Photocatalytic reduction of CO2has attracted considerable interest owing to its potential to resolve the energy and environmental problems.Nevertheless,the lack of proficient photocatalysts has restricted the appli...Photocatalytic reduction of CO2has attracted considerable interest owing to its potential to resolve the energy and environmental problems.Nevertheless,the lack of proficient photocatalysts has restricted the application of solar-driven photocatalytic CO2reduction.Herein,we reported an S-scheme heterojunction by combining g-C3N4with La3+and Rh3+co-doped SrTiO3through the electrostatic self-assembly method for the efficient photocatalytic CO2reduction.In comparison with g-C3N4,the asprepared CN/LRSTO-30 wt%S-scheme heterojunction not only possesses a broadened visible-light response due to the defect states in La,Rh co-doped SrTiO3induced by codoped La3+and Rh3+but also has more adsorption sites for the capture and activation of CO2molecules.Additionally,separation and transfer efficiency of the photoinduced charge carriers is much enhanced in the CN/LRSTO-30wt%S-scheme heterojunction via its robust internal electric field,which is firmly demonstrated by in situ irradiation X-ray photoelectron spectroscopy technology.Consequently,the prepared S-scheme heterojunction achieves impressive photocatalytic CO2reduction performance with an average CO and CH4 evolution rate of4.1-1.8μmol·g-1·h-1,respectively,which are~1.9 and~22.5-fold higher than those of pure g-C3N4.This study provides innovative perspectives on the design of creative S-scheme heterojunctions for applications in photocatalytic CO2reduction.展开更多
High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicati...High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.展开更多
To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroug...To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroughly characterized. Using the XRD extrapolation method, the SnO2 lattice capacity for Cu^2+ cations is determined at 0.10 g Cu O per g of SnO2, equaling a Sn/Cu molar ratio of 84/16. Therefore, in a tetragonal rutile SnO2 lattice, only a maximum of 16% of the Sn4+ cations can be replaced by Cu^2+ to form a stable solid solution structure. If the Cu content is higher, Cu O will form on the catalyst surface, which has a negative effect on the reaction performance. For samples in a pure solid solution phase, the number of surface defects increase with increasing Cu content until it reaches the lattice capacity, as confirmed by Raman spectroscopy. As a result, the amounts of both active oxygen species and acidic sites on the surface, which critically determine the reaction performance, also increase and reach the maximum level for the catalyst with a Cu content close to the lattice capacity. A distinct lattice capacity threshold effect on the structure and reactivity of Sn-Cu binary oxide catalysts has been observed. A Sn-Cu catalyst with the best reaction performance can be obtained by doping the SnO2 matrix with the lattice capacity amount of Cu^2+.展开更多
A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I3]2-unit was proposed to be the acti...A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I3]2-unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)2I2]-is the traditional active center.A TOF of 350 h-1was obtained for the reaction over[Rh(CO)I3]2-,with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I3]2-and the cationic P(V)framework([P]+)of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.展开更多
The nanopowders of SnO2 doped with different Eu^3+ concentrations were synthesized using the modified Pechini method. The Eu^3+ concentrations were high above solubility limit. The average size of crystallites was c...The nanopowders of SnO2 doped with different Eu^3+ concentrations were synthesized using the modified Pechini method. The Eu^3+ concentrations were high above solubility limit. The average size of crystallites was controlled by the sintering temperatures. The structure and the morphology of obtained powders were examined using the XRD (X-ray diffraction) and TEM (transmission electron microscopy) analyses. The Eu2Sn2O7 phase separation was observed at relatively high concentration of Eu^3+ ions. The ZnS:Ag micropowders were mixed with the Eu^3+:SnO2 powders and their normalized emission was used to measure a relative efficiency of Eu3+:SnO〉 The photoluminescence spectra of mixed powders were measured in function of Eu^3+ concentration and average size of nanocrystallites. The reference peak method was used for comparison of intensities of the samples and selection of optimal one. The influence of the average grain size and Eu^3+ concentration on the phosphor's efficiency was discussed. The presented results confirmed the rightness of synthesis of the Eu^3+:SnO2 in form of nanocrystalites with relatively high Eu^3+ concentration.展开更多
Rhodium(Ⅲ)-catalyzed[4+1]cyclization of azobenzenes with α-Cl ketones has been developed.3-Acyl-2H-indazoles could be easily afforded in up to 97%yields for more than 30 examples.The obtained products are potentiall...Rhodium(Ⅲ)-catalyzed[4+1]cyclization of azobenzenes with α-Cl ketones has been developed.3-Acyl-2H-indazoles could be easily afforded in up to 97%yields for more than 30 examples.The obtained products are potentially valuable in organic synthesis and drug discovery.This protocol featured with high efficiency,extensive functional group tolerance and mild reaction conditions.The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.展开更多
基金financially supported by the Key-Area Research and Development Program of Guangdong Province(No.2021B0707050001)the Self-innovation Research Funding Project of Hanjiang Laboratory(No.HJL202202A001)。
摘要Photocatalytic reduction of CO2has attracted considerable interest owing to its potential to resolve the energy and environmental problems.Nevertheless,the lack of proficient photocatalysts has restricted the application of solar-driven photocatalytic CO2reduction.Herein,we reported an S-scheme heterojunction by combining g-C3N4with La3+and Rh3+co-doped SrTiO3through the electrostatic self-assembly method for the efficient photocatalytic CO2reduction.In comparison with g-C3N4,the asprepared CN/LRSTO-30 wt%S-scheme heterojunction not only possesses a broadened visible-light response due to the defect states in La,Rh co-doped SrTiO3induced by codoped La3+and Rh3+but also has more adsorption sites for the capture and activation of CO2molecules.Additionally,separation and transfer efficiency of the photoinduced charge carriers is much enhanced in the CN/LRSTO-30wt%S-scheme heterojunction via its robust internal electric field,which is firmly demonstrated by in situ irradiation X-ray photoelectron spectroscopy technology.Consequently,the prepared S-scheme heterojunction achieves impressive photocatalytic CO2reduction performance with an average CO and CH4 evolution rate of4.1-1.8μmol·g-1·h-1,respectively,which are~1.9 and~22.5-fold higher than those of pure g-C3N4.This study provides innovative perspectives on the design of creative S-scheme heterojunctions for applications in photocatalytic CO2reduction.
基金financially supported by the National Natural Science Foundation of China(Nos.51661145025,51972039,and 51803018)
摘要High-purity(99%)carbon nanocoils(CNCs)have been synthesized by using porousα-Fe2O3/SnO2 catalyst.The yield of CNCs reaches 9,098%after a 6 h growth.This value is much higher than the previously reported data,indicating that this method is promising to synthesize high-purity CNCs on a large scale.It is considered that an appropriate proportion of Fe and Sn,proper particle size distribution,and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs.Benefiting from the high-purity preparation,a CNC Buckypaper was successfully prepared and the electrical,mechanical,and electrochemical properties were investigated comprehensively.Furthermore,as one of the practical applications,the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%.This study provides a facile and economical route for preparing high-purity CNCs,which is suitable for large-quantity production.Furthermore,the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.
摘要To understand the effect of the doping amount of Cu^2+ on the structure and reactivity of SnO2 in NOx-SCR with NH3, a series of Sn-Cu-O binary oxide catalysts with different Sn/Cu ratios have been prepared and thoroughly characterized. Using the XRD extrapolation method, the SnO2 lattice capacity for Cu^2+ cations is determined at 0.10 g Cu O per g of SnO2, equaling a Sn/Cu molar ratio of 84/16. Therefore, in a tetragonal rutile SnO2 lattice, only a maximum of 16% of the Sn4+ cations can be replaced by Cu^2+ to form a stable solid solution structure. If the Cu content is higher, Cu O will form on the catalyst surface, which has a negative effect on the reaction performance. For samples in a pure solid solution phase, the number of surface defects increase with increasing Cu content until it reaches the lattice capacity, as confirmed by Raman spectroscopy. As a result, the amounts of both active oxygen species and acidic sites on the surface, which critically determine the reaction performance, also increase and reach the maximum level for the catalyst with a Cu content close to the lattice capacity. A distinct lattice capacity threshold effect on the structure and reactivity of Sn-Cu binary oxide catalysts has been observed. A Sn-Cu catalyst with the best reaction performance can be obtained by doping the SnO2 matrix with the lattice capacity amount of Cu^2+.
摘要A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I3]2-unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)2I2]-is the traditional active center.A TOF of 350 h-1was obtained for the reaction over[Rh(CO)I3]2-,with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I3]2-and the cationic P(V)framework([P]+)of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.
基金Project supported by Polish Ministry of Science and Higher Education (N507 076 32/2186, RO 02 015 02 and N507 421236)
摘要The nanopowders of SnO2 doped with different Eu^3+ concentrations were synthesized using the modified Pechini method. The Eu^3+ concentrations were high above solubility limit. The average size of crystallites was controlled by the sintering temperatures. The structure and the morphology of obtained powders were examined using the XRD (X-ray diffraction) and TEM (transmission electron microscopy) analyses. The Eu2Sn2O7 phase separation was observed at relatively high concentration of Eu^3+ ions. The ZnS:Ag micropowders were mixed with the Eu^3+:SnO2 powders and their normalized emission was used to measure a relative efficiency of Eu3+:SnO〉 The photoluminescence spectra of mixed powders were measured in function of Eu^3+ concentration and average size of nanocrystallites. The reference peak method was used for comparison of intensities of the samples and selection of optimal one. The influence of the average grain size and Eu^3+ concentration on the phosphor's efficiency was discussed. The presented results confirmed the rightness of synthesis of the Eu^3+:SnO2 in form of nanocrystalites with relatively high Eu^3+ concentration.
基金This work was supported by the National Natural Science Foundation of China(No.21572072)111 Project(No.BC 2018061)Xiamen Southern Oceanographic Center(No.15PYY052SF01).
摘要Rhodium(Ⅲ)-catalyzed[4+1]cyclization of azobenzenes with α-Cl ketones has been developed.3-Acyl-2H-indazoles could be easily afforded in up to 97%yields for more than 30 examples.The obtained products are potentially valuable in organic synthesis and drug discovery.This protocol featured with high efficiency,extensive functional group tolerance and mild reaction conditions.The one-step efficient construction of an anti-inflammatory agent confirms the practicability of this procedure.