In this work,a comparative study of three frequently employed modification techniques to g-C_(3)N_(4)(CN)nanosheets for the photocatalytic degradation of metribuzin(MET)under visible-light irradiation has been carried...In this work,a comparative study of three frequently employed modification techniques to g-C_(3)N_(4)(CN)nanosheets for the photocatalytic degradation of metribuzin(MET)under visible-light irradiation has been carried out in detail.The modification methods were coupling TiO_(2)nanoparticles(TO)as electron acceptors,nano-sized Fe_(2)O_(3)(FO)to construct a Z-scheme nanocomposite,and phosphate(HP)modification to promote O_(2)adsorption.The steady-state and transient-state surface photovoltage spectra and transient photoluminescence(PL)spectra confirmed that all the three modification techniques enhanced the charge separation with prolonged lifetimes and presented degradation activities in the order of TO/CN[FO/CN[HP/CN.The TO/CN nanocomposite showed the highest photocatalytic activity for MET degradation,with a sixfold higher rate than bulk CN.Liquid chromatography–tandem mass spectrometry and radical trapping experiments indicated that the increased activity was related to the synergetic effect of two radicals(·O^(2-) and ·OH)involved in the photocatalytic degradation pathway,which was different from the·OH radical-dominated pathway of bulk CN.This work reveals the importance of charge separation and the influence of the radical pathway and provides guidance for the design of high-efficiency photocatalysts.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21971057 and U1805255)the Natural Science Foundation of Heilongjiang Province(Nos.YQ2019B006 and LH2020B012)+2 种基金the Postdoctoral Research Foundation of Heilongjiang Province(No.LBH-Q19052)the Outstanding Youth Fund of Heilongjiang University(No.JCL201901)the Basic Scientific Research Expenses of Colleges and Universities in Heilongjiang Province(No.2020-KYYWF-1008).
文摘In this work,a comparative study of three frequently employed modification techniques to g-C_(3)N_(4)(CN)nanosheets for the photocatalytic degradation of metribuzin(MET)under visible-light irradiation has been carried out in detail.The modification methods were coupling TiO_(2)nanoparticles(TO)as electron acceptors,nano-sized Fe_(2)O_(3)(FO)to construct a Z-scheme nanocomposite,and phosphate(HP)modification to promote O_(2)adsorption.The steady-state and transient-state surface photovoltage spectra and transient photoluminescence(PL)spectra confirmed that all the three modification techniques enhanced the charge separation with prolonged lifetimes and presented degradation activities in the order of TO/CN[FO/CN[HP/CN.The TO/CN nanocomposite showed the highest photocatalytic activity for MET degradation,with a sixfold higher rate than bulk CN.Liquid chromatography–tandem mass spectrometry and radical trapping experiments indicated that the increased activity was related to the synergetic effect of two radicals(·O^(2-) and ·OH)involved in the photocatalytic degradation pathway,which was different from the·OH radical-dominated pathway of bulk CN.This work reveals the importance of charge separation and the influence of the radical pathway and provides guidance for the design of high-efficiency photocatalysts.
