Quick synthesis of CoFe-PBA@GO with electrochemical method as a novel, sensitive, and degradable nanocomposite applied in nanofibers for triazole extraction before HPLC-UV analysis

Today, the wide use of triazole fungicides due to environmental damage and its side effects has raised global concern. Hence, in this research, poly-vinyl alcohol/polyacrylic-acid/CoFe-PBA@GO electrospun nanofiber was synthesized and applied as effective, degradable, and novel adsorbent at pipette-tip microextraction (PT-μSPE) method for the rapid and concurrent extraction of five of triazole fungicides in fruit and vegetable samples prior to quantitative analysis by high-performance liquid chromatography-ultraviolet. The incorporation of CoFe-PBA@GO with superporous structure and abundant functional groups in a polymer medium improves the extraction efficiency of nanofibers due to hydrogen bonding and π-π interactions formed between analytes and synthesized nano-adsorbent. Various important elements that affect the extraction yield of the target analytes were optimized utilizing a time-variable approach. Under the optimum conditions, dynamic range was attained in the range of 0.3-900.0 ng/mL with correlation coefficients ≥ 0.999. The identification limit of the PT-μSPE-HPLC-UV method ranged from 0.1 to 0.3 ng/mL.

Well-defined bimetal oxides derived from Prussian blue analogues with regulable active sites for phosphate removal

Two well-defined CoFe bimetal oxides are prepared from Prussian blue analogues (PBAs) as precursors with designable structures, which are further explored for phosphate removal. A speed-controlled coordination strategy is used to fabricate two CoFe PBA microcrystals with different morphologies, then two regular CoFe oxides are obtained via an intermediate-temperature calcination. CoFeS, a slow-speed coordination product with truncated microcube structure, contains less coordinated water and Fe³⁺ in its framework, but can create more mesopores and Fe³⁺ in its oxidative product of CoFeST300. CoFeST300 has been demonstrated to have higher adsorption capacity and affinity for phosphate adsorption compared to that of the fast-speed coordination product, due to its more Fe³⁺ as effective adsorption sites via ligand exchange. Besides, the inner-sphere complexation mechanism makes CoFeST300 high selectivity for phosphate removal compared to other co-existing anions. The application performance of CoFeST300 is examined by multiple continuous treatment of actual sewage, and the result of all effluent concentrations below 0.5 mg P/L verifies a promising potential of the fabricated adsorbent for phosphorus removal. Thus, design or regulation of the precursors is an efficiency method to fabricate an ideal metal oxide for phosphate adsorption.

Cross-Linking and Charging Molecular Magnetoelectronics

Magnetoelectrics are witnessing an ever-growing success toward the voltage-controlled magnetism derived from inorganic materials. However, these inorganic materials have predominantly focused on the ferroelectromagnetism at solid-to-solid interfaces and suffered several drawbacks, including the interface-sensitive coupling mediators, high-power electric field, and limited chemical tunability. Here, we report a promising design strategy to shift the paradigm of next-generation molecular magnetoelectrics, which relies on the integration between molecular magnetism and electric conductivity though an in situ cross-linking strategy. Following this approach, we demonstrate a versatile and efficient synthesis of flexible molecular-based magnetoelectronics by cross-linking of magnetic coordination networks that incorporate conducting chain building blocks. The as-grown compounds feature an improved critical temperature up to 337 K and a room-temperature magnetism control of low-power electric field. It is envisaged that the cross-linking of molecular interfaces is a feasible method to couple and modulate magnetism and electron conducting systems.

Achieved RGBY Four Colors Changeable Electrochromic Pixel by Coelectrodeposition of Iron Hexacyanoferrate and Molybdate Hexacyanoferrate

Although multicolor electrochromic materials and devices have been studied by many researchers, there is still none an inorganic single-layer film that has red, blue, and green three typical color states, while red, green, and blue (RGB) are indispensably for multicolor display. Iron hexacyanoferrate (FeHCF) is a kind of well-studied inorganic electrochromic material with relatively colorful properties and a great family of analogues. In this Research Article, the RGBY film with red, green, blue and yellow four typical color states are obtained successfully by coelectrodeposition of FeHCF and molybdate hexacyanoferrate (MoOHCF). This film contains the electrochromic properties of both components. Moreover, benefiting from its high A⁺ (alkali cation ions that can insert/extract into/from the framework, such as Li⁺ and K⁺) content, the redox process of RGBY film can be fully completed to achieve rich color variation. The absorptivity adjustment range of RGBY film at 730 and 440 nm are 0.81 and 0.43, respectively. The response time of RGBY films varies from 3 to 30 s between states and maintains its optical properties without significant decay during 1000 cycles. Finally, a pixelated electrode and a facile electrochromic device based on RGBY film have been developed to exhibit its high application potential in nonemission display field.

Coordinating gallium hexacyanocobaltate: Prussian blue-based nanomaterial for Li-ion storage

Prussian blue analogs (PBAs) are a type of metal–organic framework and have drawn significant attention recently. To date, most are constructed with divalent transition metal ions coordinated to the N end of a cyanide bridge. In this report, we studied a trivalent gallium ion-based Ga hexacyanocobaltate (GaHCCo), which depicted a face-centered cubic crystal structure. In addition, the synthesized GaHCCo was demonstrated as a cathode material of lithium-ion batteries (LIBs) and was found to exhibit long-term stability, having a capacity retention of 75% after 3000 cycles of repeated charge–discharge cycling and an extremely high coulombic efficiency of 98%, which was achieved because of a solid-state diffusion controlled Li-ion storage process. After ex situ XRD analysis on the different charge stages, the Li-ion storage in the GaHCCo was attributed to the Co species via the formation of a Li/Co compound. This work will pave the way toward the study of PBAs constructed with trivalent metal ions and provide more insights into the development of high-performance LIBs in the future.

A newfound Prussian blue analog, gallium hexacyanocobaltate, has been demonstrated as an electrode material for Li-ion storage.

Bimetal Prussian Blue as a Continuously Variable Platform for Investigating the Composition-Activity Relationship of Phosphides-Based Electrocatalysts for Water Oxidation

Doping unary transition-metal phosphides (TMPs) by secondary metal is a powerful method to improve their catalytic activity for electrochemical oxygen evolution reaction (OER). However, the composition-activity relationship of such doping has not been systematically investigated yet because of the challenge in constructing bimetal TMPs with continuously variable composition while keeping homogenous elemental distribution. Herein, we develop a strategy of using bimetal Prussian blue analogues with homogenous elemental distribution at molecular scale as an ideal platform to achieve bimetal cobalt-iron phosphides (Co_{1- x}Fe _xP) with a continuously changeable Co/Fe ratio (0 < x < 1) and uniform metal distribution. Such a system allows us to draw out a composition-activity volcano profile of Co_{1- x}Fe _xP for OER. By optimizing the composition, the best catalytic activity is obtained at the Co/Fe ratio of 1.63 in Co_{1- x}Fe _xP with small overpotentials of 230 and 268 mV at 10 and 100 mA cm^-2, respectively, which outperform most of the reported TMPs. These results may inspire the use of multicomponent molecular platforms to understand composition-dependent performance and explore highly efficient catalysts for diverse applications.

Synthesis of CoFe Prussian blue analogue/poly vinylidene fluoride nanocomposite material with improved thermal stability and ferroelectric properties

Synthesis of a nanocomposite CoFe Prussian blue analogue (CoFePBA) molecular magnet with a polyvinylidene fluoride (PVDF) polymer show improved thermal stability and ferroelectric properties.