Synthesis of TiO_2/g-C_3N_4 nanocomposites with phosphate–oxygen functional bridges for improved photocatalytic activity

One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface contact in the fabricated nanocomposite greatly influences the charge transfer and separation so as to determine the final photocatalytic activities.However,the role of interface contact is often neglected,and is rarely reported to date.Hence,it is possible to further enhance the photocatalytic activity of g‐C3N4‐based nanocomposite by improving the interfacial connection.Herein,phosphate-oxygen(P-O)bridged TiO2/g‐C3N4nanocomposites were successfully synthesized using a simple wet chemical method,and the effects of the P-O functional bridges on the photogenerated charge separation and photocatalytic activity for pollutant degradation and CO2reduction were investigated.The photocatalytic activity of g‐C3N4was greatly improved upon coupling with an appropriate amount of nanocrystalline TiO2,especially with P-O bridged TiO2.Atmosphere‐controlled steady‐state surface photovoltage spectroscopy and photoluminescence spectroscopy analyses revealed clearly the enhancement of photogenerated charge separation of g‐C3N4upon coupling with the P-O bridged TiO2,resulting from the built P-O bridges between TiO2and g‐C3N4so as to promote effective transfer of excited electrons from g‐C3N4to TiO2.This enhancement was responsible for the improved photoactivity of the P-O bridged TiO2/g‐C3N4nanocomposite,which exhibited three‐time photocatalytic activity enhancement for2,4‐dichlorophenol degradation and CO2reduction compared with bare g‐C3N4.Furthermore,radical‐trapping experiments revealed that the·OH species formed as hole‐modulated direct intermediates dominated the photocatalytic degradation of2,4‐dichlorophenol.This work provides a feasible strategy for the design and synthesis of high‐performance g‐C3N4‐based nanocomposite photocatalysts for pollutant degradation and CO2reduction.

Functional decoration on a regenerable bifunctional porous covalent organic framework probe for rapid detection and adsorption of copper ions

Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).

Drug delivery with Mn-doped MoO_(2) for photothermalenhanced chemotherapy in fighting cancers

Although chemotherapy has been intensively applied in cancer treatments,its inadequate therapeutic efficacy and severe side effects are still under constant concerns.Nanoplatforms used as anti-tumor drug delivery system(DDS)have attracted tremendous attentions owing to their various intriguing properties.Herein,Mn-doped MoO_(2)nanoparticles coated with ZrO_(2)and capped with Bi_(2)O_(3)have been designed as a DDS,namely MMZB.MMZB possesses good magnetic properties,great photothermal conversion ability,sensitive tumor microenvironment(TME)responsiveness,and good biocompatibility in hemocompatibility in vitro.Thus,MMZB has been utilized to load the chemotherapeutic agent daunomycin(DNM)(MMZB@DNM)for chemo-photothermal combined therapy.MMZB@DNM demonstrates a more impressive anti-cancer effect than the individual photothermal or chemotherapy both in vitro and in vivo.Furthermore,the analysis of tumor specimen sections and serum levels after the treatment indicates negligible side effects for MMZB@DNM in vivo.This contribution provides a valuable concept in designing therapeutic agents for achieving significantly enhanced tumor treatments,which benefits from the synergistic combination of chemotherapy and photothermal therapy in one single nanoagent.

Materials properties and device applications of semiconducting bismuth oxyselenide

Layered two-dimensional(2D)materials have garnered marvelous attention in diverse fields,including sensors,capacitors,nanocomposites and transistors,owing to their distinctive structural morphologies and superior physicochemical properties.Recently,layered quasi-2D materials,especially layered bismuth oxyselenide(Bi2O2Se),are of particular interest,because of their different interlayer interactions from other layered 2D materials.On this basis,this material offers richer and more intriguing physics,including high electron mobility,sizeable bandgap,and remarkable thermal and chemical durability,rendering it an utterly prospective contender for use in advanced electronic and optoelectronic applications.Herein,this article reviews the recent advances related with Bi2O2Se.Initially,its structural characterization,band structure,and basic properties are briefly introduced.Further,the synthetic strategies for the preparation of Bi_(2)O_(2)Se are presented.Furthermore,the diverse applications of Bi2O2Se in the field of electronics and optoelectronics,photocatalytic,solar cells and sensing were summarized in detail.Ultimately,the challenges and future perspectives of Bi2O2Se are included.

Prolonged lifetime and enhanced separation of photo- generated charges of nanosized α-Fe2O3 by coupling SnO2 for efficient visible-light photocatalysis to convert C02 and degrade acetaldehyde

To develop efficient visible-light photocatalysis on α-Fe2O3, it is highly desirable to promote visible-light-excited high-energy-level electron transfer to a proper energy platform thermodynamically. Herein, based on the transient-state surface photovoltage responses and the atmosphere-controlled steady-state surface photovoltage spectra, it is demonstrated that the lifetime and separation of photogenerated charges of nanosized α-Fe2O3 are increased after coupling a proper amount of nanocrystalline SnO2. This naturally leads to greatly improved photocatalytic activities for CO2 reduction and acetaldehyde degradation. It is suggested that the enhanced charge separation results from the electron transfer from α-Fe2O3 to SnO2, which acts as a proper energy platform. Based on the photocurrent action spectra, it is confirmed that the coupled SnO2 exhibits longer visible-light threshold wavelength （-590 nm） compared with the coupled TiO2 （-550 nm）, indicating that the energy platform introduced by SnO2 would accept more photogenerated electrons from α-Fe2O3. Moreover, electrochemical reduction experiments proved that the coupled SnO2 possesses better catalytic ability for reducing CO2 and O2. These are well responsible for the much efficient photocatalysis on SnO2-coupled α-Fe2O3.

FeNi@CNS nanocomposite as an efficient electrochemical catalyst for N_(2)-to-NH_(3) conversion under ambient conditions

The electrocatalytic nitrogen reduction reaction(NRR)has emerged as a promising renewable energy source and a feasible strategy as an alternative to Haber-Bosch ammonia(NH_(3))synthesis.However,finding an efficient and cost-effective robust catalyst to activate and cleave the extremely strong triple bond in nitrogen(N_(2))for electrocatalytic NRR is still a challenge.Herein,a FeNi@CNS nanocomposite as an efficient catalyst for N_(2) fixation under ambient conditions is designed.This FeNi@CNS nanocomposite was prepared by a simple water bath process and post-calcination.The FeNi@CNS is demonstrated to be a highly efficient NRR catalyst,which exhibits better NRR performance with exceptional Faradaic efficiency of 9.83%and an NH_(3) yield of 16.52μg h^(−1) cm^(−2) in 0.1 M Na_(2)SO_(4) aqueous solution.Besides,high stability and reproducibility with consecutive 6 cycles for two hours are also demonstrated throughout the NRR electrocatalytic process for 12 h.Meanwhile,the FeNi@CNS catalyst encourages N_(2) adsorption and activation as well as effectively suppressing competitive HER.Therefore,this earth-abundant FeNi@CNS catalyst with a subtle balance of activity and stability has excellent potential in NRR industrial applications.