Visible light photocatalytic CO2 conversion is a promising solution to global warming and energy shortage.Herein,we build a well-designed bridge-like nanostructure,that is,the phosphonated Ru complex(RuP)light absorbe...Visible light photocatalytic CO2 conversion is a promising solution to global warming and energy shortage.Herein,we build a well-designed bridge-like nanostructure,that is,the phosphonated Ru complex(RuP)light absorber–TiO2 bridge–Cu catalyst.In this nanostructure,brookite TiO2 serving as a bridge is spatially connected to the RuP and Cu on each of its sides and could thus physically separate the photoexcited holes and electrons over the RuP and Cu,respectively.Given its eff ective charge separation,this RuP–TiO2–Cu assembly exhibits superior CO2 photoreduction activity relative to RuP–SiO2–Cu under visible light irradiation(λ>420 nm).The catalytic activity is further optimized by adopting brookite TiO2 with various electronic band structures.Results reveal the rapid movement of electrons from the RuP through the conduction band of TiO2 and fi nally to the Cu surface.This property is crucial in CO2 photoreduction activity.展开更多
Reduction of CO2to solar fuels by artificial photosynthesis technology has attracted considerable attention. However, insufficient separation of charge carriers and weak CO2adsorption hamper the photocatalytic CO2 red...Reduction of CO2to solar fuels by artificial photosynthesis technology has attracted considerable attention. However, insufficient separation of charge carriers and weak CO2adsorption hamper the photocatalytic CO2 reduction activity. Herein, we tackle these challenges by introducing oxygen vacancies (OVs) on the two-dimensional Bi4Ti3O12ultrathin nanosheets via a combined hydrothermal and postreduction process. Selective photodeposition experiment of Pt over Bi4Ti3O12discloses that the ultrathin structure shortens the migration distance of photo-induced electrons from bulk to the surface, benefiting the fast participation in the CO2reduction reaction. The introduction of OVs on ultrathin Bi4Ti3O12 nanosheets leads to enormous amelioration on surface state and electronic structure, thereby resulting in enhanced CO2adsorption, photoabsorption and charge separation efficiency. The photocatalytic experiments uncover that ultrathin Bi4Ti3O12nanosheets with OVs reveal a largely enhanced CO2photoreduction activity for producing CO with a rate of 11.7 lmol g-1h-1in the gas–solid system, 3.2 times higher than that of bulk Bi4Ti3O12. This work not only yields efficient ultrathin photocatalysts with OVs, but also furthers our understanding on enhancing CO2reduction via cooperative tactics.展开更多
COphotoreduction is an attractive process which allows the storage of solar energy and synthesis of solar fuels. Many different photocatalytic systems have been developed, while the alternative photo-reactors are stil...COphotoreduction is an attractive process which allows the storage of solar energy and synthesis of solar fuels. Many different photocatalytic systems have been developed, while the alternative photo-reactors are still insufficiently investigated. In this work, photoreduction of COwith HO into CHwas investigated in a modified concentrating solar reactor, using TiOand Pt/TiOas the catalysts. The TiOand Pt/TiOsamples were extensively characterized by different techniques including powder X-ray diffraction（XRD）, Nadsorption/desorption and UV–vis absorption. The catalytic performance of the TiOand Pt/TiOsamples in the gas phase was evaluated under unconcentrated and concentrated Xe-lamp light and nature solar light with different concentrating ratios. Various parameters of the reaction system and the catalysts were investigated and optimized to maximize the catalytic performance of COreduction system. Compared with the normal light irradiation, the TiOand Pt/TiOsamples show higher photocatalytic activity（about 6–7 times） for reducing COinto CHunder concentrated Xe-lamp light and nature solar light. In the range of experimental light intensity, it is found that the concentration of the light makes it suitable for the catalytic reaction, and increases the utilization efficiency of the TiOand Pt/TiOsamples while does not decrease the quantum efficiency.展开更多
Photocatalytic reduction of CO2 into value-added products is a promising strategy for mitigating environmental and energy problems simultaneously.Herein,we developed Au sheets with subtle grain boundaries on ultrathin...Photocatalytic reduction of CO2 into value-added products is a promising strategy for mitigating environmental and energy problems simultaneously.Herein,we developed Au sheets with subtle grain boundaries on ultrathin Ni(OH)2 nanosheets as efficient photocatalysts for CO2 reduction.According to mechanistic studies,grain boundaries on the Au sheets served as electron trapping sites which enabled the optimization of electron-hole separation.Moreover,grain boundaries perturbed electron distribution,which assisted in stabilizing CO2^δ- and HCOO^* intermediates.As a result,the unique hybrid structure achieved a high rate of 75.2μmol g^-1h^-1 for CO2 photoreduction.This work demonstrates the importance of defect engineering in designing active photocatalysts and also provides insight into development of related photo-energy conversion schemes.展开更多
The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photo...The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.展开更多
Visible-light-driven CO2 photoreduction to achieve renewable materials,such as syngas,hydrocarbons,and alcohols,is a key process that could relieve environmental problems and the energy crisis simultaneously.Reduction...Visible-light-driven CO2 photoreduction to achieve renewable materials,such as syngas,hydrocarbons,and alcohols,is a key process that could relieve environmental problems and the energy crisis simultaneously.Reduction of syngas products with diff erent H2:CO proportions is highly expected to produce high value-added chemicals in the industry.However,the development of technologies employing long-wavelength irradiation to achieve CO2 photoreduction and simultaneous tuning of the resultant H2:CO proportion remains a challenging endeavor.In this work,we carried out interfacial engineering by designing a series of heterostructured layered double-hydroxide/MoS2 nanocomposites via electrostatic self-assembly.The syngas proportion(H 2:CO)obtained from CO2 photoreduction could be modulated from 1:1 to 9:1 by visible-light irradiation(λ>400 nm)under the control of the interface-rich heterostructures.This work provides a cost-eff ective strategy for solar-tofuel conversion in an artificial photosynthetic system and describes a novel route to produce syngas with targeted proportions.展开更多
Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the C...Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the CO_(2) reduction catalyst[ReI(bpy)(CO)_(3)Cl]and the porphyrin photosensitizer as the monomeric building units.The light‐harvesting properties of the porphyrin itself,augmented by the extendedπ‐conjugated planar structure of 2D COF,enable H_(2)PReBpy‐COF the excellent light‐harvesting capability,efficient charge separation,and fast interfacial charge transfer.In addition,a large amount of uniformly distributed[ReI(bpy)(CO)_(3)Cl]units offer H_(2)PReBpy‐COF an excellent activity toward photocatalytic CO_(2) reduction with moderate selectivity and reusability.This study demonstrated a proof of concept in which the advantages of COFs and functional monomers are rationally integrated for photocatalytic solar fuel conversion.展开更多
The performance of CeO2-TiO2 photocatalyst for the photocatalytic reduction of CO2 into methanol was studied under visible light irradiation. The as-prepared catalysts were characterized for their structural, textural...The performance of CeO2-TiO2 photocatalyst for the photocatalytic reduction of CO2 into methanol was studied under visible light irradiation. The as-prepared catalysts were characterized for their structural, textural and optical properties using X-ray diffraction（XRD）, field emission scanning electron microscopy（FESEM）, X-ray photoelectron spectroscopy（XPS）, nitrogen physisorption analysis, UV-vis spectroscopy and photoluminescence（PL） spectroscopy. The characterization results indicated that the presence of CeO2 stabilized the anatase phase of TiO2, decreased its crystallite size, increased the surface area, reduced the band gap energy and lowered the rate of electron-hole pair recombination. The CeO2-TiO2 photocatalyst showed an increased methanol yield of 18.6 μmol/g under visible light irradiation, compared to the bare TiO2（6.0 μmol/g）.展开更多
A series of Au/g-C3N4(Au/CN)nanocomposites were successfully prepared,where g-C3N4 nanosheets(CN NSs)served as a substrate for the growth of different sized Au nanoparticles(Au NPs)using the constant temperature bath-...A series of Au/g-C3N4(Au/CN)nanocomposites were successfully prepared,where g-C3N4 nanosheets(CN NSs)served as a substrate for the growth of different sized Au nanoparticles(Au NPs)using the constant temperature bath-reduction method.The effect of Au NP size on electron transfer efficiency between the interfaces of the nanocomposite was studied.The three-dimensional finite-difference time-domain results revealed that larger Au NPs showed increased strength of the localized surface plasmon resonance effect.An increased number of high-energy electrons were available for transfer from Au NPs to CN under the visible light irradiation,inhibiting electron transfer from CN to Au NPs.Photoelectrochemical performance analysis showed that smaller Au NPs exhibited higher separation efficiency of the electron-hole pairs photo-generated with reasonable distribution density.These results are favorable for the improvement of photocatalytic performance.Compared to other nanocomposites,the 3-Au/CN sample(prepared using 3 mL HAuCl4 solution)with reasonable distribution density and small Au NPs exhibited the best photodegradation activity(92.66%)of RhB in 30 min under the visible light irradiation and photoreduction performance of CO2 to CO and CH4 with yields of 77.5 and 38.5μmol/g,respectively,in 8 h under UV light irradiation.Considering the experimental results in the context of the literature,a corresponding size-dependent photocatalytic mechanism was proposed.展开更多
Converting solar energy into hydrogen and hydrocarbon fuels through photocatalytic H2production and CO2photoreduction is a highly promising approach to address growing demand for clean andrenewable energy resources.Ho...Converting solar energy into hydrogen and hydrocarbon fuels through photocatalytic H2production and CO2photoreduction is a highly promising approach to address growing demand for clean andrenewable energy resources.However,solar‐to‐fuel conversion efficiencies of current photocatalysts are not sufficient to meet commercial requirements.The narrow window of solar energy that can be used has been identified as a key reason behind such low photocatalytic reaction efficiencies.The use of photonic crystals,formed from multiple material components,has been demonstrated to be an effective way of improving light harvesting.Within these nanostructures,the slow‐photon effect,a manifestation of light‐propagation control,considerably enhances the interaction between light and the semiconductor components.This article reviews recent developments in the applications of photonic crystals to photocatalytic H2production and CO2reduction based on slow photons.These advances show great promise for improving light harvesting in solar‐energy conversion technologies.展开更多
This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (se...This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (semiconducting) materials to prepare hybrid materials. The semiconducting properties of the nanocarbons, and the possibility to have the band gap within the visible-light region through defect band engineering, introduction of light heteroatoms and control/manipulation of the curvature or surface functionalization are discussed. These materials are conceptually different from the 'classical' semiconducting photocatalysts, because semiconductor domains with tuneable characteristics are embedded in a conductive carbon matrix, with the presence of various functional groups (as C=0 groups) enhancing charge separation by trapping electrons. These nanocarbons open a range of new possibilities for photocatalysis both for energetic and environmental applications. The use of nanocarbons as quantum dots and photo luminescent materials was also analysed. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
CO2 photoreduction by semiconductors is of growing interest. Fabrication of oxygen-deficient surfaces is an important strategy for enhancing CO2 photoreduction activity. However, regeneration of the oxygen vacancies i...CO2 photoreduction by semiconductors is of growing interest. Fabrication of oxygen-deficient surfaces is an important strategy for enhancing CO2 photoreduction activity. However, regeneration of the oxygen vacancies in photocatalysts is still a problem since an oxygen vacancy will be filled up by the O atom from CO2 after the dissociation process. Herein, we have fabricated highly efficient BiOC1 nanoplates with photoinduced oxygen vacancies. Oxygen vacancies were easily regenerated by light irradiation due to the high oxygen atom density and low Bi~） bond energy even when the oxygen vacancies had been filled up by the O atom in the photocatalytic reactions. These oxygen vacancies not only enhanced the trapping capability for CO2, but also enhanced the efficiency of separation of electron-hole pairs, which resulted in the photocatalytic CO2 reduction under simulated solar light. Furthermore, the generation and recovery of the defects in the BiOC1 could be realized during the photocatalytic reduction of CO2 in water. The existence of photoinduced defects in thin BiOC1 nanoplates undoubtedly leads to new possibilities for the design of solar-driven bismuth based photocatalysts.展开更多
The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, blac...The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, black phosphorus quantum dots（BPQDs） were successfully dispersed on a graphitic carbon nitride（g-C3N4） support via a simple electrostatic attraction approach, and the activities of BP@g-C3N4 composites were evaluated for photocatalytic CO2 reduction. The BP@g-C3N4 composites displayed improved carrier separation efficiency and higher activities for photocatalytic CO2 reduction to CO（6.54 μmol g^-1h^-1 at the optimum BPQDs loading of 1 wt%） compared with pure g-C3N4（2.65 μmol g^-1h^-1）. This work thus identifies a novel approach towards metal free photocatalysts for CO2 photoreduction.展开更多
Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performa...Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO2 under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO2 NFs were found to exhibit enhanced performance compared to Pt-decorated TiO2 NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO2 NFs exhibited higher selectivity for methanol, typically producing -90 ppmg^-1.h^-1 methanol. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.展开更多
基金This work received fi nancial support from the National Natural Science Foundation of China(No.21633004).
文摘Visible light photocatalytic CO2 conversion is a promising solution to global warming and energy shortage.Herein,we build a well-designed bridge-like nanostructure,that is,the phosphonated Ru complex(RuP)light absorber–TiO2 bridge–Cu catalyst.In this nanostructure,brookite TiO2 serving as a bridge is spatially connected to the RuP and Cu on each of its sides and could thus physically separate the photoexcited holes and electrons over the RuP and Cu,respectively.Given its eff ective charge separation,this RuP–TiO2–Cu assembly exhibits superior CO2 photoreduction activity relative to RuP–SiO2–Cu under visible light irradiation(λ>420 nm).The catalytic activity is further optimized by adopting brookite TiO2 with various electronic band structures.Results reveal the rapid movement of electrons from the RuP through the conduction band of TiO2 and fi nally to the Cu surface.This property is crucial in CO2 photoreduction activity.
基金This work was jointly supported by the National Natural Science Foundation of China(51972288 and 51672258)the Fundamental Research Funds for the Central Universities(2652018290).
文摘Reduction of CO2to solar fuels by artificial photosynthesis technology has attracted considerable attention. However, insufficient separation of charge carriers and weak CO2adsorption hamper the photocatalytic CO2 reduction activity. Herein, we tackle these challenges by introducing oxygen vacancies (OVs) on the two-dimensional Bi4Ti3O12ultrathin nanosheets via a combined hydrothermal and postreduction process. Selective photodeposition experiment of Pt over Bi4Ti3O12discloses that the ultrathin structure shortens the migration distance of photo-induced electrons from bulk to the surface, benefiting the fast participation in the CO2reduction reaction. The introduction of OVs on ultrathin Bi4Ti3O12 nanosheets leads to enormous amelioration on surface state and electronic structure, thereby resulting in enhanced CO2adsorption, photoabsorption and charge separation efficiency. The photocatalytic experiments uncover that ultrathin Bi4Ti3O12nanosheets with OVs reveal a largely enhanced CO2photoreduction activity for producing CO with a rate of 11.7 lmol g-1h-1in the gas–solid system, 3.2 times higher than that of bulk Bi4Ti3O12. This work not only yields efficient ultrathin photocatalysts with OVs, but also furthers our understanding on enhancing CO2reduction via cooperative tactics.
文摘COphotoreduction is an attractive process which allows the storage of solar energy and synthesis of solar fuels. Many different photocatalytic systems have been developed, while the alternative photo-reactors are still insufficiently investigated. In this work, photoreduction of COwith HO into CHwas investigated in a modified concentrating solar reactor, using TiOand Pt/TiOas the catalysts. The TiOand Pt/TiOsamples were extensively characterized by different techniques including powder X-ray diffraction（XRD）, Nadsorption/desorption and UV–vis absorption. The catalytic performance of the TiOand Pt/TiOsamples in the gas phase was evaluated under unconcentrated and concentrated Xe-lamp light and nature solar light with different concentrating ratios. Various parameters of the reaction system and the catalysts were investigated and optimized to maximize the catalytic performance of COreduction system. Compared with the normal light irradiation, the TiOand Pt/TiOsamples show higher photocatalytic activity（about 6–7 times） for reducing COinto CHunder concentrated Xe-lamp light and nature solar light. In the range of experimental light intensity, it is found that the concentration of the light makes it suitable for the catalytic reaction, and increases the utilization efficiency of the TiOand Pt/TiOsamples while does not decrease the quantum efficiency.
基金This work was supported by the National Science Fund for Distinguished Young Scholars(21925204)the National Natural Science Foundation of China(U19A2015,21673214,U1732272)+5 种基金the National Key Research and Development Program of China(2019YFA-0405600)the Key Research Program of Frontier Sciences of the CAS(QYZDB-SSW-SLH017)the Fundamental Research Funds for the Central Universities,the USTC Research Funds of the Double First-Class Initiative(YD2340002002)the Taishan Scholar Program of Shandong Province of China(tsqn201909122)the China Postdoctoral Science Foundation(2019TQ0300)This work was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.
文摘Photocatalytic reduction of CO2 into value-added products is a promising strategy for mitigating environmental and energy problems simultaneously.Herein,we developed Au sheets with subtle grain boundaries on ultrathin Ni(OH)2 nanosheets as efficient photocatalysts for CO2 reduction.According to mechanistic studies,grain boundaries on the Au sheets served as electron trapping sites which enabled the optimization of electron-hole separation.Moreover,grain boundaries perturbed electron distribution,which assisted in stabilizing CO2^δ- and HCOO^* intermediates.As a result,the unique hybrid structure achieved a high rate of 75.2μmol g^-1h^-1 for CO2 photoreduction.This work demonstrates the importance of defect engineering in designing active photocatalysts and also provides insight into development of related photo-energy conversion schemes.
文摘The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.
基金the National Natural Science Foundation of China(Nos.U1707603,21878008,21625101,and U1507102,21922801)the Beijing Natural Science Foundation(Nos.2182047 and 2202036)the Fundamental Research Funds for the Central Universities(Nos.XK1802-6,XK1902,12060093063,and 2312018RC07).
文摘Visible-light-driven CO2 photoreduction to achieve renewable materials,such as syngas,hydrocarbons,and alcohols,is a key process that could relieve environmental problems and the energy crisis simultaneously.Reduction of syngas products with diff erent H2:CO proportions is highly expected to produce high value-added chemicals in the industry.However,the development of technologies employing long-wavelength irradiation to achieve CO2 photoreduction and simultaneous tuning of the resultant H2:CO proportion remains a challenging endeavor.In this work,we carried out interfacial engineering by designing a series of heterostructured layered double-hydroxide/MoS2 nanocomposites via electrostatic self-assembly.The syngas proportion(H 2:CO)obtained from CO2 photoreduction could be modulated from 1:1 to 9:1 by visible-light irradiation(λ>400 nm)under the control of the interface-rich heterostructures.This work provides a cost-eff ective strategy for solar-tofuel conversion in an artificial photosynthetic system and describes a novel route to produce syngas with targeted proportions.
文摘Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific functions.Herein,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the CO_(2) reduction catalyst[ReI(bpy)(CO)_(3)Cl]and the porphyrin photosensitizer as the monomeric building units.The light‐harvesting properties of the porphyrin itself,augmented by the extendedπ‐conjugated planar structure of 2D COF,enable H_(2)PReBpy‐COF the excellent light‐harvesting capability,efficient charge separation,and fast interfacial charge transfer.In addition,a large amount of uniformly distributed[ReI(bpy)(CO)_(3)Cl]units offer H_(2)PReBpy‐COF an excellent activity toward photocatalytic CO_(2) reduction with moderate selectivity and reusability.This study demonstrated a proof of concept in which the advantages of COFs and functional monomers are rationally integrated for photocatalytic solar fuel conversion.
基金the Ministry of Education (MOE), Universiti Kebangsaan Malaysia and Universiti Malaysia Pahang for financial support of this research under RAGS (RDU131418) and FRGS (RDU120112)
文摘The performance of CeO2-TiO2 photocatalyst for the photocatalytic reduction of CO2 into methanol was studied under visible light irradiation. The as-prepared catalysts were characterized for their structural, textural and optical properties using X-ray diffraction（XRD）, field emission scanning electron microscopy（FESEM）, X-ray photoelectron spectroscopy（XPS）, nitrogen physisorption analysis, UV-vis spectroscopy and photoluminescence（PL） spectroscopy. The characterization results indicated that the presence of CeO2 stabilized the anatase phase of TiO2, decreased its crystallite size, increased the surface area, reduced the band gap energy and lowered the rate of electron-hole pair recombination. The CeO2-TiO2 photocatalyst showed an increased methanol yield of 18.6 μmol/g under visible light irradiation, compared to the bare TiO2（6.0 μmol/g）.
基金supported by the National Natural Science Foundation of China(21776117 and 21576125)China Postdoctoral Science Foundation(2017M611716 and 2017M611734)+1 种基金Six Talent Peaks Project in Jiangsu Province(XCL-014)Zhenjiang Science and Technology Program(SH2016012)~~
文摘A series of Au/g-C3N4(Au/CN)nanocomposites were successfully prepared,where g-C3N4 nanosheets(CN NSs)served as a substrate for the growth of different sized Au nanoparticles(Au NPs)using the constant temperature bath-reduction method.The effect of Au NP size on electron transfer efficiency between the interfaces of the nanocomposite was studied.The three-dimensional finite-difference time-domain results revealed that larger Au NPs showed increased strength of the localized surface plasmon resonance effect.An increased number of high-energy electrons were available for transfer from Au NPs to CN under the visible light irradiation,inhibiting electron transfer from CN to Au NPs.Photoelectrochemical performance analysis showed that smaller Au NPs exhibited higher separation efficiency of the electron-hole pairs photo-generated with reasonable distribution density.These results are favorable for the improvement of photocatalytic performance.Compared to other nanocomposites,the 3-Au/CN sample(prepared using 3 mL HAuCl4 solution)with reasonable distribution density and small Au NPs exhibited the best photodegradation activity(92.66%)of RhB in 30 min under the visible light irradiation and photoreduction performance of CO2 to CO and CH4 with yields of 77.5 and 38.5μmol/g,respectively,in 8 h under UV light irradiation.Considering the experimental results in the context of the literature,a corresponding size-dependent photocatalytic mechanism was proposed.
文摘Converting solar energy into hydrogen and hydrocarbon fuels through photocatalytic H2production and CO2photoreduction is a highly promising approach to address growing demand for clean andrenewable energy resources.However,solar‐to‐fuel conversion efficiencies of current photocatalysts are not sufficient to meet commercial requirements.The narrow window of solar energy that can be used has been identified as a key reason behind such low photocatalytic reaction efficiencies.The use of photonic crystals,formed from multiple material components,has been demonstrated to be an effective way of improving light harvesting.Within these nanostructures,the slow‐photon effect,a manifestation of light‐propagation control,considerably enhances the interaction between light and the semiconductor components.This article reviews recent developments in the applications of photonic crystals to photocatalytic H2production and CO2reduction based on slow photons.These advances show great promise for improving light harvesting in solar‐energy conversion technologies.
基金Financial support from the Italian MIUR gh the PRIN Project 2015K7FZLH SMARTNESS "Solar driven chemistry:new materials for photo- and electro-catalysis"SINCHEM,a Joint Doctorate programme selected under the Erasmus Mundus Action 1 Programme (FPA 2013-0037)
文摘This perspective paper introduces the concept that nanocarbons and related materials such as carbon dots are an interesting intrinsic photocatalytic semiconducting material, and not only a modifier of the existing (semiconducting) materials to prepare hybrid materials. The semiconducting properties of the nanocarbons, and the possibility to have the band gap within the visible-light region through defect band engineering, introduction of light heteroatoms and control/manipulation of the curvature or surface functionalization are discussed. These materials are conceptually different from the 'classical' semiconducting photocatalysts, because semiconductor domains with tuneable characteristics are embedded in a conductive carbon matrix, with the presence of various functional groups (as C=0 groups) enhancing charge separation by trapping electrons. These nanocarbons open a range of new possibilities for photocatalysis both for energetic and environmental applications. The use of nanocarbons as quantum dots and photo luminescent materials was also analysed. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
文摘CO2 photoreduction by semiconductors is of growing interest. Fabrication of oxygen-deficient surfaces is an important strategy for enhancing CO2 photoreduction activity. However, regeneration of the oxygen vacancies in photocatalysts is still a problem since an oxygen vacancy will be filled up by the O atom from CO2 after the dissociation process. Herein, we have fabricated highly efficient BiOC1 nanoplates with photoinduced oxygen vacancies. Oxygen vacancies were easily regenerated by light irradiation due to the high oxygen atom density and low Bi~） bond energy even when the oxygen vacancies had been filled up by the O atom in the photocatalytic reactions. These oxygen vacancies not only enhanced the trapping capability for CO2, but also enhanced the efficiency of separation of electron-hole pairs, which resulted in the photocatalytic CO2 reduction under simulated solar light. Furthermore, the generation and recovery of the defects in the BiOC1 could be realized during the photocatalytic reduction of CO2 in water. The existence of photoinduced defects in thin BiOC1 nanoplates undoubtedly leads to new possibilities for the design of solar-driven bismuth based photocatalysts.
基金supported by the National Natural Science Foundation of China (51502146, U1404506, 21671113, 51772305, 51572270, and U1662118)the International Partnership Program of Chinese Academy of Sciences (GJHZ1819)+1 种基金the Royal Society-Newton Advanced Fellowship (NA170422)supported by Open Fund (PEBM201702) of Key Laboratory for Photonic and Electric Bandgap Materials, Ministry of Education (Harbin Normal University)
文摘The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, black phosphorus quantum dots（BPQDs） were successfully dispersed on a graphitic carbon nitride（g-C3N4） support via a simple electrostatic attraction approach, and the activities of BP@g-C3N4 composites were evaluated for photocatalytic CO2 reduction. The BP@g-C3N4 composites displayed improved carrier separation efficiency and higher activities for photocatalytic CO2 reduction to CO（6.54 μmol g^-1h^-1 at the optimum BPQDs loading of 1 wt%） compared with pure g-C3N4（2.65 μmol g^-1h^-1）. This work thus identifies a novel approach towards metal free photocatalysts for CO2 photoreduction.
文摘Nanosized metal （Pt or Pd）-decorated TiO2 nanofibers （NFs） were synthesized by a wet impregnation method. CdSe quantum dots （QDs） were then anchored onto the metal-decorated TiO2 NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO2 under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO2 NFs were found to exhibit enhanced performance compared to Pt-decorated TiO2 NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO2 NFs exhibited higher selectivity for methanol, typically producing -90 ppmg^-1.h^-1 methanol. The CO2 photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.
