G-C3N4 was supported on the surface of foamed ceramic,and the g-C3N4@foamed ceramic was packed in the photocatalytic reactor in a layered manner.Effects of urea and H2O2 concentration on NO conversion were investigate...G-C3N4 was supported on the surface of foamed ceramic,and the g-C3N4@foamed ceramic was packed in the photocatalytic reactor in a layered manner.Effects of urea and H2O2 concentration on NO conversion were investigated.Pulse experiments were carried out to investigate the change of NO conversion with time under different concentrations of H2O2.The contribution of each route that NO converted and the selectivities of products were calculated.Results showed that the photo-reduction of NO accounted for 2%,and the photo-oxidation of NO accounted for 14%,and the rest was absorbed by the humidifier.Products include ammonia(NH+4-N),nitrogen(N2),nitrite(NO-2-N)and nitrate(NO-3-N),of which N2 accounted for 9%.展开更多
In DMSO/water(4:1),photolysis of the dihydroxy-Sn(IV)-rnesoporphyrin dimethyl ester (SnP)/methyl viologen(MV^(2+))/ethylene diamine tetraacetic acid(EDTA)ternary system produces methyl viologen cation radical with a q...In DMSO/water(4:1),photolysis of the dihydroxy-Sn(IV)-rnesoporphyrin dimethyl ester (SnP)/methyl viologen(MV^(2+))/ethylene diamine tetraacetic acid(EDTA)ternary system produces methyl viologen cation radical with a quantum yield of 0.67,much higher than that of systems with other metal complexes of rnesoporphyrin dimethyl ester.Neither EDTA nor MV^(2+) quenches the stationary fluorescence of SnP,implying that the reaction does not take place at the singlet state.With flash photolysis we obtain the T-T absorption spectrum of SnP(λ_(max)-440 nm).By following the decay of this absorption,the triplet life time of SnP is estimated to be 41 μs.The life time is related to the concentration of either MV^(2+) or EDTA.Good linear relationships are obtained by plotting τ_0/τ vs.the concentration of MV^(2+) or EDTA(Stern-Volmer plot),from which we determine the quenching constants:k_q(MV^(2+))=5.5×10~7 mol^(-7) s^(-1);kq(EDTA)=2.7×10~7 mol^(-1),s^(-1).The data suggests that upon photolysis of the above ternary system,both oxidative quenching and reductive quenching of the triplet state of the sensitizer are occurring.From the measured phosphorescence spectrum(λ_(max) 704nm)and the ground state redox potentials (E_(1/2)^(red)～-0.84V,E_(1/2)^(ox)～ Ag/AgCl,KCl(sat.)),we obtain the redox potential of triplet SnP to be E (P^+/P)～-0.33 V, E(P/P-)～+0.92 V.Matching this data with the redox potential of MV^(2+) and EDTA,we establish the fact that during the photolysis of the SnP/MV^(2+)/EDTA ternary system,both oxidative and reductive quenching are thermodynamically favorable processes.This is also the reason why the SnP sensitized reaction is much more efficient relative to other mesoporphyrin derivatives.展开更多
A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi ...A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.展开更多
As a novel alternative to traditional perfluoroalkyl substances(PFASs),including perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),hexafluoroproplyene oxide trimer acid(HFPO-TA)has been detected worldwid...As a novel alternative to traditional perfluoroalkyl substances(PFASs),including perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),hexafluoroproplyene oxide trimer acid(HFPO-TA)has been detected worldwide in surface water.Moreover,recent researches have demonstrated that HFPO-TA has stronger bioaccumulation potential and higher hepatotoxicity than PFOA.To treat these contaminants e.g.PFOA and PFOS,some photochemical techniques by adding exogenous substances had been reported.However,there is still no report for the behavior of HFPO-TA itself under direct UV irradiation.The current study investigated the photo-transformation of HFPO-TA under UV irradiation in aqueous solution.After 72 hr photoreaction,75%degradation ratio and 25%defluorination ratio were achieved under ambient condition.Reducing active species,i.e.,hydrated electrons and active hydrogen atoms,generated from water splitting played dominant roles in degradation of HFPO-TA,which was confirmed by different effects of reaction atmospheres and quenching experiments.A possible degradation pathway was proposed based on the products identification and theoretical calculations.In general,HFPO-TA would be transformed into shorter-chain PFASs,including hexafluoropropylene oxide dimer acid(HFPODA),perfluoropropionic acid(PFA)and trifluoroacetate(TFA).This research provides basic information for HFPO-TA photodegradation process and is essential to develop novel remediation techniques for HFPO-TA and other alternatives with similar structures.展开更多
In order to develop efficient photocatalysts,great efforts have been made to reduce hexavalent chromium to trivalent chromium.The photocatalytic efficiency of this reduction depends largely on the adsorption and diffu...In order to develop efficient photocatalysts,great efforts have been made to reduce hexavalent chromium to trivalent chromium.The photocatalytic efficiency of this reduction depends largely on the adsorption and diffusion of hexavalent chromium ions on the surface of the photocatalyst.In this paper,polyanilineTiO2 composite can effectively improve the photocatalytic reduction performance and stability of hexavalent chromium ion.The effect of polyaniline(PANI) thickness on Cr(VI) activity and stability of photocatalytic reduction was studied by adjusting the content of PANI on Mesoporous TiO2(MT) surface.Under the irradiation conditions,the reaction results showed that the reduction rate was 100%,and the maximum reaction rate reached 0.62 min-1 when the PANI modification was 3.0%.Moreover,the results showed that the reduction performance remained 100% after ten cycles.The main reason is that the PANI modified on the surface of TiO2 is rich in positively charged amino group,which can efficiently adsorb the reactant Cr(VI),and make the product Cr(III) leave the reaction interface quickly,thus ensuring the performance of photocatalyst.展开更多
Developing anode catalysts of substantially enhanced activity for hydrogen oxidation reaction(HOR)and anti-CO poisoning performance is of great importance for the application of proton exchange membrane fuel cells(PEM...Developing anode catalysts of substantially enhanced activity for hydrogen oxidation reaction(HOR)and anti-CO poisoning performance is of great importance for the application of proton exchange membrane fuel cells(PEMFCs).Herein,we report Pd cluster in situ decorated urchin-like W_(18)O_(49)(WO_(2.72))electrocatalysts by a photo-reduction method for high performance HOR.The synthesized Pd-WO_(2.72)-L composite of low loading amount of 0.44 wt.%Pd by Xenon light reduction exhibits markedly high HOR catalytic activity and stability in 0.5 M H_(2)SO_(4),and the specific HOR current density and mass activity of Pd-WO_(2.72)-L are~1.5 and~80 times those of 20 wt.%Pt/C catalyst,respectively.Moreover,excellent anti-CO poisoning ability has also been obtained.The excellent HOR activity and anti-CO poisoning performance of Pd-WO_(2.72)-L have been discussed mainly in terms of the dual synergetic catalytic effects between Pd and WO_(2.72):Pd activation to Pd^(δ+)by the electron transfer from Pd to W promotes the hydrogen adsorption and activation to H*species,which results in largely elevated HOR activity;Pd degradation due to the CO poisoning is effectively prevented by WO_(2.72),which is responsible for the excellent CO-tolerance performance.展开更多
基金supported by Shandong Electric Power Construction Third Engineering Co.,Ltd.(20173702021476)the“HUIMN Science and Technology”project of Qingdao(17-3-3-71-nsh)+1 种基金the High-concentration Organic Wastewater Adsorbent Production Process(20170903)the National Natural Science Foundation of China(51602297,U1510109)。
文摘G-C3N4 was supported on the surface of foamed ceramic,and the g-C3N4@foamed ceramic was packed in the photocatalytic reactor in a layered manner.Effects of urea and H2O2 concentration on NO conversion were investigated.Pulse experiments were carried out to investigate the change of NO conversion with time under different concentrations of H2O2.The contribution of each route that NO converted and the selectivities of products were calculated.Results showed that the photo-reduction of NO accounted for 2%,and the photo-oxidation of NO accounted for 14%,and the rest was absorbed by the humidifier.Products include ammonia(NH+4-N),nitrogen(N2),nitrite(NO-2-N)and nitrate(NO-3-N),of which N2 accounted for 9%.
文摘In DMSO/water(4:1),photolysis of the dihydroxy-Sn(IV)-rnesoporphyrin dimethyl ester (SnP)/methyl viologen(MV^(2+))/ethylene diamine tetraacetic acid(EDTA)ternary system produces methyl viologen cation radical with a quantum yield of 0.67,much higher than that of systems with other metal complexes of rnesoporphyrin dimethyl ester.Neither EDTA nor MV^(2+) quenches the stationary fluorescence of SnP,implying that the reaction does not take place at the singlet state.With flash photolysis we obtain the T-T absorption spectrum of SnP(λ_(max)-440 nm).By following the decay of this absorption,the triplet life time of SnP is estimated to be 41 μs.The life time is related to the concentration of either MV^(2+) or EDTA.Good linear relationships are obtained by plotting τ_0/τ vs.the concentration of MV^(2+) or EDTA(Stern-Volmer plot),from which we determine the quenching constants:k_q(MV^(2+))=5.5×10~7 mol^(-7) s^(-1);kq(EDTA)=2.7×10~7 mol^(-1),s^(-1).The data suggests that upon photolysis of the above ternary system,both oxidative quenching and reductive quenching of the triplet state of the sensitizer are occurring.From the measured phosphorescence spectrum(λ_(max) 704nm)and the ground state redox potentials (E_(1/2)^(red)～-0.84V,E_(1/2)^(ox)～ Ag/AgCl,KCl(sat.)),we obtain the redox potential of triplet SnP to be E (P^+/P)～-0.33 V, E(P/P-)～+0.92 V.Matching this data with the redox potential of MV^(2+) and EDTA,we establish the fact that during the photolysis of the SnP/MV^(2+)/EDTA ternary system,both oxidative and reductive quenching are thermodynamically favorable processes.This is also the reason why the SnP sensitized reaction is much more efficient relative to other mesoporphyrin derivatives.
基金Supported by the National Natural Science Foundation of China(21676023,21376025)
文摘A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.
基金funded by the Chinese Academy of Engineering Consulting Project(No.2019-XZ-24)the National Key Re-search and Development Plans of Special Project for Site Soil(No.2018YFC1801002)。
文摘As a novel alternative to traditional perfluoroalkyl substances(PFASs),including perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),hexafluoroproplyene oxide trimer acid(HFPO-TA)has been detected worldwide in surface water.Moreover,recent researches have demonstrated that HFPO-TA has stronger bioaccumulation potential and higher hepatotoxicity than PFOA.To treat these contaminants e.g.PFOA and PFOS,some photochemical techniques by adding exogenous substances had been reported.However,there is still no report for the behavior of HFPO-TA itself under direct UV irradiation.The current study investigated the photo-transformation of HFPO-TA under UV irradiation in aqueous solution.After 72 hr photoreaction,75%degradation ratio and 25%defluorination ratio were achieved under ambient condition.Reducing active species,i.e.,hydrated electrons and active hydrogen atoms,generated from water splitting played dominant roles in degradation of HFPO-TA,which was confirmed by different effects of reaction atmospheres and quenching experiments.A possible degradation pathway was proposed based on the products identification and theoretical calculations.In general,HFPO-TA would be transformed into shorter-chain PFASs,including hexafluoropropylene oxide dimer acid(HFPODA),perfluoropropionic acid(PFA)and trifluoroacetate(TFA).This research provides basic information for HFPO-TA photodegradation process and is essential to develop novel remediation techniques for HFPO-TA and other alternatives with similar structures.
基金supported by the National Natural Science Foundation of China (22071246 and 22272178)CAS youth interdisciplinary team (JCTD-2022-12)+1 种基金CAS-Iranian Vice presidency for science and technology joint research project (121835KYSB20200034)China Postdoctoral Science Foundation (2023M733499)。
基金supported by the National Natural Science Foundation of China(21876114,21761142011,and 51572174)Shanghai Government(19160712900)+2 种基金International Joint Laboratory on Resource Chemistry(IJLRC),and Ministry of Education of China(PCSIRT_IRT_16R49)supported by The Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher LearningShuguang Research Program of Shanghai Education Committee.
文摘In order to develop efficient photocatalysts,great efforts have been made to reduce hexavalent chromium to trivalent chromium.The photocatalytic efficiency of this reduction depends largely on the adsorption and diffusion of hexavalent chromium ions on the surface of the photocatalyst.In this paper,polyanilineTiO2 composite can effectively improve the photocatalytic reduction performance and stability of hexavalent chromium ion.The effect of polyaniline(PANI) thickness on Cr(VI) activity and stability of photocatalytic reduction was studied by adjusting the content of PANI on Mesoporous TiO2(MT) surface.Under the irradiation conditions,the reaction results showed that the reduction rate was 100%,and the maximum reaction rate reached 0.62 min-1 when the PANI modification was 3.0%.Moreover,the results showed that the reduction performance remained 100% after ten cycles.The main reason is that the PANI modified on the surface of TiO2 is rich in positively charged amino group,which can efficiently adsorb the reactant Cr(VI),and make the product Cr(III) leave the reaction interface quickly,thus ensuring the performance of photocatalyst.
基金The authors gratefully acknowledged the support from the Natural Science Foundation of Shanghai(No.19ZR1479400)the State Key Laboratory for Modication of Chemical Fibers and Polymer Materials,Donghua University(No.KF1818)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology).
文摘Developing anode catalysts of substantially enhanced activity for hydrogen oxidation reaction(HOR)and anti-CO poisoning performance is of great importance for the application of proton exchange membrane fuel cells(PEMFCs).Herein,we report Pd cluster in situ decorated urchin-like W_(18)O_(49)(WO_(2.72))electrocatalysts by a photo-reduction method for high performance HOR.The synthesized Pd-WO_(2.72)-L composite of low loading amount of 0.44 wt.%Pd by Xenon light reduction exhibits markedly high HOR catalytic activity and stability in 0.5 M H_(2)SO_(4),and the specific HOR current density and mass activity of Pd-WO_(2.72)-L are~1.5 and~80 times those of 20 wt.%Pt/C catalyst,respectively.Moreover,excellent anti-CO poisoning ability has also been obtained.The excellent HOR activity and anti-CO poisoning performance of Pd-WO_(2.72)-L have been discussed mainly in terms of the dual synergetic catalytic effects between Pd and WO_(2.72):Pd activation to Pd^(δ+)by the electron transfer from Pd to W promotes the hydrogen adsorption and activation to H*species,which results in largely elevated HOR activity;Pd degradation due to the CO poisoning is effectively prevented by WO_(2.72),which is responsible for the excellent CO-tolerance performance.
