The design of van der Waals heterojunctions with S-scheme charge transfer pathway is expected to be an effective strategy for improvement of photocatalytic performance.Herein,two-dimensional(2D)phosphorus-doped g-C_(3...The design of van der Waals heterojunctions with S-scheme charge transfer pathway is expected to be an effective strategy for improvement of photocatalytic performance.Herein,two-dimensional(2D)phosphorus-doped g-C_(3)N_(4)/Bi_(5)O_(7)Ivan der Waals heterojunctions with reduced graphene oxide as electron bridge(PCN/RGO/Bi_(5O)_(7)I)were successfully synthesized via hydrothermal method.The van der Waals interaction endowed 2D PCN/RGO/Bi_(5O)_(7)I with intimate contact interface,lattice match,tunable band structure,and internal electric field,which efficiently promoted interfacial charge separation and enhanced redox ability of photogenerated charge carriers.As a result,the S-scheme PCN/RGO/Bi_5O_7I van der Waals heterojunctions exhibited superior photocatalytic performance in ciprofloxacin degradation and real pharmaceutical wastewater treatment.The optimized 12%PCN/RGO/Bi_5O_7I displayed the highest photocatalytic activity with 92%removal of ciprofloxacin.Importantly,the COD removal efficiency and extent of mineralization of real pharmaceutical wastewater reached 66.9%and 59.8%,respectively,and the biodegradability of pharmaceutical wastewater was significantly improved.The photocatalytic mechanism of the S-scheme PCN/RGO/Bi_(5)O_(7)I van der Waals heterojunctions based on the analysis of reactive species,work function,and internal electric field was presented.This study provides fresh insights into plausible design of S-scheme van der Waals heterojunction to enhance photocatalytic redox ability.展开更多
The paper reports a novel amperometric biosensor for catechol based on immobilization of a highly sensitive horseradish peroxidase by affinity interactions on metal chelate-functionalized agarose/carbon nanotubes comp...The paper reports a novel amperometric biosensor for catechol based on immobilization of a highly sensitive horseradish peroxidase by affinity interactions on metal chelate-functionalized agarose/carbon nanotubes composites. Metal chelate affinity takes advantage of the affinity of Ni2＋ ions to bind strongly and reversibly to histidine or cysteine tails found on the surface of the horseradish peroxidase. Thus, enzymes with such residues in their molecules can be easily attached to functionalized aga- rose/carbon nanotubes composites support containing a nickel chelate. Linear sweep voltammograms and amperometry are used to study the proposed electrochemical biosensor. Catechol is determined by direct reduction of biocatalytically liberated quinone species at -0.05 V （vs. SCE）. The effect ofpH, applied electrode potential and the concentration of H2O2 on the sensitivity of the biosensor has been investigated. The performance of the proposed biosensor is tested using four different phenolic compounds, showing very high sensitivity, in particular, the linearity of cateehol is observed from 2.0 × 10-8 to 1.05×10-5 M with a detection limit of 5.0×10-9 M.展开更多
基金the National Natural Science Foundation of China(Grant Nos.51978324,51720105001,and 51962023)the Natural Science Foundation of Jiangxi Province(Grant Nos.20213BCJL22053,20192ACBL20043,and 20212BAB204045)+1 种基金the Department of Education Fund of Jiangxi Province(Grant No.GJJ210913)Graduate Innovation Fund(Grant No.YC2021-011)。
文摘The design of van der Waals heterojunctions with S-scheme charge transfer pathway is expected to be an effective strategy for improvement of photocatalytic performance.Herein,two-dimensional(2D)phosphorus-doped g-C_(3)N_(4)/Bi_(5)O_(7)Ivan der Waals heterojunctions with reduced graphene oxide as electron bridge(PCN/RGO/Bi_(5O)_(7)I)were successfully synthesized via hydrothermal method.The van der Waals interaction endowed 2D PCN/RGO/Bi_(5O)_(7)I with intimate contact interface,lattice match,tunable band structure,and internal electric field,which efficiently promoted interfacial charge separation and enhanced redox ability of photogenerated charge carriers.As a result,the S-scheme PCN/RGO/Bi_5O_7I van der Waals heterojunctions exhibited superior photocatalytic performance in ciprofloxacin degradation and real pharmaceutical wastewater treatment.The optimized 12%PCN/RGO/Bi_5O_7I displayed the highest photocatalytic activity with 92%removal of ciprofloxacin.Importantly,the COD removal efficiency and extent of mineralization of real pharmaceutical wastewater reached 66.9%and 59.8%,respectively,and the biodegradability of pharmaceutical wastewater was significantly improved.The photocatalytic mechanism of the S-scheme PCN/RGO/Bi_(5)O_(7)I van der Waals heterojunctions based on the analysis of reactive species,work function,and internal electric field was presented.This study provides fresh insights into plausible design of S-scheme van der Waals heterojunction to enhance photocatalytic redox ability.
基金supported by the National Outstanding Youth Foundations of China (50725825)National Basic Research Program of China (2007CB310501 & 2011CB935704)+2 种基金National Natural Science Foundation of China (50908113)the Natural Science Foundation of Jiangxi Province (2008GZH0008)the Youth Foundation of Jiangxi Provincial Department of Education (GJJ09483)
文摘The paper reports a novel amperometric biosensor for catechol based on immobilization of a highly sensitive horseradish peroxidase by affinity interactions on metal chelate-functionalized agarose/carbon nanotubes composites. Metal chelate affinity takes advantage of the affinity of Ni2＋ ions to bind strongly and reversibly to histidine or cysteine tails found on the surface of the horseradish peroxidase. Thus, enzymes with such residues in their molecules can be easily attached to functionalized aga- rose/carbon nanotubes composites support containing a nickel chelate. Linear sweep voltammograms and amperometry are used to study the proposed electrochemical biosensor. Catechol is determined by direct reduction of biocatalytically liberated quinone species at -0.05 V （vs. SCE）. The effect ofpH, applied electrode potential and the concentration of H2O2 on the sensitivity of the biosensor has been investigated. The performance of the proposed biosensor is tested using four different phenolic compounds, showing very high sensitivity, in particular, the linearity of cateehol is observed from 2.0 × 10-8 to 1.05×10-5 M with a detection limit of 5.0×10-9 M.
