia(2014MS0217)
文摘The CuxO-CeO2/Fe@CNSs, CuxO-CeO2/MWCNTs-Co and CuxO-CeO2/MWCNTs-Ni catalysts were prepared by the impregnation method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, H2-temperature programmed reduction and N2 adsorption-desorption techniques. It was found that the Fe nanoparticles were encapsulated into the multi-layered carbon nanospheres （CNSs）. However, the multi-wall carbon nanotubes （MWCNTS） were generated on the Co/Al2O3 and Ni/Al2O3 precursor. The addition of carbon nanomaterial as supports could improve structural properties and low-temperature activity of the CuO-CeO2 catalyst, and save the used amount of metal catalysts in the temperature range with high selectivity for CO oxidation. The copper-cerium oxides supported on carbon nanomaterial had good resistence to H2O and CO2.
文摘A microreactor system and TPD techniques were used to study the reaction kinetics of the CO+ NO reaction and the adsorption of CO,NO,CO_2 and N_2O over Cu-Mn-O(Ⅰ)and Cu-Mn-Ce-O(Ⅱ) catalysts.The results show that the catalytic activity of(Ⅱ)is higher than that of(Ⅰ)for the CO+NO reac- tion,and the higher the conversion of NO,the larger was the activity difference between(Ⅰ)and(Ⅱ).For (Ⅰ)the rate of NO elimination is dependent on the partial pressures of NO,CO,CO_2 with the kinetics or- ders of 0.48,0.56,0.08,respectively.The TPD study shows that the presence of Ce in(Ⅱ)may promote the adsorption of NO,CO on the surface,i.e.an increase of the coverage θ_(NO),θ_(CO),which result in a decrease of the hindrance of the reaction products.For CO_2 and N_2O the situation is in the opposite,the presence of Ce makes the θ_(CO)_2)and θ_(NO)on(Ⅱ)decrease,which weakens the inhibition of CO_2 for the reaction.
基金supported by the Natural Science Foundation of Beijing Municipal(No.2252043)the National Natural Science Foundation of China(No.52170019),the Fundamental Research Funds for the Central Universities(No.06500100)the“Ten Thousand Plan”-National High-level personnel of special support program.
文摘Pt-based methanol oxidation reaction(MOR)electrocatalysts with high activity,stability,and carbon monoxide(CO)tolerance are critical for advancing direct methanol fuel cells(DMFC).Herein,a low-Pt-content electrocatalyst(Pt/CeO_(2)-carbon nanofiber(CNF))is developed through electrospinning,high-temperature calcination,and sodium borohydride(NaBH_(4))reduction,featuring highly dispersed Pt nanoparticles anchored on oxygen vacancy(Ov)-rich CeO_(2) embedded within CNF.The strong metal–support interaction(SMSI)induces Pt–O–Ce interfacial bonding,facilitating electron transfer and enhancing MOR performance.Pt/CeO_(2)-CNF achieves a mass activity of 5.29 A·mgPt^(-1),3.5 times higher than commercial Pt/C,alongside exceptional stability(92%retention after 1000 cycles)and CO tolerance.When deployed as a DMFC anode,it delivers a peak power density of 34.72 mW·cm^(-2),outperforming Pt/C by 31%.Characterization results indicate that SMSI induces charge redistribution between Pt and CeO_(2),which synergistically enhances the reaction kinetics of MOR with the hydroxyl groups produced by CeO_(2) hydrolysis.In addition,the uniform dispersion of in-situ grown CeO_(2) is ensured on CNF,and Ov acts as an anchoring point to stabilize Pt nanoparticles,improving the stability of the catalyst.This work establishes a design framework for synthesizing high-performance Pt-based DMFC electrocatalysts through controlled structural and electronic modulation strategies.
文摘A microreactor system was used to study the catalytic reaction of NO+CO→1/2 N_2+CO_2 over Cu,Fe, Mn,Cr,and Ce oxides supported on alumina,and the effect of adding Ce in supported Cu-M-O(M=Mn,Fe and Cr) catalysts on their catalytic activities for the topic reaction and the concentration of N_2O produced.It was found that the catalytic activity order of the single-element oxide is:CuO>Fe_2O_3≈Cr_2O_3> MnO_2>CeO_2>NiO.Cu-Mn-O is more active than CuO,and Cu-Fe-O is more active than Cu-Mn-O and Cu-Cr-O for NO+CO reaction.This study shows that the addition of Ce in supported Cu-M-O can promote their catalytic activities Jot the topic reaction,which makes the reaction of 2NO+CO→N_2O+CO_2 fast,and N_2O is an intermediate compound produced during NO+CO reaction.
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 Science Council of Taiwan (NSC 98-2221-E-132-003-MY3)
文摘Ammonia （NH3） has an important use in the chemical industry and is widely found in industrial wastewater. For this investigation of copper-based rare earth composite metal materials, aqueous solutions containing 400 mg/L of ammonia were oxidized in a batch-bed reac-tor with a catalyst prepared by the co-precipitation of copper nitrate, lanthanum nitrate and cerium nitrate. Barely any of the dissolved ammo-nia was removed by wet oxidation without a catalyst, but about 88% of the ammonia was reduced during wet oxidation over the catalysts at 423 K with an oxygen partial pressure of 4.0 MPa. The catalytic redox behavior was determined by cyclic voltammetry （CV）. Furthermore, the catalysts were characterized using thermogravimetric analyzer （TGA） and scanning electron microscope-energy dispersive X-ray spectroscopy （SEM-EDX）, which showed that the catalytic behavior was related to the metal oxide properties of the catalyst. In addition, the copper-lanthanum-cerium composite-induced cytotoxicity in the human lung MRC-5 cell line was tested, and the percentage cell survival was determined by 3-（4,5-dimethylthiazol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetra-zolium （MTS） analysis in vitro. No ap-parent cytotoxicity was observed when the human lung cells were exposed to the copper-lanthanum-cerium composite.
基金supported by the Science and Technology Project of China Tobacco Shaanxi Industrial Co.Ltd.(2025610000340109)the National Natural Science Foundation of China(22208373,22376217)+1 种基金Science Foundation of China University of Petroleum,Beijing(No.2462023YJRC030)State Key Laboratory of Heavy Oil Processing 1158 Open Project(SKLHOP2025115805).
文摘At present,the problem of air pollution facing the earth is becoming more and more severe,and it has become an urgent task for researchers to find effective solutions.As an important catalyst carrier and active component,CeO_(2)has received extensive attention in the field of CO-catalyzed oxidation.This article reviews the strategies of doping metal active components,regulating the loaded active sites and controlling the preferential exposure of crystal planes as approaches to enhance the low-temperature oxidation activity of CO.When the active metal is incorporated into the CeO_(2)lattice,the active metal significantly reduces the oxygen vacancy formation energy(Evf)on the catalyst surface,resulting in the high catalytic activity of the catalyst at low temperatures.When the active metal is loaded on the CeO_(2)surface,many active sites can be obtained by increasing the dispersion,and the catalytic activity can be significantly improved by introducing new interface sites between the metal and the CeO_(2)support.By precisely controlling the arrangement of surface atoms,the reactivity of Ce^(4+)/Ce^(3+)ions can be effectively regulated,thereby altering the oxygen release and absorption properties of CeO_(2).This review is helpful for the application of CeO_(2)-containing catalysts in the field of low-temperature catalytic oxidation of CO.
文摘Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found±at graphene oxide(GO)can enhance the degradation efficiency of micropollutants during ozonation.However,in this study,GO was found to promote bromate formation during ozonation of bromide-containing waters,with bromate yields from the O3/GO process more than twice those obtained using ozone alone.The promoted bromate formation was attributed to increased hydroxyl radical production,as confirmed by the significant reduction(almost 75%)in bromate yield after adding t-butanol(TBA).Cerium oxide(less tfian 5 mg/L)supported on reduced GO(xCeO2/RGO)significantly inhibited bromate formation during ozonation compared with reduced GO alone,and the optimal Ce atomic percentage(x)was determined to be 0.36%,achieving an inhibition rate of approximately 73%.Fourier transform infrared(FT-IR)spectra indicated the transformation of GO into RGO after hydrothermal treatment,and transmission electron microscope(TEM)results showed that CeO2 nanoparticles were well dispersed on the RGO surface.The X-ray photoelectron spectroscopy(XPS)spectra results demonstrated that the Ce^3+/Ce^4+ratio in xCeO2/RGO was almost 3-4 times higher than that in pure CeO2,which might be attributed to the charge transfer effect from GO to CeO2.Furthermore,Ce+on thexCeO2/RGO surface could quench Br-and BrO-to further inhibit bromate formation.Meanwhile,0.36CeO2/RGO could also enhance the degradation efficiency of N,N-diethyl-zn-toluamide(DEET)in synthetic and reclaimed water during ozonation.
文摘Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impregnation method to ensure uniform distribution of cerium and copper nitrates within the structure of coal powdery samples (according to SEM and EDX mapping). The samples reactivity was studied in an isothermal oxidation regime at 200 °C (1 h) and by DSC/TGA at 2.5 °C/min heating rate. The additives implementation was found to reduce significantly the oxidation onset temperature (△Ti = 20-55 °C), the samples oxidation delay time (△ti= 2-22 min) and overall duration of the oxidation process (△tc = 8-16 min). The additives efficiency could be graded in accordance with the activation on the coal oxidation in the following row: Cu(NO3)2 >{Cu(NO3)2 + Ce(NO3)3}> Ce(NO3)3. According to the mass spectroscopy, the obtained row of activation correlates well with the initial temperature of the studied nitrate's decomposition (from 190 to 223 °C). A presence of nitrates was found to change significantly the trend of heat release taking place during the oxidation of coal samples (according to DSC/TGA data). The influence of coal morphology and volatiles concern in initial sample on the parameters of the oxidation process was studied as well. Activation energy (Ea) of the coal oxidation was calculated using Coats-Redfern method. Maximum decrease in Ea from 69 to 58 kJ/mol was observed for the samples with Cu(NO3)2. Graphical abstract.
基金supported by National Natural Science Foundation of China(21273150)‘‘Shu Guang’’ Project of Shanghai Municipal Education CommissionShanghai Education Development Foundation(10GG23)
文摘CeO2-ZrO2 mixed oxide （Ce0.6Zr0.402） prepared by microwave-assisted heating co-precipitation was used as a support to prepare a series of CuO/Ce0.6Zr0.402 catalysts with various CuO contents （0 wt.%-1 5 wt.%） via the method of incipient-wetness im- pregnation. The obtained CuO/Ce0.6Zr0.402 samples were characterized by N2 adsorption, XRD, Raman, TEM and H2-TPR technolo- gies, and their catalytic activities for CO oxidation were investigated. The results showed that the activity of CuO/Ce0.6Zr0.402 catalyst was strongly influenced by the content of CuO, and the catalyst with 10 wt.% CuO exhibited the best catalytic activity in CO oxida- tion, which could be attributed to the high dispersion and reducibility of CuO, and high oxygen vacancy concentration in the catalyst.
基金Project supported by the National Natural Science Foundation of China(21466024)the Natural Science Foundation of Inner Mongolia(2014MS0217,2015MS0209)
文摘The CeO2/CuO catalysts using different template agent（F68 L64, F127 and P123） were synthesized by the simple template and impregnation method. They were characterized by FESEM, XRD, N2 physisorption and H2-TPR techniques. It is found that the CeO2/CuO catalysts are double pore distribution, and CeO2 can enter into the gap of CuO supports and form the contact interface of copper and cerium. Among the asprepared catalysts, the CeO2/CuO-F127 catalyst displays better activity at lower temperature and the CeO2/CuO-P123 catalyst presents higher activity at higher temperature. The CeO2/CuO-P123 catalyst has the smallest crystallite sizes of CuO and CeO2 as well as the largest size of cubes, which may improve the interaction of copper and cerium and enhance the performance of CO oxidation.
文摘Carbon dioxide capture and reduction(CCR)process emerges as an efficient catalytic strategy for CO_(2)capture and conversion to valuable chemicals.K-promoted Cu/Al_(2)O_(3)catalysts exhibited promising CO_(2)capture efficiency and highly selective conversion to syngas(CO+H_(2)).The dynamic nature of the Cu-K system at reaction conditions complicates the identification of the catalytically active phase and surface sites.The present work aims at more precise understanding of the roles of the potassium and copper and the contribution of the metal oxide support.Whileγ-Al_(2)O_(3)guarantees high dispersion and destabilisation of the potassium phase,potassium and copper act synergistically to remove CO_(2)from diluted streams and promote fast regeneration of the active phase for CO_(2)capture releasing CO while passing H_(2).A temperature of 350℃is found necessary to activate H_(2)dissociation and generate the active sites for CO_(2)capture.The effects of synthesis parameters on the CCR activity are also described by combination of ex-situ characterisation of the materials and catalytic testing.
