Highly Selective Electrocatalytic CuEDTA Reduction by MoS_(2) Nanosheets for Efficient Pollutant Removal and Simultaneous Electric Power Output

Electrocatalytic reduction of ethylenediamine tetraacetic acid copper(CuEDTA),a typical refractory heavy metal complexation pollutant,is an environmental benign method that operates at mild condition.Unfortunately,the selective reduction of CuEDTA is still a big challenge in cathodic process.In this work,we report a MoS_(2) nanosheet/graphite felt(GF)cathode,which achieves an average Faraday efficiency of 29.6%and specific removal rate(SRR)of 0.042 mol/cm^(2)/h for CuEDTA at−0.65 V vs SCE(saturated calomel electrode),both of which are much higher than those of the commonly reported electrooxidation technology-based removal systems.Moreover,a proofof-concept CuEDTA/Zn battery with Zn anode and MoS_(2)/GF cathode is demonstrated,which has bifunctions of simultaneous CuEDTA removal and energy output.This is one of the pioneer studies on the electrocatalytic reduction of heavy metal complex and CuEDTA/Zn battery,which brings new insights in developing efficient electrocatalytic reduction system for pollution control and energy output.

Metal–Organic Framework-Based Sensors for Environmental Contaminant Sensing

Increasing demand for timely and accurate environmental pollution monitoring and control requires new sensing techniques with outstanding performance, i.e.,high sensitivity, high selectivity, and reliability. Metal–organic frameworks(MOFs), also known as porous coordination polymers, are a fascinating class of highly ordered crystalline coordination polymers formed by the coordination of metal ions/clusters and organic bridging linkers/ligands. Owing to their unique structures and properties,i.e., high surface area, tailorable pore size, high density of active sites, and high catalytic activity, various MOF-based sensing platforms have been reported for environmental contaminant detection including anions, heavy metal ions,organic compounds, and gases. In this review, recent progress in MOF-based environmental sensors is introduced with a focus on optical, electrochemical, and field-effect transistor sensors. The sensors have shown unique and promising performance in water and gas contaminant sensing. Moreover, by incorporation with other functional materials, MOF-based composites can greatly improve the sensor performance. The current limitations and future directions of MOF-based sensors are also discussed.

Environmental Analysis with 2D Transition-Metal Dichalcogenide-Based Field-Effect Transistors

Field-effect transistors(FETs)present highly sensitive,rapid,and in situ detection capability in chemical and biological analysis.Recently,two-dimensional(2D)transition-metal dichalcogenides(TMDCs)attract significant attention as FET channel due to their unique structures and outstanding properties.With the booming of studies on TMDC FETs,we aim to give a timely review on TMDCbased FET sensors for environmental analysis in different media.First,theoretical basics on TMDC and FET sensor are introduced.Then,recent advances of TMDC FET sensor for pollutant detection in gaseous and aqueous media are,respectively,discussed.At last,future perspectives and challenges in practical application and commercialization are given for TMDC FET sensors.This article provides an overview on TMDC sensors for a wide variety of analytes with an emphasize on the increasing demand of advanced sensing technologies in environmental analysis.

Fluorescence analysis of antibiotics and antibiotic-resistance genes in the environment: A mini review

Antibiotics,as widely used antibacterial drug,exist in various environmental media.Antibiotic residues can affect biological metabolism and lead to bacterial resistance and the formation of antibiotic-resistance genes,posing a threat to human health and ecological safety.Establishing efficient detection methods for antibiotics and antibiotic-resistance genes has great environmental significance.Fluorescence detection methods,due to their fast response,high sensitivity and specificity,and low-cost,are widely used in chemical and biological sensing.This review first summarizes the pre-treatment methods for different types of environmental samples,and then focuses on the recent advances of fluorescence methods for the detection of antibiotics and antibiotic-resistance genes.Finally,main challenges and future research directions of fluorescence methods for antibiotic and antibiotic-resistance genes detection are discussed.This review highlights the promising prospect of fluorescence methods in-situ detection and monitoring of antibiotics and antibiotic-resistance genes,and provides guidance for the construction of overall risk assessment system of environmental media.

Synergy of sodium doping and nitrogen defects in carbon nitride for promoted photocatalytic synthesis of hydrogen peroxide

Photocatalytic synthesis of hydrogen peroxide has gradually become a promising method for in-situ pro-duction of hydrogen peroxide,which relies on sustainable solar energy.However,the commonly used photocatalyst,i.e.,carbon nitride(CN),still suffers from the drawbacks of narrow light absorption range and fast charge recombination.Here,we report a facile method to introduce nitrogen defects into carbon nitride together with sodium ion.By adjusting the ratio of sodium dicyandiamide,the band gap of carbon nitride can be controlled,while the carrier separation and transfer ability of carbon nitride is improved.The modified CN with sodium doping and nitrogen defect(SD-CN)demonstrates outstanding H_(2)O_(2)pro-duction performance(H_(2)O_(2)yield rate of 297.2μmol L^(−1)h^(−1))under visible light irradiation,which is approximately 9.8 times higher than that of pristine CN.This work deepens the understanding of the coordinated effect of structural defect and element doping of carbon nitride on the photocatalytic H_(2)O_(2)production performance,and provides new insight into the design of photocatalytic system for efficient production of H_(2)O_(2).

ZnS-embedded porous carbon for peroxydisulfate activation:Enhanced electron transfer for bisphenol A degradation

Transition metal sulfides have garnered increasing attention for their role in persulfate activation,a crucial process in environmental remediation.However,the function of metal sulfides without reversible valence changes,such as ZnS,remains largely unexplored in this context.Here we report ZnS-embedded porous carbon(ZnS-C),synthesized through the pyrolysis of Zn-MOF-74 and dibenzyl disulfide.ZnS-C demonstrates remarkable activity in activating peroxydisulfate(PDS)across a wide pH range,enabling the efficient mineralization removal of bisphenol A(BPA).Through electrochemical investigation and theoretical simulations of charge density distributions,we unveil that the electron transfer from BPA to PDS mediated by the ZnS-C catalyst governs the reaction.This study,both in theory and experiment,demonstrates metal sulfide as electron pump that enhances electron transfer efficiency in PDS activation.These findings redefine the role of metal sulfide catalysts,shedding new light on their potential for regulating reaction pathways in PDS activation processes.

Modification strategies on 2D Ni-Fe MOF-based catalysts in peroxydisulfate activation for efficient organic pollutant removal

This study reports several modification strategies to optimize and enhance the performance of twodimensional(2D) metal organic frameworks(MOFs)-derived catalysts in peroxydisulfate(PDS) activation.The raw 2D Ni-MOF and 2D Ni-Fe-MOF without modification show poor catalytic activities for PDS activation and high metal ion leaching. The carbonization of 2D MOF can increase the activity of the catalyst but cannot solve the metal leaching problem. The further acid treatment of carbonization products can further improve the catalytic activity and decrease the metal ion leaching. The in-situ growth of2D MOF on graphene oxide(GO) support with subsequent carbonization and acid treatment offers the best performance in PDS activation for organic pollutant removal with low metal ion leaching. Compared with other PDS systems, the Ni-Fe-C-acid/GO system displays much lower catalyst and PDS dosages for p-chloroaniline degradation. This study presents new insights in the modification strategies of 2D MOFbased catalysts in PDS activation.

Facile,Noncovalent Decoration of Graphene Oxide Sheets with Nanocrystals

Facile dry decoration of graphene oxide sheets with aerosol Ag nanocrystals synthesized from an arc plasma source has been demonstrated using an electrostatic force directed assembly technique at room temperature.The Ag nanocrystal-graphene oxide hybrid structure was characterized by transmission electron microscopy(TEM)and selected area diffraction.The ripening of Ag nanocrystals on a graphene oxide sheet was studied by consecutive TEM imaging of the same region on a sample after heating in Ar at elevated temperatures of 100°C,200°C,and 300°C.The average size of Ag nanocrystals increased and the number density decreased after the annealing process.In particular,migration and coalescence of Ag nanocrystals were observed at a temperature as low as 100°C,suggesting a van der Waals interaction between the Ag nanocrystal and the graphene oxide sheet.The availability of affordable graphene-nanocrystal structures and their fundamental properties will open up new opportunities for nanoscience and nanotechnology and accelerate their applications.