This study aims to increase the photoactivity of ZnSnO_(3)by modifying it with zeolitic imidazolate framework-8(ZIF-8).The composite catalyst was prepared by a straightforward hydrothermal method using ZnSnO_(3)as the...This study aims to increase the photoactivity of ZnSnO_(3)by modifying it with zeolitic imidazolate framework-8(ZIF-8).The composite catalyst was prepared by a straightforward hydrothermal method using ZnSnO_(3)as the zinc source.The in-situ generated ZnSnO_(3)/ZIF-8 composite exhibits a strong interaction between ZnSnO_(3)and ZIF-8,which benefits electron transfer.Band structure analysis shows that ZIF-8 has a higher conduction band and a lower valence band than ZnSnO_(3),and cannot form a typical heterojunction.However,defects in ZIF-8 may act as electron traps,accepting electrons from the conduction band of ZnSnO_(3).This atypical heterojunction results in the spatial separation of charge carriers within the composite.The transient photocurrent response,electrochemical impedance spectroscopy,and photoluminescence analysis confirmed this hypothesis.Meanwhile,ZIF-8 also plays a role in adsorbing dyes and concentrating reactants due to its extremely high specific surface area.Therefore,the ZnSnO_(3)/ZIF-8 composite exhibits significantly improved photocatalytic performance in Rhodamine B degradation.The degradation rate of the best sample was 10.4 times that of ZnSnO_(3).Active species capture experiments showed that holes and superoxide radicals were the main active species.Additionally,the ZnSnO_(3)/ZIF-8 composite showed enhanced photocatalytic activity in CO_(2)reduction.This study may show new insights into the design of efficient photocatalytic materials using metal-organic framework materials.展开更多
用辉光放电电解等离子体(GDEP)对模拟染料废水罗丹明B(RhB)的降解过程进行了研究.通过发射光谱法测定了GDEP产生的活性粒子,采用紫外光谱分析了放电电压、溶液浓度、pH、Fe^(2+)等对RhB脱色率的影响,并用电导率仪和酸度计测定了降解过...用辉光放电电解等离子体(GDEP)对模拟染料废水罗丹明B(RhB)的降解过程进行了研究.通过发射光谱法测定了GDEP产生的活性粒子,采用紫外光谱分析了放电电压、溶液浓度、pH、Fe^(2+)等对RhB脱色率的影响,并用电导率仪和酸度计测定了降解过程中溶液的电导率和pH的变化,同时结合红外光谱粗略探讨了降解机理.结果表明,在最佳电压为600 V和放电60 min时,200 m L 20 mg·L^(-1)RhB的脱色率可达95.4%,降解过程符合动力学准一级反应;降解过程中溶液的电导率先增大后减小,溶液的pH呈现先减小后增大的趋势,说明在放电过程中产生了大量带电离子及酸性中间产物;加入0.03 mmol的Fe^(2+)对RhB的降解有催化作用,在pH=3.19条件下,放电5 min可使RhB的脱色率达到98.3%;羟基自由基(·OH)对RhB的降解起关键作用.展开更多
The prepared TiO2 suspension by sol-gel and hydrothermal method is spread on conducting glass substrates to prepare the photoelectrodes.The degradation of RhB at different bias under visible irradiation is researched....The prepared TiO2 suspension by sol-gel and hydrothermal method is spread on conducting glass substrates to prepare the photoelectrodes.The degradation of RhB at different bias under visible irradiation is researched.By the examination of UV-visible spectroscopy、degraded intermediates and removal yield of total organic carbon,the effect of bias on the photoelectrocatalytic degradation of RhB is investigated.It is found that N-dealkylation process predominates at positive bias(+0.6V vs SCE).Five N-de-ethylated intermediates are detected by HPLC.The removal yield of TOC is low,though dye RhB also discolors.But a rather facile cleavage of the whole conjugated chromophore structure of RhB at negative bias of-0.6 V vs SCE leads to the high mineralization yield.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22172144 and 22272151)the Public Welfare Technology Application Research Project of Jinhua City(No.2023-4-022)the Key Research and Development Program of Zhejiang Province(No.2023C03148).
文摘This study aims to increase the photoactivity of ZnSnO_(3)by modifying it with zeolitic imidazolate framework-8(ZIF-8).The composite catalyst was prepared by a straightforward hydrothermal method using ZnSnO_(3)as the zinc source.The in-situ generated ZnSnO_(3)/ZIF-8 composite exhibits a strong interaction between ZnSnO_(3)and ZIF-8,which benefits electron transfer.Band structure analysis shows that ZIF-8 has a higher conduction band and a lower valence band than ZnSnO_(3),and cannot form a typical heterojunction.However,defects in ZIF-8 may act as electron traps,accepting electrons from the conduction band of ZnSnO_(3).This atypical heterojunction results in the spatial separation of charge carriers within the composite.The transient photocurrent response,electrochemical impedance spectroscopy,and photoluminescence analysis confirmed this hypothesis.Meanwhile,ZIF-8 also plays a role in adsorbing dyes and concentrating reactants due to its extremely high specific surface area.Therefore,the ZnSnO_(3)/ZIF-8 composite exhibits significantly improved photocatalytic performance in Rhodamine B degradation.The degradation rate of the best sample was 10.4 times that of ZnSnO_(3).Active species capture experiments showed that holes and superoxide radicals were the main active species.Additionally,the ZnSnO_(3)/ZIF-8 composite showed enhanced photocatalytic activity in CO_(2)reduction.This study may show new insights into the design of efficient photocatalytic materials using metal-organic framework materials.
文摘用辉光放电电解等离子体(GDEP)对模拟染料废水罗丹明B(RhB)的降解过程进行了研究.通过发射光谱法测定了GDEP产生的活性粒子,采用紫外光谱分析了放电电压、溶液浓度、pH、Fe^(2+)等对RhB脱色率的影响,并用电导率仪和酸度计测定了降解过程中溶液的电导率和pH的变化,同时结合红外光谱粗略探讨了降解机理.结果表明,在最佳电压为600 V和放电60 min时,200 m L 20 mg·L^(-1)RhB的脱色率可达95.4%,降解过程符合动力学准一级反应;降解过程中溶液的电导率先增大后减小,溶液的pH呈现先减小后增大的趋势,说明在放电过程中产生了大量带电离子及酸性中间产物;加入0.03 mmol的Fe^(2+)对RhB的降解有催化作用,在pH=3.19条件下,放电5 min可使RhB的脱色率达到98.3%;羟基自由基(·OH)对RhB的降解起关键作用.
文摘The prepared TiO2 suspension by sol-gel and hydrothermal method is spread on conducting glass substrates to prepare the photoelectrodes.The degradation of RhB at different bias under visible irradiation is researched.By the examination of UV-visible spectroscopy、degraded intermediates and removal yield of total organic carbon,the effect of bias on the photoelectrocatalytic degradation of RhB is investigated.It is found that N-dealkylation process predominates at positive bias(+0.6V vs SCE).Five N-de-ethylated intermediates are detected by HPLC.The removal yield of TOC is low,though dye RhB also discolors.But a rather facile cleavage of the whole conjugated chromophore structure of RhB at negative bias of-0.6 V vs SCE leads to the high mineralization yield.
