Aldehyde group-functionalized [Ru(bpy)2L](PF6)2 catalyst was prepared and immobilized onto the mesoporous silica nanoparticles to act as a heterogeneous catalyst for the selective oxidation of thioanisole to methy...Aldehyde group-functionalized [Ru(bpy)2L](PF6)2 catalyst was prepared and immobilized onto the mesoporous silica nanoparticles to act as a heterogeneous catalyst for the selective oxidation of thioanisole to methyl phenyl sulfoxide under visible light.The heterogeneous catalyst can be easily recovered by simple centrifugation without chemical treatment,exhibiting comparable catalytic efficiency with homogeneous ones and no decrease in catalytic efficiency after at least 5 cycles.展开更多
The present work suggested the use of waste oil palm frond as an alternative precursor for nitrogendoped carbon quantum dots(NCQDs)and proposed a straightforward in-situ hydrothermal method for the preparation of NCQD...The present work suggested the use of waste oil palm frond as an alternative precursor for nitrogendoped carbon quantum dots(NCQDs)and proposed a straightforward in-situ hydrothermal method for the preparation of NCQDs/TiO_(2)nanocomposites.The elemental composition,morphological,structural and optical characteristics of NCQDs/TiO_(2)nanocomposites have been comprehensively investigated.The successful grafting of NCQDs on TiO_(2)matrix was confirmed by the formation of Ti AOAC bond and the electronic coupling between theπ-states of NCQDs and the conduction band of TiO_(2).For the first time,the oil palm frond-derived NCQDs/TiO_(2)was adopted in the photodegradation of methylene blue(MB)under visible-light irradiation.As a result,the photocatalytic efficiency of NCQDs/TiO_(2)nanocomposites(86.16%)was 2.85 times higher than its counterpart TiO_(2)(30.18%).The enhanced performance of nanocomposites was attributed to the pivotal roles of NCQDs serving as electron mediator and visiblelight harvester.Besides,the optimal NCQDs loading was determined at 4 ml while the removal efficiency of NCQDs/TiO_(2)-4 was the highest at a catalyst dosage of 1 g.L^(-1)under alkaline condition.This research work is important as it proposed a new insight to the preparation of biomass-based NCQDs/TiO_(2)using a facile synthetic method,which offers a green and sustainable water remediation technology.展开更多
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
Due to the low concentration of indoor air contaminants, photocatalytic technology shows low efficiency for indoor air purification. The application of TiO2 for photocatalytic removal of formaldehyde is limited, becau...Due to the low concentration of indoor air contaminants, photocatalytic technology shows low efficiency for indoor air purification. The application of TiO2 for photocatalytic removal of formaldehyde is limited, because TiO2 can only absorb ultraviolet (UV) light. Immobilization of TiO2 nanoparticles on the surface of graphene can improve the visible light photocatalytic activity and the adsorption capacity. In this study, rGO (reduced graphene oxide)/TiO2 was synthesized through a hydrotherrnal method using titanium tetrabutoxide and graphene oxide as precursors, and was used for the degradation of low concentration formaldehyde in indoor air under visible light illumination. Characterization of the crystalline structure and morphology of rGO/TiO2 revealed that most GO was reduced to rGO during the hydrothermal treatment, and anatase TiO2 nanoparticles (with particle size of 15-30 nm) were dispersed well on the surface of the rGO sheets, rGO/TiO2 exhibited excellent photocatalyfic activity for degradation of formaldehyde in indoor air and this can be attributed to the role ofrGO, which can act as the electron sink and transporter for separating photo-generated electron-hole pairs through interfacial charge transfer. Furthermore, rGO could adsorb formaldehyde molecules from air to produce a high concentration of formaldehyde on the surface of rGO/ TiO2. Under visible light irradiation for 240 min, the concentration of formaldehyde could be reduced to 58.5 ppbV. rGO/TiO2 showed excellent moisture-resistance behavior, and after five cycles, rGO/TiO2 maintained high photocatalytic activity for the removal of formaldehyde (84.6%). This work suggests that the synthesized rGO/TiO2 is a promising photocatalyst for indoor formaldehyde removal.展开更多
Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime go...Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.展开更多
Hollow microspheres of two bismuth oxychlorides, BiOC1 and Bi24031Cl10, were successfully synthesized using carbonaceous microsphere sacrificial templates. The phase evolution from BiOC1 to Bi24031Cl10 was easily real...Hollow microspheres of two bismuth oxychlorides, BiOC1 and Bi24031Cl10, were successfully synthesized using carbonaceous microsphere sacrificial templates. The phase evolution from BiOC1 to Bi24031Cl10 was easily realized by heating the former at 600 ℃. With a uniform diameter of about 200 nm, an average shell thickness of 40 nm, and basic nanosheets of 〈20 nm, the hollow microspheres of both BLOC1 and Bi24031Cl10 showed high visible light photocatalytic activity towards the degradation of Rhodamine B (RhB). Besides the effective photo- sensitization process and efficient photointroduced carrier separation, the high photocatalytic activity was believed to result from their hollow-structure- dependent large visible light absorption. Moreover, as a chlorine-deficient analogue, the Bi24031Cl10 hollow spheres possessed a narrower band gap, more dispersive band structure, and higher photocarrier conversion efficiency, which further helped them to exhibit better photocatalytic activity.展开更多
Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three...Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three prime enhancement mechanisms for plasmon-enhanced photocatalytic WS,and then some state-of-the-art representative studies are introduced according to different enhancement mechanisms.Furthermore,the design parameters of plasmonic-metal/semiconductor photocatalysts are discussed in detail,focusing on the effect of shape,size and geometric position of metallic nanostructures on the photocatalytic activity of visible light-driven WS.Finally,the challenges and perspectives for plasmon-enhanced solar WS are proposed.展开更多
TiO_(2)-ZnO nanocomposites were synthesized by varying Ti:Zn molar ratio from 1:0.1(TZ-1:0.1)to 1:1(TZ-1:1).With increase in Zn content,from TZ-1:0.1 to TZ-1:0.2,anatase transformed to rutile phase.TZ-1:0.3,which cont...TiO_(2)-ZnO nanocomposites were synthesized by varying Ti:Zn molar ratio from 1:0.1(TZ-1:0.1)to 1:1(TZ-1:1).With increase in Zn content,from TZ-1:0.1 to TZ-1:0.2,anatase transformed to rutile phase.TZ-1:0.3,which contained a blend of phases,including rutile and anatase TiO_(2),ZnO,and zinc titanates,exhibited the narrowest bandgap(2.5±0.1 e V),and showed the highest photocatalytic activity.TZ-1:1 was predominated by zinc titanates.All the nanocomposites exhibited narrower bandgaps compared to pure TiO_(2)nanoparticles,facilitating visible light activity.This study was designed to explore whether a method targeting the removal of a specific crystalline phase(anatase)influenced the properties and photocatalytic activity of the nanocomposite.Selective dissolution not only removed anatase phase,but also led to significant loss of crystallinity,widened the bandgap,and adversely affected photocatalytic performance,in nanocomposites that contained>80%anatase phase(TZ-1:0.1 and TZ-1:0.2).However,in nanocomposites that contained less of anatase phase(TZ-1:0.3and TZ-1:1),the morphology,bandgap,crystallinity,and the extent of photocatalytic activity at the end of 240 min remained largely unaffected.Photocatalytic activity in TZ-1:0.3 and TZ-1:1 originated from a blend of phases comprising of less photocatalytically active phases,such as rutile TiO_(2),Zn TiO3,and Zn2TiO4,rather than from the anatase phase.The Ti:Zn molar ratio controlled the phases present in TiO_(2)-ZnO nanocomposites,which,in turn,controlled the physicochemical properties and visible light activity.Thus,in nanocomposites that contained a mix of several phases,the properties and photocatalytic activity were not dependent on anatase phase.展开更多
In this work, we have shown that mining waste derived Fe^3+can be used to enhance the photocatalytic activity of TiO2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO2 phot...In this work, we have shown that mining waste derived Fe^3+can be used to enhance the photocatalytic activity of TiO2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO2 photocatalytic waste water treatment efficiency. An organic linker mediated route was utilized to create a composite of TiO2 and biogenic jarosite. Evidence of Fe/O/Ti bonding in the TiO2/jarosite composite was apparent from the FTIR, EFTEM, EELS and ELNEFS analysis. The as prepared material showed enhanced photocatalytic activity compared to pristine TiO2, biogenic jarosite and mechanically mixed sample of jarosite and TiO2 under both simulated and natural solar irradiation. The prepared material can reduce the electrical energy consumption by 4 times compared to pristine P25 for degradation of organic pollutant in water. The material also showed good recyclability. Results obtained from sedimentation experiments showed that the larger sized jarosite material provided the surface to TiO2 nanoparticles, which increases the settling rate of the materials. This allowed simple and efficient recovery of the catalyst from the reaction system after completion of photocatalysis. Enhanced photocatalytic activity of the composite material was due to effective charge transfer between TiO2 and jarosite derived Fe^3+as was shown from the EELS and ELNEFS. Generation of OHU was supported by photoluminesence(PL) experiments.展开更多
A novel visible light-active photocatalyst formulation(NdT/OP) was obtained by supporting N-doped TiO2(NdT) particles on up-conversion luminescent organic phosphors(OP). The photocatalytic activity of such catal...A novel visible light-active photocatalyst formulation(NdT/OP) was obtained by supporting N-doped TiO2(NdT) particles on up-conversion luminescent organic phosphors(OP). The photocatalytic activity of such catalysts was evaluated for the mineralization process of spiramycin in aqueous solution. The effect of NdT loading in the range 15–60 wt.% on bulk and surface characteristics of NdT/OP catalysts was investigated by several chemicophysical characterization techniques. The photocatalytic performance of NdT/OP catalysts in the removal of spyramicin from aqueous solution was assessed through photocatalytic tests under visible light irradiation. Total organic carbon(TOC) of aqueous solution,and CO and CO2 gas concentrations evolved during the photodegradation were analyzed. A dramatic enhancement of photocatalytic activity of the photostructured visible active NdT/OP catalysts,compared to NdT catalyst,was observed. Only CO2 was detected in gas-phase during visible light irradiation,proving that the photocatalytic process is effective in the mineralization of spiramycin,reaching very high values of TOC removal. The photocatalyst NdT/OP at 30 wt.% of NdT loading showed the highest photocatalytic activity(58%of TOC removed after 180 min irradiation against only 31% removal after 300 min of irradiation of NdT). We attribute this enhanced activity to the high effectiveness in the utilization of visible light through improved light harvesting and exploiting. OP particles act as "photoactive support",able to be excited by the external visible light irradiation,and reissue luminescence of wavelength suitable to promote NdT photomineralization activity.展开更多
Cr(Ⅵ) is a common heavy metal ion, which will seriously harm human body and environment.Therefore, the removal of Cr(Ⅵ) has become an attractive topic.In this work, cinder was used as a raw material to synthesize a ...Cr(Ⅵ) is a common heavy metal ion, which will seriously harm human body and environment.Therefore, the removal of Cr(Ⅵ) has become an attractive topic.In this work, cinder was used as a raw material to synthesize a nanoneedle material: γ-(AlOOH@FeOOH)(γ-Al@Fe).The physicochemical properties of γ-Al@Fe were thoroughly characterized, and its effectiveness as a catalyst for photocatalytic reduction of Cr(Ⅵ) was evaluated.The results showed that Cr(Ⅵ) could be efficiently reduced by γ-Al@Fe in the presence of tartaric acid(TA) under visible light.The variable factors on the reaction were investigated in detail, and the results showed that under optimal conditions(γ-Al@Fe 0.4 g/L, TA 0.6 g/L, pH 2), Cr(Ⅵ)was completely reduced within 7 min.Besides, scavenger experiments and EPR proved that O_(2)^(·-) and CO_(2)^(·-) played a significant role in the photocatalytic reduction of Cr(Ⅵ).TA acts as a sacrificial agent to trap the holes and generate strong reducing free radicals: CO_(2)^(·-).Dissolving O_(2) could react with electrons to generate O_(2)^(·-).This work discussed the performance and mechanism of photocatalytic reduction of Cr(Ⅵ) in detail, which provided a new idea for the resource utilization of solid waste and the treatment of heavy metal sewage.展开更多
Ce-TiO2/CA(carbon aerogel) electrode was prepared by sol impregnation approach. The XRD(X-ray diffraction) and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the op...Ce-TiO2/CA(carbon aerogel) electrode was prepared by sol impregnation approach. The XRD(X-ray diffraction) and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO(fluorine-doped tin oxide). The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting metho...Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.51021003,51273194,21104075,21174143).
文摘Aldehyde group-functionalized [Ru(bpy)2L](PF6)2 catalyst was prepared and immobilized onto the mesoporous silica nanoparticles to act as a heterogeneous catalyst for the selective oxidation of thioanisole to methyl phenyl sulfoxide under visible light.The heterogeneous catalyst can be easily recovered by simple centrifugation without chemical treatment,exhibiting comparable catalytic efficiency with homogeneous ones and no decrease in catalytic efficiency after at least 5 cycles.
基金the funding provided by Universiti Tunku Abdul Rahman Research fund(IPSR/RMC/UTARRF/2020-C2/C06)Centre for Photonics and Advanced Materials Research(CPAMR,UTAR)for their support。
文摘The present work suggested the use of waste oil palm frond as an alternative precursor for nitrogendoped carbon quantum dots(NCQDs)and proposed a straightforward in-situ hydrothermal method for the preparation of NCQDs/TiO_(2)nanocomposites.The elemental composition,morphological,structural and optical characteristics of NCQDs/TiO_(2)nanocomposites have been comprehensively investigated.The successful grafting of NCQDs on TiO_(2)matrix was confirmed by the formation of Ti AOAC bond and the electronic coupling between theπ-states of NCQDs and the conduction band of TiO_(2).For the first time,the oil palm frond-derived NCQDs/TiO_(2)was adopted in the photodegradation of methylene blue(MB)under visible-light irradiation.As a result,the photocatalytic efficiency of NCQDs/TiO_(2)nanocomposites(86.16%)was 2.85 times higher than its counterpart TiO_(2)(30.18%).The enhanced performance of nanocomposites was attributed to the pivotal roles of NCQDs serving as electron mediator and visiblelight harvester.Besides,the optimal NCQDs loading was determined at 4 ml while the removal efficiency of NCQDs/TiO_(2)-4 was the highest at a catalyst dosage of 1 g.L^(-1)under alkaline condition.This research work is important as it proposed a new insight to the preparation of biomass-based NCQDs/TiO_(2)using a facile synthetic method,which offers a green and sustainable water remediation technology.
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financially supported by China Postdoctoral Science Foundation(No.2016M592496)Natural Science Foundation of Guangdong Province,China(Nos.2017A030310279,2014A030310431)+1 种基金National Natural Science Foundation of China(Nos.41501319,91645119,21207039,U1201231,51378218,51108187 and 50978103)Guangzhou science and technology plan(No.201607010095)
文摘Due to the low concentration of indoor air contaminants, photocatalytic technology shows low efficiency for indoor air purification. The application of TiO2 for photocatalytic removal of formaldehyde is limited, because TiO2 can only absorb ultraviolet (UV) light. Immobilization of TiO2 nanoparticles on the surface of graphene can improve the visible light photocatalytic activity and the adsorption capacity. In this study, rGO (reduced graphene oxide)/TiO2 was synthesized through a hydrotherrnal method using titanium tetrabutoxide and graphene oxide as precursors, and was used for the degradation of low concentration formaldehyde in indoor air under visible light illumination. Characterization of the crystalline structure and morphology of rGO/TiO2 revealed that most GO was reduced to rGO during the hydrothermal treatment, and anatase TiO2 nanoparticles (with particle size of 15-30 nm) were dispersed well on the surface of the rGO sheets, rGO/TiO2 exhibited excellent photocatalyfic activity for degradation of formaldehyde in indoor air and this can be attributed to the role ofrGO, which can act as the electron sink and transporter for separating photo-generated electron-hole pairs through interfacial charge transfer. Furthermore, rGO could adsorb formaldehyde molecules from air to produce a high concentration of formaldehyde on the surface of rGO/ TiO2. Under visible light irradiation for 240 min, the concentration of formaldehyde could be reduced to 58.5 ppbV. rGO/TiO2 showed excellent moisture-resistance behavior, and after five cycles, rGO/TiO2 maintained high photocatalytic activity for the removal of formaldehyde (84.6%). This work suggests that the synthesized rGO/TiO2 is a promising photocatalyst for indoor formaldehyde removal.
基金supported by the National Natural Science Foundation of China(U1663225,21805280 and 21805220)the Youth Innovation Foundation of Xiamen City:3502Z20206085+4 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R52)The Opening Project of PCOSS,Xiamen University,201907the program of introducing Talents of discipline to Universities-111 Project(Grant No.B20002)the project“Depollut Air”of Interreg V France-Wallonie-Vlaanderenthe financial support from the China Scholarship Council(CSC)。
文摘Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China (Nos. 21271021 and 51472025) and Program for Changjiang Scholars and Innovative Research Team in University (No. IRT 1207).
文摘Hollow microspheres of two bismuth oxychlorides, BiOC1 and Bi24031Cl10, were successfully synthesized using carbonaceous microsphere sacrificial templates. The phase evolution from BiOC1 to Bi24031Cl10 was easily realized by heating the former at 600 ℃. With a uniform diameter of about 200 nm, an average shell thickness of 40 nm, and basic nanosheets of 〈20 nm, the hollow microspheres of both BLOC1 and Bi24031Cl10 showed high visible light photocatalytic activity towards the degradation of Rhodamine B (RhB). Besides the effective photo- sensitization process and efficient photointroduced carrier separation, the high photocatalytic activity was believed to result from their hollow-structure- dependent large visible light absorption. Moreover, as a chlorine-deficient analogue, the Bi24031Cl10 hollow spheres possessed a narrower band gap, more dispersive band structure, and higher photocarrier conversion efficiency, which further helped them to exhibit better photocatalytic activity.
基金Financial support from the Natural Sciences and Engineering Research Council of Canada(RGPIN-2015-06756)Canada Research Chairs Program(950-212323)+3 种基金le Fonds de recherche du Quebec-Nature et technologies(FRQNT)is greatly appreciated.In addition,Q.Zhang acknowledges the support under State Scholarship Fund from the China Scholarship Council(CSC,NO.201506220152)D.Thrithamarassery Gangadharan acknowledges the support from FRQNT Merit scholarship program for foreign students(199772)Dr.Z.Xu acknowledges the National Natural Science Foundation of China(NSFC 51402198)Natural Science Foundation of Liaoning Province(201602592)for financial support.
文摘Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three prime enhancement mechanisms for plasmon-enhanced photocatalytic WS,and then some state-of-the-art representative studies are introduced according to different enhancement mechanisms.Furthermore,the design parameters of plasmonic-metal/semiconductor photocatalysts are discussed in detail,focusing on the effect of shape,size and geometric position of metallic nanostructures on the photocatalytic activity of visible light-driven WS.Finally,the challenges and perspectives for plasmon-enhanced solar WS are proposed.
基金provided by Department of Science and Technology,New Delhi,India,under the Water Technology Initiative(WTI)scheme(Project code:DST/TM/WTI/2K15/101(G)).
文摘TiO_(2)-ZnO nanocomposites were synthesized by varying Ti:Zn molar ratio from 1:0.1(TZ-1:0.1)to 1:1(TZ-1:1).With increase in Zn content,from TZ-1:0.1 to TZ-1:0.2,anatase transformed to rutile phase.TZ-1:0.3,which contained a blend of phases,including rutile and anatase TiO_(2),ZnO,and zinc titanates,exhibited the narrowest bandgap(2.5±0.1 e V),and showed the highest photocatalytic activity.TZ-1:1 was predominated by zinc titanates.All the nanocomposites exhibited narrower bandgaps compared to pure TiO_(2)nanoparticles,facilitating visible light activity.This study was designed to explore whether a method targeting the removal of a specific crystalline phase(anatase)influenced the properties and photocatalytic activity of the nanocomposite.Selective dissolution not only removed anatase phase,but also led to significant loss of crystallinity,widened the bandgap,and adversely affected photocatalytic performance,in nanocomposites that contained>80%anatase phase(TZ-1:0.1 and TZ-1:0.2).However,in nanocomposites that contained less of anatase phase(TZ-1:0.3and TZ-1:1),the morphology,bandgap,crystallinity,and the extent of photocatalytic activity at the end of 240 min remained largely unaffected.Photocatalytic activity in TZ-1:0.3 and TZ-1:1 originated from a blend of phases comprising of less photocatalytically active phases,such as rutile TiO_(2),Zn TiO3,and Zn2TiO4,rather than from the anatase phase.The Ti:Zn molar ratio controlled the phases present in TiO_(2)-ZnO nanocomposites,which,in turn,controlled the physicochemical properties and visible light activity.Thus,in nanocomposites that contained a mix of several phases,the properties and photocatalytic activity were not dependent on anatase phase.
基金supported by the National Research Foundation(No.88220,and 91510)
文摘In this work, we have shown that mining waste derived Fe^3+can be used to enhance the photocatalytic activity of TiO2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO2 photocatalytic waste water treatment efficiency. An organic linker mediated route was utilized to create a composite of TiO2 and biogenic jarosite. Evidence of Fe/O/Ti bonding in the TiO2/jarosite composite was apparent from the FTIR, EFTEM, EELS and ELNEFS analysis. The as prepared material showed enhanced photocatalytic activity compared to pristine TiO2, biogenic jarosite and mechanically mixed sample of jarosite and TiO2 under both simulated and natural solar irradiation. The prepared material can reduce the electrical energy consumption by 4 times compared to pristine P25 for degradation of organic pollutant in water. The material also showed good recyclability. Results obtained from sedimentation experiments showed that the larger sized jarosite material provided the surface to TiO2 nanoparticles, which increases the settling rate of the materials. This allowed simple and efficient recovery of the catalyst from the reaction system after completion of photocatalysis. Enhanced photocatalytic activity of the composite material was due to effective charge transfer between TiO2 and jarosite derived Fe^3+as was shown from the EELS and ELNEFS. Generation of OHU was supported by photoluminesence(PL) experiments.
文摘A novel visible light-active photocatalyst formulation(NdT/OP) was obtained by supporting N-doped TiO2(NdT) particles on up-conversion luminescent organic phosphors(OP). The photocatalytic activity of such catalysts was evaluated for the mineralization process of spiramycin in aqueous solution. The effect of NdT loading in the range 15–60 wt.% on bulk and surface characteristics of NdT/OP catalysts was investigated by several chemicophysical characterization techniques. The photocatalytic performance of NdT/OP catalysts in the removal of spyramicin from aqueous solution was assessed through photocatalytic tests under visible light irradiation. Total organic carbon(TOC) of aqueous solution,and CO and CO2 gas concentrations evolved during the photodegradation were analyzed. A dramatic enhancement of photocatalytic activity of the photostructured visible active NdT/OP catalysts,compared to NdT catalyst,was observed. Only CO2 was detected in gas-phase during visible light irradiation,proving that the photocatalytic process is effective in the mineralization of spiramycin,reaching very high values of TOC removal. The photocatalyst NdT/OP at 30 wt.% of NdT loading showed the highest photocatalytic activity(58%of TOC removed after 180 min irradiation against only 31% removal after 300 min of irradiation of NdT). We attribute this enhanced activity to the high effectiveness in the utilization of visible light through improved light harvesting and exploiting. OP particles act as "photoactive support",able to be excited by the external visible light irradiation,and reissue luminescence of wavelength suitable to promote NdT photomineralization activity.
基金supported by the National Natural Science Foundation of China (Nos.51672077, 51872089)。
文摘Cr(Ⅵ) is a common heavy metal ion, which will seriously harm human body and environment.Therefore, the removal of Cr(Ⅵ) has become an attractive topic.In this work, cinder was used as a raw material to synthesize a nanoneedle material: γ-(AlOOH@FeOOH)(γ-Al@Fe).The physicochemical properties of γ-Al@Fe were thoroughly characterized, and its effectiveness as a catalyst for photocatalytic reduction of Cr(Ⅵ) was evaluated.The results showed that Cr(Ⅵ) could be efficiently reduced by γ-Al@Fe in the presence of tartaric acid(TA) under visible light.The variable factors on the reaction were investigated in detail, and the results showed that under optimal conditions(γ-Al@Fe 0.4 g/L, TA 0.6 g/L, pH 2), Cr(Ⅵ)was completely reduced within 7 min.Besides, scavenger experiments and EPR proved that O_(2)^(·-) and CO_(2)^(·-) played a significant role in the photocatalytic reduction of Cr(Ⅵ).TA acts as a sacrificial agent to trap the holes and generate strong reducing free radicals: CO_(2)^(·-).Dissolving O_(2) could react with electrons to generate O_(2)^(·-).This work discussed the performance and mechanism of photocatalytic reduction of Cr(Ⅵ) in detail, which provided a new idea for the resource utilization of solid waste and the treatment of heavy metal sewage.
基金Project supported jointly by the Foundation of He'nan Educational Committee(15A150071)
文摘Ce-TiO2/CA(carbon aerogel) electrode was prepared by sol impregnation approach. The XRD(X-ray diffraction) and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO(fluorine-doped tin oxide). The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.
基金the National Natural Science Foundation of China(Nos.21103024,61171008)Natural Science Foundation of Zhejiang Province(No.LY19B060006)+1 种基金National Key Research and Development Program of China(No.2018YFB1502900)Technology Development Project of Jiaxing University(No.70518047)。
文摘Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.