A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃...A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃and exhibited an excellent H_(2)O or/and SO_(2) resistance at 275℃.To understand the promotional mechanism of Cu modification,the correlation among the"activity-structure-property"were tried to establish systematically.Cu species highly dispersed on NbCe catalyst to serve as the active component.The strong interaction among Cu,Nb and Ce promoted the emergence of NbO4 and induced more Bronsted acid sites.And Cu modification obviously enhanced the redox behavior of the NbCe catalyst.Besides,EPR probed the Cu species exited in the form of monomeric and dimeric Cu^(2+),the isolated Cu^(2+)acted as catalytic active sites to promote the reaction:Cu^(2+)-NO_(3)^(-)+NO(g)→Cu^(2+)-NO_(2)^(-)+NO_(2)(g).Then the generated NO_(2) would accelerate the fast-SCR reaction process and thus facilitated the lowtemperature deNO_(x) efficiency.Moreover,surface nitrates became unstable and easy to decompose after Cu modification,thus providing additional adsorption and activation sites for NH3,and ensuring the improvement of catalytic activity at high temperature.Since the NH3-SCR reaction followed by E-R reaction pathway efficaciously over Cu_(0.010)/Nb_(1)Ce_(3) catalyst,the excellent H_(2)O and SO_(2) resistance was as expected.展开更多
Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and al...Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.展开更多
Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low t...Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H_2 temperature-programmed reduction（TPR） and NH_3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu^（2＋） species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO_2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH_3 by O_2 and decreased surface acidity of the catalyst.展开更多
Fe-ZSM-5 catalysts modified by Cu and Ce by aqueous solution ion-exchange and incipient wetness impregnation methods were tested in the selective catalytic reduction of NO_(x) with NH_(3).A variety of characterization...Fe-ZSM-5 catalysts modified by Cu and Ce by aqueous solution ion-exchange and incipient wetness impregnation methods were tested in the selective catalytic reduction of NO_(x) with NH_(3).A variety of characterization techniques(NH_(3)-SCO,BET,XRD,XPS,UV-Vis,NH_(3)-TPD,H_(2)-TPR)were used to explore the changes of the active sites,acid sites and pore structure of the catalyst.It was found that the dispersion of active Cu species and Fe species had great influences on the catalytic activity in the whole catalytic process.The Cu doping into the Fe-ZSM-5 catalyst produced new active species,isolated Cu ions and CuO particles,resulting in the improved low-temperature catalytic activity.However,the NH_(3) oxidation was enhanced,and part of the Fe^(3+)active sites and more Brønsted acidic sites in the catalyst were occupied by Cu species,which causes the decrease of the high-temperature activity.The recovery of hightemperature activity could be attributed to the recovery of active Cu species and Fe species promoted by Ce and the promotion of active species dispersion.The results provide theoretical support for adjusting the active window of Febased SCR catalyst by multi-metal doping.展开更多
The present article reports a novel self‐standing nanostructured Au‐Cu(I)@Na2Ti6O13plasmonic photocatalytic membrane,which is prepared by a hydrothermal reaction followed by a simple subsequent heat treatment proces...The present article reports a novel self‐standing nanostructured Au‐Cu(I)@Na2Ti6O13plasmonic photocatalytic membrane,which is prepared by a hydrothermal reaction followed by a simple subsequent heat treatment process.The morphological structure,elemental composition,crystalline phases,and optical properties of the membrane were studied in detail by field‐emission scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron spectroscopy,X‐ray diffraction,and ultraviolet‐visible spectroscopy.Compared with that of a pure Na2Ti6O13membrane,the Au‐Cu(I)@Na2Ti6O13membrane displayed much higher photocatalytic activity for the decomposition of acetaldehyde,a typical volatile organic compound,under visible light illumination.It was found that the photocatalytic activity of the Au‐Cu(I)@Na2Ti6O13membrane increased as the amount of Au was increased.The membrane loaded with2.85wt%Au showed the highest photocatalytic activity in the decomposition of acetaldehyde of the investigated materials.We found that in the photocatalyst membrane,Na2Ti6O13acted as a support material,Au displayed plasmonic absorption,and Cu(I)behaved as a co‐catalyst.The present membrane materials can avoid the self‐aggregation typically observed during the course of photocatalytic reactions.As a result,they can be easily separated,recycled,and reactivated after their practical application,making these functional materials attractive for use in air cleaning applications.展开更多
基金Financial support from the National Natural Science Foundation of China,China(Nos.21972062,21976081,21976111)。
文摘A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃and exhibited an excellent H_(2)O or/and SO_(2) resistance at 275℃.To understand the promotional mechanism of Cu modification,the correlation among the"activity-structure-property"were tried to establish systematically.Cu species highly dispersed on NbCe catalyst to serve as the active component.The strong interaction among Cu,Nb and Ce promoted the emergence of NbO4 and induced more Bronsted acid sites.And Cu modification obviously enhanced the redox behavior of the NbCe catalyst.Besides,EPR probed the Cu species exited in the form of monomeric and dimeric Cu^(2+),the isolated Cu^(2+)acted as catalytic active sites to promote the reaction:Cu^(2+)-NO_(3)^(-)+NO(g)→Cu^(2+)-NO_(2)^(-)+NO_(2)(g).Then the generated NO_(2) would accelerate the fast-SCR reaction process and thus facilitated the lowtemperature deNO_(x) efficiency.Moreover,surface nitrates became unstable and easy to decompose after Cu modification,thus providing additional adsorption and activation sites for NH3,and ensuring the improvement of catalytic activity at high temperature.Since the NH3-SCR reaction followed by E-R reaction pathway efficaciously over Cu_(0.010)/Nb_(1)Ce_(3) catalyst,the excellent H_(2)O and SO_(2) resistance was as expected.
基金supported by the National Natural Science Foundation of China(22102132)the Funds for Basic Scientific Research in Central Universities+2 种基金the Scientific Research Foundation of Qingdao UniversityTaishan Scholar Program(NO.tsqnz20231213)sponsored by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2024101)。
文摘Platinum group alloys have an excellent electronic structure for oxidation of alcohols,but the active sites are more susceptible to deactivation by CO adsorbates(CO_(ads)).The precise integration of single-atom and alloy structures is highly attractive for energy conversion but still a challenge.Here,we report an ionexchange coupled in situ reduction strategy to fabricate hollow PtPdTe alloy nanoreactors loaded with atomically dispersed Cu sites(Cu_(SA)/h-PtPdTe NRs).The planted oxyphilic Cu single sites and resulted compressive strains are conductive to modulating the electronic structure of the active sites,which changes the rate-determining step of the reaction while inhibiting the formation of CO_(ads)and modulating the adsorption of intermediates,resulting in the improved activity and stability.Specifically,the obtained Cu_(SA)/h-PtPdTe NRs exhibit an excellent oxidation performance of multiple alcohols,especially for methanol and ethanol,with 8.0 and 10.3 times of the mass activity higher than Pt/C,and the activity could be recovered by refreshing the electrolyte and could be sustained for 72,000 and 36,000 s,respectively.Meanwhile,Cu_(SA)/h-PtPdTe NRs show superior oxidation performance and durability to ethylene glycol and glycerol.This work pioneers the realization of precise modulation of catalytic sites using single atoms and provides an encouraging pathway for the design of efficient and stable electrocatalysts for the oxidation of multiple alcohols,which could broaden the range of options and sources of fuel cells.
基金Project supported by the the National Natural Science Foundation of China(51372137)Ministry of Science and Technology,China(2015AA034603)
文摘Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H_2 temperature-programmed reduction（TPR） and NH_3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu^（2＋） species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO_2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH_3 by O_2 and decreased surface acidity of the catalyst.
基金Project(51906089)supported by the National Natural Science Foundation of ChinaProject(NELMS2018A18)supported by the National Engineering Laboratory for Mobile Source Emission Control Technology,China+1 种基金Project(XNYQ2021-002)supported by the Provincial Engineering Research Center for New Energy Vehicle Intelligent Control and Simulation Test Technology of Sichuan,ChinaProject(GY2020016)supported by the Zhenjiang City Key R&D Program,China。
文摘Fe-ZSM-5 catalysts modified by Cu and Ce by aqueous solution ion-exchange and incipient wetness impregnation methods were tested in the selective catalytic reduction of NO_(x) with NH_(3).A variety of characterization techniques(NH_(3)-SCO,BET,XRD,XPS,UV-Vis,NH_(3)-TPD,H_(2)-TPR)were used to explore the changes of the active sites,acid sites and pore structure of the catalyst.It was found that the dispersion of active Cu species and Fe species had great influences on the catalytic activity in the whole catalytic process.The Cu doping into the Fe-ZSM-5 catalyst produced new active species,isolated Cu ions and CuO particles,resulting in the improved low-temperature catalytic activity.However,the NH_(3) oxidation was enhanced,and part of the Fe^(3+)active sites and more Brønsted acidic sites in the catalyst were occupied by Cu species,which causes the decrease of the high-temperature activity.The recovery of hightemperature activity could be attributed to the recovery of active Cu species and Fe species promoted by Ce and the promotion of active species dispersion.The results provide theoretical support for adjusting the active window of Febased SCR catalyst by multi-metal doping.
基金supported by the National Natural Science Foundation of China(51772230,51461135004)Hubei Foreign Science and Technology Cooperation Project(2017AHB059)the Japan Society for the Promotion of Science(JSPS)for an Invitation Fellowship for Foreign Researchers(L16531)~~
文摘The present article reports a novel self‐standing nanostructured Au‐Cu(I)@Na2Ti6O13plasmonic photocatalytic membrane,which is prepared by a hydrothermal reaction followed by a simple subsequent heat treatment process.The morphological structure,elemental composition,crystalline phases,and optical properties of the membrane were studied in detail by field‐emission scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron spectroscopy,X‐ray diffraction,and ultraviolet‐visible spectroscopy.Compared with that of a pure Na2Ti6O13membrane,the Au‐Cu(I)@Na2Ti6O13membrane displayed much higher photocatalytic activity for the decomposition of acetaldehyde,a typical volatile organic compound,under visible light illumination.It was found that the photocatalytic activity of the Au‐Cu(I)@Na2Ti6O13membrane increased as the amount of Au was increased.The membrane loaded with2.85wt%Au showed the highest photocatalytic activity in the decomposition of acetaldehyde of the investigated materials.We found that in the photocatalyst membrane,Na2Ti6O13acted as a support material,Au displayed plasmonic absorption,and Cu(I)behaved as a co‐catalyst.The present membrane materials can avoid the self‐aggregation typically observed during the course of photocatalytic reactions.As a result,they can be easily separated,recycled,and reactivated after their practical application,making these functional materials attractive for use in air cleaning applications.
