The g-MoS2 coated biochar(g-MoS2-BC)composites were synthesized by coating original biochar with g-MoS2 nanosheets at 300℃(BC300)/700℃(BC700).The adsorption properties of the g-MoS2-BC composites for ciprofloxacin(C...The g-MoS2 coated biochar(g-MoS2-BC)composites were synthesized by coating original biochar with g-MoS2 nanosheets at 300℃(BC300)/700℃(BC700).The adsorption properties of the g-MoS2-BC composites for ciprofloxacin(CIP)were investigated with an aim to exploit its high efficiency toward soil amendment.The specific surface area and the pore structures of biochar coated g-MoS2 nanosheets were significantly increased.The g-MoS2-BC composites provided more n electrons,which was favorable in enhancing the n-n electron donor-acceptor(EDA)interactions between CIP and biochar.As a result,the g-MoS2-BC composites showed faster adsorption rate and greater adsorption capacity for CIP than the original biochar.The coated g-MoS2 nanosheets contributed more to CIP adsorption on the g-MoS2-BC composites due to their greater CIP adsorption capacity than the original biochar.Moreover,the synergistic effect was observed for CIP adsorption on g-MoS2-BC700,and suppression effect on g-MoS2-BC300.In addition,the adsorption of CIP onto g-MoS2-BC composites also exhibited strong dependence on the solution pH,since it can affect both the adsorbent surface charge and the speciation of contaminants.It was reasonably suggested that the mechanisms of CIP adsoiption on g-MoS2-BC composites involved pore-filling effects,k-k EDA interaction,electrostatic interaction,and ion exchange interaction.These results are useful for the modification of biochar in exploiting the novel amendment for contaminated soils.展开更多
Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐di...Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2018YFC1800704)the National Natural Science Foundation of China(No.21577124).
文摘The g-MoS2 coated biochar(g-MoS2-BC)composites were synthesized by coating original biochar with g-MoS2 nanosheets at 300℃(BC300)/700℃(BC700).The adsorption properties of the g-MoS2-BC composites for ciprofloxacin(CIP)were investigated with an aim to exploit its high efficiency toward soil amendment.The specific surface area and the pore structures of biochar coated g-MoS2 nanosheets were significantly increased.The g-MoS2-BC composites provided more n electrons,which was favorable in enhancing the n-n electron donor-acceptor(EDA)interactions between CIP and biochar.As a result,the g-MoS2-BC composites showed faster adsorption rate and greater adsorption capacity for CIP than the original biochar.The coated g-MoS2 nanosheets contributed more to CIP adsorption on the g-MoS2-BC composites due to their greater CIP adsorption capacity than the original biochar.Moreover,the synergistic effect was observed for CIP adsorption on g-MoS2-BC700,and suppression effect on g-MoS2-BC300.In addition,the adsorption of CIP onto g-MoS2-BC composites also exhibited strong dependence on the solution pH,since it can affect both the adsorbent surface charge and the speciation of contaminants.It was reasonably suggested that the mechanisms of CIP adsoiption on g-MoS2-BC composites involved pore-filling effects,k-k EDA interaction,electrostatic interaction,and ion exchange interaction.These results are useful for the modification of biochar in exploiting the novel amendment for contaminated soils.
基金supported by National Natural Science Foundation of China(51672113)Six Talent Peaks Project in Jiangsu Province(2015-XCL-026)+3 种基金Natural Science Foundation of Jiangsu Province(BK20171299)State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-KF201705),Fuzhou UniversityState Key Laboratory of Advanced Technology for Materials Synthesis and Processing(2016-KF-10),Wuhan University of Technologythe Qing Lan Project Foundation of Jiangsu Province~~
文摘Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.
