Ultra-long n-alkanes are highly valuable in both scientific research and as major constituents of specialty high-melting-point waxes.Unlike conventional methods(e.g.,Fischer–Tropsch(FT),ethylene oligomerization,and p...Ultra-long n-alkanes are highly valuable in both scientific research and as major constituents of specialty high-melting-point waxes.Unlike conventional methods(e.g.,Fischer–Tropsch(FT),ethylene oligomerization,and polyethylene cracking)typically resulting in wide n-alkane distributions,the elaborate design strategy presented herein allows the direct synthesis of pure,long n-alkanes using a modular splicing method with acetone,furfural,and fatty acid anhydrides or acyl chlorides as bio-blocks.The herein approach is based on a simple four-step catalytic reaction scheme involving C–C chain elongation and C–O bond activation.The synthesized pure n-alkanes had a carbon chain length as high as C_(49)(total yield of 49%).The synthesis approach also allows to selectively prepare n-alkanes with even and odd carbon numbers ranging from C15 to C_(49).This process represents a great breakthrough in the synthesis of long-chain pure n-alkanes,surpassing the carbon number limitations reported in previous methodologies.展开更多
Silver-copper electrocatalysts have demonstrated effectively catalytic performance in electroreduction CO_(2) toward CH_(4),yet a revealing insight into the reaction pathway and mechanism has remained elusive.Herein,w...Silver-copper electrocatalysts have demonstrated effectively catalytic performance in electroreduction CO_(2) toward CH_(4),yet a revealing insight into the reaction pathway and mechanism has remained elusive.Herein,we construct chemically bonded Ag-Cu_(2)O boundaries,in which the complete reduction of Cu_(2)O to Cu has been strongly impeded owing to the presence of surface Ag shell.The interfacial confinement effect helps to maintain Cu^(+)sites at the Ag-Cu_(2)O boundaries.Using in situ/operando spectroscopy and theoretical simulations,it is revealed that CO_(2) is enriched at the Ag-Cu_(2)O boundaries due to the enhanced physisorption and chemisorption to CO_(2),activating CO_(2) to form the stable intermediate^(*)CO.The boundaries between Ag shell and the Cu_(2)O mediate local^(*)CO coverage and promote^(*)CHO intermediate formation,consequently facilitating CO_(2)-to-CH_(4) conversion.This work not only reveals the structure-activity relationships but also offers insights into the reaction mechanism on Ag-Cu catalysts for efficient electrocatalytic CO_(2) reduction.展开更多
This work describes the use of TiO_(2)nanotubes-based electrodes(TNT)modified with Cu_(2)O nanostructures and gold nanoparticles for the photoelectroreduction of CO_(2)to produce value-added compounds.A thin layer of ...This work describes the use of TiO_(2)nanotubes-based electrodes(TNT)modified with Cu_(2)O nanostructures and gold nanoparticles for the photoelectroreduction of CO_(2)to produce value-added compounds.A thin layer of polydopamine was used as both an adherent agent and an electron transfer mediator,due to itsπ-conjugated electron system.The highest production yield was achieved using a TNT@PDA/Nc/Au40%electrode,with Faradaic efficiencies of 47.4%(110.5μM cm^(-2))and 27.8%(50.4μM cm^(-2))for methanol and methane,respectively.The performance of the photoelectrodes was shown to be Cu_(2)O facet-dependent,with cubic structures leading to greater conversion of CO_(2)to methanol(43%)and methane(27%),compared to the octahedral morphology,while a higher percentage of metallic gold on the nanostructured Cu_(2)O surface was mainly important for CH4production.Density functional theory(DFT)calculations supported these findings,attributing the superior photoelectrocatalytic performance of the TNT@PDA/Nc/Au40%electrode for CH4generation to the formation of an OCH3intermediate bonded to Au atoms.Studies using isotope-labeling and analysis by gas chromatograph-mass(GC-MS)demonstrated that13CO_(2)was the source for photoelectrocatalytic generation of13CH3OH and13CH313CH2OH.展开更多
An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant s...An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ-species participated in efficient chemisorption and activation of CO_(2)to generate monodentate carbonate.Simultaneously,plentiful available Ni0sites facilitated H2dissociation,thus CO_(2)and H2were smoothly activated at zones of Coδ-species and Ni0,respectively.Detailed in situ DRIFTS,quasi situ XPS,TPSR,and DFT calculations substantiated a new formate evolution mechanism via monodentate carbonate instead of traditional bidentate carbonate based on synergistic catalysis of Coδ-species and Ni0.The zonal activation of CO_(2)and H2by tuning electron behaviors of double-center catalysts can boost heterogeneous catalytic hydrogenation performance.展开更多
The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is res...The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is responsible for the adsorption and activation of CO_(2)and the generation of CO and H2via side reactions often lead to poor efficiency and low selectivity of the catalyst.Herein,Cu,Pd,and PdCu metal clusters cocatalyst-anchored defective TiO_(2)nanotubes(Cu/TiO_(2)-SBO,Pd/TiO_(2)-SBO,and Pd1Cu1/TiO_(2)-SBO)were designed via a simple solution impregnation reduction and applied for photocatalytic conversion of CO_(2)to CH_(4).The Pd1Cu1/TiO_(2)-SBO photocatalyst exhibits excellent catalytic performance among the other catalysts for photoreduction of CO_(2)into CH_(4).More interestingly,the product selectivity of CH_(4)reaches up to 100%with a rate of 25μmol g^(-1)h^(-1).In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)simulations indicate that the main reasons for the high selectivity of CH_(4)are attributed to the PdCu alloy and oxygen vacancies,which jointly enhance the photoinduced carrier separation and lower energy barriers of key intermediates.Moreover,due to the tunable d-band center of the Cu site in the PdCu alloy,the generated intermediates can be well prevented from poisoning and promoted to participate in further reactions.Hopefully,the current study will provide insight into the development of new,highly selective photocatalysts for the visible light-catalytic reduction of CO_(2)into CH_(4).展开更多
目的针对国内处理原料气在气质较富时乙烷回收装置单一、产物回收率低的问题,在原有工艺冷干气回流流程(cold residue reflux process,CRR)的基础上提出两种高效乙烷回收流程,即带闪蒸的冷干气回流流程(cold residue reflux process wit...目的针对国内处理原料气在气质较富时乙烷回收装置单一、产物回收率低的问题,在原有工艺冷干气回流流程(cold residue reflux process,CRR)的基础上提出两种高效乙烷回收流程,即带闪蒸的冷干气回流流程(cold residue reflux process with flash evaporator,CRR-FE)和部分原料气过冷分离的冷干气回流流程(cold residue reflux process with feed subcooled,CRR-PS)。方法在保证乙烷回收率高于95%的条件下,利用HYSYS软件模拟改进工艺流程,设置了3组逐渐变富的气质对CRR及改进流程进行了综合能耗和火用分析对比。结果改进后的流程有很好的节能效果,其中CRR-PS流程节能效果明显,在GPM值为4.3时,CRR-PS流程综合能耗节约了9.4%。3种流程火用损最大为主体设备压缩机中的外输压缩机,其次是塔设备中脱甲烷塔和丙烷制冷,最后是换热器、空冷器及水冷器;改进后的流程性能很好,整体火用效率在80%以上,总火用效率排序为CRR-PS>CRR-FE>CRR;当GPM值为4.3时,CRR-PS火用损为28471 kW,相比于CRR降低了3.9%,表明CRR-PS火用损失较少,有很好的节能潜力。结论CRR-PS流程对富气适应性更强,节能效果更好。展开更多
Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile...Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.展开更多
基金supported by National Natural Science Foundation of China(General Program,No.22372060)Shanghai Municipal Science and Technology Commission Project(No.22dz1209300)National Natural Science Youth Fund(No.22205065)。
文摘Ultra-long n-alkanes are highly valuable in both scientific research and as major constituents of specialty high-melting-point waxes.Unlike conventional methods(e.g.,Fischer–Tropsch(FT),ethylene oligomerization,and polyethylene cracking)typically resulting in wide n-alkane distributions,the elaborate design strategy presented herein allows the direct synthesis of pure,long n-alkanes using a modular splicing method with acetone,furfural,and fatty acid anhydrides or acyl chlorides as bio-blocks.The herein approach is based on a simple four-step catalytic reaction scheme involving C–C chain elongation and C–O bond activation.The synthesized pure n-alkanes had a carbon chain length as high as C_(49)(total yield of 49%).The synthesis approach also allows to selectively prepare n-alkanes with even and odd carbon numbers ranging from C15 to C_(49).This process represents a great breakthrough in the synthesis of long-chain pure n-alkanes,surpassing the carbon number limitations reported in previous methodologies.
基金financially supported by the National Natural Science Foundation of China (21968020)the Natural Science Foundation of Inner Mongolia (2022MS02011 and 2023MS02014)+1 种基金the Science and Technology Projects of China Northern Rare Earth (BFXT-2022-D-0023)the Open Research Subject of Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control (2021Z01)。
文摘Silver-copper electrocatalysts have demonstrated effectively catalytic performance in electroreduction CO_(2) toward CH_(4),yet a revealing insight into the reaction pathway and mechanism has remained elusive.Herein,we construct chemically bonded Ag-Cu_(2)O boundaries,in which the complete reduction of Cu_(2)O to Cu has been strongly impeded owing to the presence of surface Ag shell.The interfacial confinement effect helps to maintain Cu^(+)sites at the Ag-Cu_(2)O boundaries.Using in situ/operando spectroscopy and theoretical simulations,it is revealed that CO_(2) is enriched at the Ag-Cu_(2)O boundaries due to the enhanced physisorption and chemisorption to CO_(2),activating CO_(2) to form the stable intermediate^(*)CO.The boundaries between Ag shell and the Cu_(2)O mediate local^(*)CO coverage and promote^(*)CHO intermediate formation,consequently facilitating CO_(2)-to-CH_(4) conversion.This work not only reveals the structure-activity relationships but also offers insights into the reaction mechanism on Ag-Cu catalysts for efficient electrocatalytic CO_(2) reduction.
基金FAPESP,Brazil(#2023/10027-5,#2014/50945-4,#2020/15230-5,and#2021/000675-4)CNPq,Brazil(#465571/2014-0,#303269/2021-9,and#307837/2014-9)+6 种基金Instituto Serrapilheira(grant number Serra-2211-41925)FAPEMIG,Brazil(#PPM-00831-15)for support of this workCNPq,Brazil(#105944/2022-0)and PROPEUNESP(13/2022)FAPESP(#2019/00463-7,#2018/22845-6,and#2021/08007-0,respectively)for scholarshipsthe National Institute for Alternative Technologies of Detection,Toxicological Evaluation and Removal of Micropollutants and Radioactives(INCT-DATREM)the support of the Research Centre for Greenhouse Gas Innovation(RCGI),hosted by the University of Sao Paulo(USP)and sponsored by FAPESP and Shell Brasilthe strategic support given by ANP,Brazil(Brazilian National Oil,Natural Gas,and Biofuels Agency)through the R&D levy regulation。
文摘This work describes the use of TiO_(2)nanotubes-based electrodes(TNT)modified with Cu_(2)O nanostructures and gold nanoparticles for the photoelectroreduction of CO_(2)to produce value-added compounds.A thin layer of polydopamine was used as both an adherent agent and an electron transfer mediator,due to itsπ-conjugated electron system.The highest production yield was achieved using a TNT@PDA/Nc/Au40%electrode,with Faradaic efficiencies of 47.4%(110.5μM cm^(-2))and 27.8%(50.4μM cm^(-2))for methanol and methane,respectively.The performance of the photoelectrodes was shown to be Cu_(2)O facet-dependent,with cubic structures leading to greater conversion of CO_(2)to methanol(43%)and methane(27%),compared to the octahedral morphology,while a higher percentage of metallic gold on the nanostructured Cu_(2)O surface was mainly important for CH4production.Density functional theory(DFT)calculations supported these findings,attributing the superior photoelectrocatalytic performance of the TNT@PDA/Nc/Au40%electrode for CH4generation to the formation of an OCH3intermediate bonded to Au atoms.Studies using isotope-labeling and analysis by gas chromatograph-mass(GC-MS)demonstrated that13CO_(2)was the source for photoelectrocatalytic generation of13CH3OH and13CH313CH2OH.
基金funded by the Science and Technology Project of Southwest United Graduate School of Yunnan Province(No.202302AQ370002)the National Natural Science Foundation of China(No.22206066)。
文摘An in-depth mechanism in zonal activation of CO_(2)and H2molecular over dual-active sites has not been revealed yet.Here,Ni-Co-MgO was rationally constructed to elucidate the CO_(2)methanation mechanism.The abundant surface nickel and cobalt components as active sites led to strong Ni-Co interaction with charge transfer from nickel to cobalt.Notably,electron-enriched Coδ-species participated in efficient chemisorption and activation of CO_(2)to generate monodentate carbonate.Simultaneously,plentiful available Ni0sites facilitated H2dissociation,thus CO_(2)and H2were smoothly activated at zones of Coδ-species and Ni0,respectively.Detailed in situ DRIFTS,quasi situ XPS,TPSR,and DFT calculations substantiated a new formate evolution mechanism via monodentate carbonate instead of traditional bidentate carbonate based on synergistic catalysis of Coδ-species and Ni0.The zonal activation of CO_(2)and H2by tuning electron behaviors of double-center catalysts can boost heterogeneous catalytic hydrogenation performance.
基金the financial support from the Program for Innovative Research Team in University of Henan Province(21IRTSTHN009)Science and Technology Fund of Henan Province(225200810051)Natural Science Foundation of Henan Province(222300420406)。
文摘The photoreduction of CO_(2)into CH_(4)with simultaneous high activity and selectivity is a promising strategy to increase energy supply and alleviate global warming.However,the absence of the active sites that is responsible for the adsorption and activation of CO_(2)and the generation of CO and H2via side reactions often lead to poor efficiency and low selectivity of the catalyst.Herein,Cu,Pd,and PdCu metal clusters cocatalyst-anchored defective TiO_(2)nanotubes(Cu/TiO_(2)-SBO,Pd/TiO_(2)-SBO,and Pd1Cu1/TiO_(2)-SBO)were designed via a simple solution impregnation reduction and applied for photocatalytic conversion of CO_(2)to CH_(4).The Pd1Cu1/TiO_(2)-SBO photocatalyst exhibits excellent catalytic performance among the other catalysts for photoreduction of CO_(2)into CH_(4).More interestingly,the product selectivity of CH_(4)reaches up to 100%with a rate of 25μmol g^(-1)h^(-1).In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)simulations indicate that the main reasons for the high selectivity of CH_(4)are attributed to the PdCu alloy and oxygen vacancies,which jointly enhance the photoinduced carrier separation and lower energy barriers of key intermediates.Moreover,due to the tunable d-band center of the Cu site in the PdCu alloy,the generated intermediates can be well prevented from poisoning and promoted to participate in further reactions.Hopefully,the current study will provide insight into the development of new,highly selective photocatalysts for the visible light-catalytic reduction of CO_(2)into CH_(4).
文摘目的针对国内处理原料气在气质较富时乙烷回收装置单一、产物回收率低的问题,在原有工艺冷干气回流流程(cold residue reflux process,CRR)的基础上提出两种高效乙烷回收流程,即带闪蒸的冷干气回流流程(cold residue reflux process with flash evaporator,CRR-FE)和部分原料气过冷分离的冷干气回流流程(cold residue reflux process with feed subcooled,CRR-PS)。方法在保证乙烷回收率高于95%的条件下,利用HYSYS软件模拟改进工艺流程,设置了3组逐渐变富的气质对CRR及改进流程进行了综合能耗和火用分析对比。结果改进后的流程有很好的节能效果,其中CRR-PS流程节能效果明显,在GPM值为4.3时,CRR-PS流程综合能耗节约了9.4%。3种流程火用损最大为主体设备压缩机中的外输压缩机,其次是塔设备中脱甲烷塔和丙烷制冷,最后是换热器、空冷器及水冷器;改进后的流程性能很好,整体火用效率在80%以上,总火用效率排序为CRR-PS>CRR-FE>CRR;当GPM值为4.3时,CRR-PS火用损为28471 kW,相比于CRR降低了3.9%,表明CRR-PS火用损失较少,有很好的节能潜力。结论CRR-PS流程对富气适应性更强,节能效果更好。
基金financially supported by the National Natural Science Foundation of China(No.22072069)the Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials(Wuhan University of Science and Technology No.WKDM202303).
文摘Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.
