An efficient mass transfer process is a critical factor for regulating catalytic activity in a photocatalytic desulfurization system.Herein,a phosphotungstic acid(HPW)active center is successfully composited with a qu...An efficient mass transfer process is a critical factor for regulating catalytic activity in a photocatalytic desulfurization system.Herein,a phosphotungstic acid(HPW)active center is successfully composited with a quaternary ammonium phosphotungstate-based hexadecyltrimethylammonium chloride ionic liquid(CTAC-HPW)by the ion exchange method for the photocatalytic oxidative desulfurization of dibenzothiophene sulfide.The keggin structure of HPW and highly mass transfer performance of organic cations synergistically enhanced the photocatalytic activity towards the effective convertion of dibenzothiophene(DBT)with the excitation of visible light.The deep desulfurization(<10 mg·kg^(-1))is attained within 30 min,and well stability is demonstrated within 25 cycles.Moreover,the CTAC-HPW photocatalyst projects well selectivity to interference from coexisting compounds such as olefins and aromatic hydrocarbons and universality of dibenzothiophenes,for example,4-methyldibenzothiophene(4-MDBT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT).Ultimately,a possible photocatalytic desulfurization mechanism is proposed according to the Gaschromatography-mass spectrometry(GC-MS),proving that the final product is the corresponding sulfone.The trapping experiment and electron spin resonance(ESR)analysis confirmed that h^(+)and,COOH played critical roles in the oxidation process.The work offers a practicable strategy for efficiently converting DBT to DBTO_(2) with added value.展开更多
With the bimodal mesoporous silica(BMMS)acting as the support and the composite of TiO2 with phosphotungstic acid(PTA)functioning as the active constituent,TiO_(2)-PTA/BMMS was synthesized by the two-step impregnation...With the bimodal mesoporous silica(BMMS)acting as the support and the composite of TiO2 with phosphotungstic acid(PTA)functioning as the active constituent,TiO_(2)-PTA/BMMS was synthesized by the two-step impregnation route.This catalyst was applied in the photocatalytic oxidative desulfurization(PODS)process,with dibenzothiophene serving as the model sulfur compound.PODS proceeds in one pot,in which H_(2)O_(2) acts as the oxidant and methanol plays the role of the solvent.TiO_(2)-PTA/BMMS was characterized by XRD,N_(2) adsorption and desorption,XRF,FTIR,UV-vis,SEM,EDS and TEM techniques.It showed that the introduction of PTA contributes higher order,higher surface area and pore volume to the bimodal mesoporous support.With TiO_(2)-PTA/BMMS used as the catalyst under the UV irradiation,the desulfurization rate can reach 99.6%.This result is obviously higher than that achieved by TiO_(2)/BMMS.The catalyst also has no significant drop in catalytic activity after eight runs of reusing.In such catalytic system,the synergistic effects of this photocatalytic oxidation and the extraction with the methanol serving as the solvent played an indispensable role.展开更多
Cerium fluoride(CeF_(3))semiconductor with upconversion property was constructed on graphite carbonitride(g-C_(3) N_(4))nanosheets by microwave hydrothermal method.The X-ray diffraction,transmission election microscop...Cerium fluoride(CeF_(3))semiconductor with upconversion property was constructed on graphite carbonitride(g-C_(3) N_(4))nanosheets by microwave hydrothermal method.The X-ray diffraction,transmission election microscopy,Fourier transform infrared,and X-ray photoelectron spectra techniques were used to characterize the CeF_(3)/g-C_(3)N_(4) nanocomposite.The study shows that CeF_(3) has upconversion property and can convert visible light(Vis)and near-infrared light(NIR)into ultraviolet light(UV).Mo reover,CeF3 and g-C_(3) N_(4) can form well-defined heterojunction and promote the effective separation of photogenerated electrons and holes.The synergistic effect of the CeF_(3)/g-C_(3)N_(4) nanocomposite was evaluated by photocatalytic degradation of dibenzothiophene(DBT).The optimum photocatalyst of CeF_(3)/g-C_(3)N_(4)(40 wt%)composites exhibit the highest photocatalytic desulfurization rate of the model oil under visible light radiation.展开更多
Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)ph...Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.展开更多
基金the financial supports from National Natural Science Foundation of China(22172066,22378176)supported by State Key Laboratory of Heavy Oil ProcessingSupported by Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment,Suzhou University of Science and Technology。
文摘An efficient mass transfer process is a critical factor for regulating catalytic activity in a photocatalytic desulfurization system.Herein,a phosphotungstic acid(HPW)active center is successfully composited with a quaternary ammonium phosphotungstate-based hexadecyltrimethylammonium chloride ionic liquid(CTAC-HPW)by the ion exchange method for the photocatalytic oxidative desulfurization of dibenzothiophene sulfide.The keggin structure of HPW and highly mass transfer performance of organic cations synergistically enhanced the photocatalytic activity towards the effective convertion of dibenzothiophene(DBT)with the excitation of visible light.The deep desulfurization(<10 mg·kg^(-1))is attained within 30 min,and well stability is demonstrated within 25 cycles.Moreover,the CTAC-HPW photocatalyst projects well selectivity to interference from coexisting compounds such as olefins and aromatic hydrocarbons and universality of dibenzothiophenes,for example,4-methyldibenzothiophene(4-MDBT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT).Ultimately,a possible photocatalytic desulfurization mechanism is proposed according to the Gaschromatography-mass spectrometry(GC-MS),proving that the final product is the corresponding sulfone.The trapping experiment and electron spin resonance(ESR)analysis confirmed that h^(+)and,COOH played critical roles in the oxidation process.The work offers a practicable strategy for efficiently converting DBT to DBTO_(2) with added value.
基金This work was supported by the Program for Liaoning Excellent Talents in Universities‘LNET’(LJQ2015062)the Program for Science and Technology Agency of Liaoning Province(20170540585)+1 种基金the General Scientific Research Project of Liaoning Provincial Department of Education(L2015296,L2016018)the Science and Technology Planning Project of Fushun(FSKJHT201376).
文摘With the bimodal mesoporous silica(BMMS)acting as the support and the composite of TiO2 with phosphotungstic acid(PTA)functioning as the active constituent,TiO_(2)-PTA/BMMS was synthesized by the two-step impregnation route.This catalyst was applied in the photocatalytic oxidative desulfurization(PODS)process,with dibenzothiophene serving as the model sulfur compound.PODS proceeds in one pot,in which H_(2)O_(2) acts as the oxidant and methanol plays the role of the solvent.TiO_(2)-PTA/BMMS was characterized by XRD,N_(2) adsorption and desorption,XRF,FTIR,UV-vis,SEM,EDS and TEM techniques.It showed that the introduction of PTA contributes higher order,higher surface area and pore volume to the bimodal mesoporous support.With TiO_(2)-PTA/BMMS used as the catalyst under the UV irradiation,the desulfurization rate can reach 99.6%.This result is obviously higher than that achieved by TiO_(2)/BMMS.The catalyst also has no significant drop in catalytic activity after eight runs of reusing.In such catalytic system,the synergistic effects of this photocatalytic oxidation and the extraction with the methanol serving as the solvent played an indispensable role.
基金supported by the National Natural Science Foundation of China(11774178,51801172)the Jiangsu Province Key Laboratory of Materials Surface Science and Technology and School-level Research Projects of Yancheng Institute of Technology(xjr2019026)。
文摘Cerium fluoride(CeF_(3))semiconductor with upconversion property was constructed on graphite carbonitride(g-C_(3) N_(4))nanosheets by microwave hydrothermal method.The X-ray diffraction,transmission election microscopy,Fourier transform infrared,and X-ray photoelectron spectra techniques were used to characterize the CeF_(3)/g-C_(3)N_(4) nanocomposite.The study shows that CeF_(3) has upconversion property and can convert visible light(Vis)and near-infrared light(NIR)into ultraviolet light(UV).Mo reover,CeF3 and g-C_(3) N_(4) can form well-defined heterojunction and promote the effective separation of photogenerated electrons and holes.The synergistic effect of the CeF_(3)/g-C_(3)N_(4) nanocomposite was evaluated by photocatalytic degradation of dibenzothiophene(DBT).The optimum photocatalyst of CeF_(3)/g-C_(3)N_(4)(40 wt%)composites exhibit the highest photocatalytic desulfurization rate of the model oil under visible light radiation.
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.21976054)Fundamental Research Funds for the Central Universities(No.FRFTP-20-005A3)。
文摘Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.