N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial ...N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial Coulombic efficiency(ICE).In this study,high N-doped and low graphitic-N carbons(LGNCs)with enhanced ICE were synthesized by taking advantage of a denitrification strategy for graphitic carbon nitride(g-C_(3)N_(4)).In brief,more than 14.5 at%of N from g-C_(3)N_(4)(55.1 at%N)was retained by reacting graphitic-N with lithium,which was subsequently removed.As graphitic-N is largely responsible for the irreversible capacity,the anode's performance was significantly increased.Compared to general N-doped carbons with high graphitic-N proportion(>50%)and low N content(<15 at%),LGNCs delivered a low proportion of 10.8%-17.2% within the high N-doping content of 14.5-42.7 at%,leading to an enhanced specific capacity of 1499.9mAh g^(-1) at an ICE of 93.7% for the optimal sample of LGNC(4:1).This study provides a facile strategy to control the N content and speciation,achieving both high Li+storage capacity and high ICE,and thus promoting research and application of N-doped carbon materials.展开更多
Environmental endocrine disruptors,represented by bisphenol A(BPA),have been widely detected in the environment,bringing potential health risks to human beings.Nitrogen-containing biocarbon catalyst can activate perox...Environmental endocrine disruptors,represented by bisphenol A(BPA),have been widely detected in the environment,bringing potential health risks to human beings.Nitrogen-containing biocarbon catalyst can activate peroxymonosulfate(PMS)to degrade BPA in water,but its active sites remain opaque.Herein,in this work,nitrogen-containing biochar,i.e.,C–Nedge,enriched with graphitic-N defects at the edges was prepared by one-pot co-pyrolysis of chitosan and potassium carbonate.The results showed that the C–Nedge/PMS system can effectively degrade 98%of BPA(50 mg/L).The electron transfer based non-radical oxidation mechanism was responsible for BPA degradation.Edge graphitic-N doping endows biochar with strong electron transfer ability.The catalyst had good recovery and reuse performance.This catalytic oxidation was also feasible for other refractory pollutants removal and worked well for treating practical wastewater.This work may provide valuable information in unraveling the N doping configurationactivity relationship during activating PMS by biochar.展开更多
Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functiona...Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications.However,the photodegradation ability and corresponding structures of HPs are largely unknown,which hinder accurate estimation of the remediation effect of hydrochar in ecosystems.Herein,photodegradation performance of HP towards targeted norfloxacin(NOR,a typical antibiotic)under light irradiation(visible and UV light)were investigated after adsorption processes upon release into soil/water,and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar(BH)comprehensively.The results showed that:(1)photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light,in which reactive species of both HPs and BHs were·OH and·O2−;(2)density functional theory(DFT)results identified that the main photoactive structure of graphitic-N decreased the energy gap(Eg)of HPs,and C=O,COOH groups improved electron donating ability of BHs;(3)well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH.The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment.Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:51777138Deutsche Forschungsgemeinschaft(DFG,German Research Foundation),Grant/Award Number:491183248Open Access Publishing Fund of the University of Bayreuth。
文摘N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial Coulombic efficiency(ICE).In this study,high N-doped and low graphitic-N carbons(LGNCs)with enhanced ICE were synthesized by taking advantage of a denitrification strategy for graphitic carbon nitride(g-C_(3)N_(4)).In brief,more than 14.5 at%of N from g-C_(3)N_(4)(55.1 at%N)was retained by reacting graphitic-N with lithium,which was subsequently removed.As graphitic-N is largely responsible for the irreversible capacity,the anode's performance was significantly increased.Compared to general N-doped carbons with high graphitic-N proportion(>50%)and low N content(<15 at%),LGNCs delivered a low proportion of 10.8%-17.2% within the high N-doping content of 14.5-42.7 at%,leading to an enhanced specific capacity of 1499.9mAh g^(-1) at an ICE of 93.7% for the optimal sample of LGNC(4:1).This study provides a facile strategy to control the N content and speciation,achieving both high Li+storage capacity and high ICE,and thus promoting research and application of N-doped carbon materials.
基金National Natural Science Foundation of China(No.51908172)“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C03149)。
文摘Environmental endocrine disruptors,represented by bisphenol A(BPA),have been widely detected in the environment,bringing potential health risks to human beings.Nitrogen-containing biocarbon catalyst can activate peroxymonosulfate(PMS)to degrade BPA in water,but its active sites remain opaque.Herein,in this work,nitrogen-containing biochar,i.e.,C–Nedge,enriched with graphitic-N defects at the edges was prepared by one-pot co-pyrolysis of chitosan and potassium carbonate.The results showed that the C–Nedge/PMS system can effectively degrade 98%of BPA(50 mg/L).The electron transfer based non-radical oxidation mechanism was responsible for BPA degradation.Edge graphitic-N doping endows biochar with strong electron transfer ability.The catalyst had good recovery and reuse performance.This catalytic oxidation was also feasible for other refractory pollutants removal and worked well for treating practical wastewater.This work may provide valuable information in unraveling the N doping configurationactivity relationship during activating PMS by biochar.
基金supported by the National Natural Science Foundation of China(No.42207276)National Key Research and Development Program of China(2021YFD1700805).
文摘Hydrochar from waste biomass is a promising material for removing emerging contaminants(e.g.,antibiotics)in water/soil environment.Abundant small-sized hydrochar particles(HPs)with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications.However,the photodegradation ability and corresponding structures of HPs are largely unknown,which hinder accurate estimation of the remediation effect of hydrochar in ecosystems.Herein,photodegradation performance of HP towards targeted norfloxacin(NOR,a typical antibiotic)under light irradiation(visible and UV light)were investigated after adsorption processes upon release into soil/water,and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar(BH)comprehensively.The results showed that:(1)photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light,in which reactive species of both HPs and BHs were·OH and·O2−;(2)density functional theory(DFT)results identified that the main photoactive structure of graphitic-N decreased the energy gap(Eg)of HPs,and C=O,COOH groups improved electron donating ability of BHs;(3)well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH.The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment.Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance.
