Facile Transformation of Imine Linkages and Functionalization of Aldehyde in the Covalent Organic Frameworks for Stable and Enhanced Photocatalytic Hydrogen Peroxide Production.

Imine-based covalent organic frameworks (COFs) have been widely applied in photocatalytic hydrogen peroxide (HO) production because of their highly crystalline properties and tunable chemical structures. However, the inherent polarization of C═N linkage brings a high energy barrier for π-electron delocalization, impeding the in-plane photoelectron transfer process, which leads to an inadequate efficiency of HO photosynthesis. In addition, the chemical stability of most imine-COFs remains insufficient due to the reversible nature of imine linkage.

Dual Regulation of Charge Separation and the Oxygen Reduction Pathway by Encapsulating Phosphotungstic Acid into the Cationic Covalent Organic Framework for Efficient Photocatalytic Hydrogen Peroxide Production.

Previous research on covalent organic framework (COF)-based photocatalytic HO synthesis from oxygen reduction focuses more on charge carrier separation but less on the electron utilization efficiency of O. Herein, we put forward a facile approach to simultaneously promote charge separation and tailor the oxygen reduction pathway by introducing phosphotungstic acid (PTA) into the cationic COF skeleton. Experiments verified that PTA, as an electron transport medium, establishes a fast electron transfer channel from the COF semiconductor conductor band to the substrate O; meanwhile, the reaction path is optimized by its catalytic cycle for preferable dioxygen capture and reduction in oxygen reduction reaction (ORR) kinetics.

Strengthened Fenton degradation of phenol catalyzed by core/shell Fe-Pd@C nanocomposites derived from mechanochemically synthesized Fe-Metal organic frameworks.

We have prepared core/shell structured hollow Fe-Pd@C nanomaterials derived from Fe-metal organic frameworks which were synthesized via cheap, fast and simple mechanochemical technique. The obtained Fe-Pd@C can steadily and continuously release Fe from the galvanic corrosion of Fe anode to trigger HO decomposition into hydroxyl radicals and cause fast (10 min) and efficient (mineralization rate 95%) degradation of phenol. The presence of low level of Pd NPs in Fe-Pd@C (mass ratio of the raw material: Fe/Pd = 100:1) facilitated fast Fe/Fe redox cycle and thus improved the catalytic performance and pH endurance of the Fe-Pd@C.

Ball milling synthesis of covalent organic framework as a highly active photocatalyst for degradation of organic contaminants.

Facile, environmentally-friendly fabrication of high-yield and stable covalent organic framework (COF) materials has been a limitation to their large-scale production and application. In this work, ball milling was used to synthesize COF by mechanochemical reaction between 1,3,5-triformylphloroglucinol (Tp) and melamine (MA) at ambient temperature. Different routes (liquid-free, solvent-assisted and catalyst-assisted) and proportions of liquids (solvents or catalyst) were investigated.

Construction of a superior visible-light-driven photocatalyst based on a CN active centre-photoelectron shift platform-electron withdrawing unit triadic structure covalent organic framework.

Herein, three functional factors inducing photocatalytic ability were artfully integrated into a covalent organic framework (COF), where triazine units served as photoactive centers, cyclic ketone units served as electron-withdrawing moieties, and the conjugated structure served as a photoelectron shift platform. This COF with segregated donor-acceptor alignments exhibits an excellent visible-light photocatalytic capacity for the decomposition of organic pollutants.

Facile Synthesis of Magnetic Covalent Organic Framework with Three-Dimensional Bouquet-Like Structure for Enhanced Extraction of Organic Targets.

A facile strategy for the fabrication of novel bouquet-shaped magnetic porous nanocomposite via grafting a covalent organic framework (COF, TpPa-1) onto the surface-modified FeO nanoparticles (FeO NPs) was reported. The magnetic TpPa-1 (a COF synthesized from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1)) contains clusters of core-shell magnetic nanoparticles and interconnected porous TpPa-1 nanofibers. Thus, it possesses larger specific surface area, higher porosity, and supermagnetism, making it an ideal sorbent for enrichment of trace analytes.

One-step synthesis of potassium ferricyanide-doped polyaniline nanoparticles for label-free immunosensor.

A novel, label-free and inherent electroactive redox immunosensor for ultrasensitive detection of carcinoembryonic antigen (CEA) was proposed based on gold nanoparticles (AuNPs) and potassium ferricyanide-doped polyaniline (FC-PANI) nanoparticles. FC-PANI composite was synthesized via oxidative polymerization of aniline, using potassium ferricyanide (K3[Fe(CN)6]) as both oxidant and dopant. FC-PANI acting as the signal indicator was first fixed on a gold electrode (GE) to be the signal layer.

Direct electron transfer of glucose oxidase and biosensing for glucose based on PDDA-capped gold nanoparticle modified graphene/multi-walled carbon nanotubes electrode.

In this work, poly (diallyldimethylammonium chloride) (PDDA)-capped gold nanoparticles (AuNPs) functionalized graphene (G)/multi-walled carbon nanotubes (MWCNTs) nanocomposites were fabricated. Based on the electrostatic attraction, the G/MWCNTs hybrid material can be decorated with AuNPs uniformly and densely. The new hierarchical nanostructure can provide a larger surface area and a more favorable microenvironment for electron transfer.