Three-dimensional hollow porous raspberry-like hierarchical Co/Ni@carbon microspheres for magnetic solid-phase extraction of pyrethroids

Bimetallic MOFs-Derived Hollow Carbon Spheres Assembled by Sheets for Sodium-Ion Batteries

Metal-organic frameworks (MOFs) have attracted extensive attention as precursors for the preparation of carbon-based materials due to their highly controllable composition, structure, and pore size distribution. However, there are few reports of MOFs using p-phenylenediamine (pPD) as the organic ligand. In this work, we report the preparation of a bimetallic MOF (CoCu-pPD) with pPD as the organic ligand, and its derived hollow carbon spheres (BMHCS). CoCu-pPD exhibits a hollow spherical structure assembled by nanosheets. BMHCS inherits the unique hollow spherical structure of CoCu-pPD, which also shows a large specific surface area and heteroatom doping. When using as the anode of sodium-ion batteries (SIBs), BMHCS exhibits excellent cycling stability (the capacity of 306 mA h g^-1 after 300 cycles at a current density of 1 A g^-1 and the capacity retention rate of 90%) and rate capability (the sodium storage capacity of 240 mA h g^-1 at 5 A g^-1). This work not only provides a strategy for the preparation of pPD-based bimetallic-MOFs, but also enhances the thermal stability of the pPD-based MOFs. In addition, this work also offers a new case for the morphology control of assembled carbon materials and has achieved excellent performance in the field of SIBs.

Designed new magnetic functional three-dimensional hierarchical flowerlike micro-nano structure of N-Co@C/NiCo-layered double oxides for highly efficient co-adsorption of multiple environmental pollutants

In order to eliminate multiple coexisting pollutants in environmental wastewater, a magnetic three-dimensional hierarchical porous flower-like N, Co-doped graphitic carbon nano-polyhedra decorated NiCo-layered double oxides (N-Co@C/NiCo-LDOs) adsorption material was synthesized, which consisted of two-dimensional LDOs nanosheets with functionalized surfaces (N, Co-doped graphitic carbon loaded on both sides of NiCo-LDOs nanosheets). The adsorption properties of N-Co@C/NiCo-LDOs for five types of typical pollutants (cationic dyes: rhodamine b, methylene blue; pesticides: ethofenprox, bifenthrin; anionic dyes: methyl orange, congo red; inorganic cations: Cr²⁺, Cd²⁺, Pb²⁺, Zn²⁺, inorganic anions: Cr₂O₇^2-, AsO₃^3-) were investigated systematically in single and coexisting systems. Combined with the results of FTIR and zeta potential, the adsorption mechanism was discussed. By virtue of its hierarchical porous architecture and the combined effect of functionalized surfaces and LODs supporter, the as-prepared N-Co@C/NiCo-LDOs demonstrates excellent adsorption performance towards five types of typical pollutants with fast adsorption rate, high adsorption capacity and good co-adsorption performance. More importantly, the N-Co@C/NiCo-LDOs showed satisfactory removal efficiency, stability and reusability in model wastewater. The broad-spectrum, rapid, easily separable, and reusable adsorption properties make N-Co@C/NiCo-LDOs promising for highly efficient wastewater treatments. This work also provides a feasible way for the preparation of adsorption materials for the treatment of complex wastewater systems.

3D flower-liked Fe3O4/C for highly sensitive magnetic dispersive solid-phase extraction of four trace non-steroidal anti-inflammatory drugs

A low cost-effective and simple synthesis method was adopted to acquire three-dimensional flower-like structure Fe₃O₄/C that has large specific area, suitable pore structure and sufficient saturation magnetism. The obtained Fe₃O₄/C exhibits outstanding preconcentration ability and was applied to extracting non-steroidal anti-inflammatory drugs from complex environmental and biological samples. The parameters of magnetic solid-phase extraction were optimized by univariate and multivariate methods (Box-Behnken design). The high degree of linearity from 2.5 to 1000.0 ng mL^-1 (R² ≥ 0.9976), the limits of detection from 0.25 to 0.5 ng mL^{- 1} (S/N = 3), and the limits of quantitation from 1.0 to 2.0 ng mL^{- 1} (S/N = 10) were yielded by adopting this novel method after the optimization. Moreover, the recoveries of non-steroidal anti-inflammatory drugs from 89.6 to 107.0% were acquired in spiked plasma, urine and lake samples. In addition, the adsorption of non-steroidal anti-inflammatory drugs on Fe₃O₄/C was explored by adsorption isotherms and kinetic studies. Furthermore, the adsorption mechanism for non-steroidal anti-inflammatory drugs by Fe₃O₄/C was proposed, which was hydrogen bonding and π-π interaction between non-steroidal anti-inflammatory drugs and Fe₃O₄/C. Graphical abstract.

Synthesis of Cobalt-Doped TiO2 Based on Metal-Organic Frameworks as an Effective Electron Transport Material in Perovskite Solar Cells

In this study, Co-doped TiO2 was prepared successfully using a solvothermal method with trimesic acid (H3BTC) as an organic framework to form the Co-doped Ti metal-organic framework (Co-doped Ti-MOF). By thermally decomposing the Co-doped Ti-MOF in air, the framework template was removed, and porous Co-doped TiO2 was obtained. The crystal structure of the material was analyzed using X-ray diffraction. The morphology was examined using scanning electron microscopy (SEM) and focused ion beam SEM. The large specific surface area was determined to be 135.95 m2 g-1 using Brunauer-Emmett-Teller theory. Fourier transform infrared spectroscopy verified the presence of Ti-O-Ti and Co-O vibrations in the as-prepared sample. Furthermore, the results of UV-vis spectroscopy showed that doping with Co remarkably improved the absorption ability of Ti-MOF toward the visible-light region with a band gap energy of 2.38 eV (λ = 502 nm). Steady-state photoluminescence and electrochemical impedance spectroscopy were conducted to illustrate the improvement of electron transfer in the doped material further. The optimum power conversion efficiency of solar cells using 1 wt % Co-doped TiO2 as an electron transport layer was found to be 15.75%, while that of solar cells using commercial dyesol TiO2 is only 14.42%.