Under kinetic guidance, the stable metal‐organic framework PCN‐224 was synthesized and used as the parent MOF to embed Mn3+ to form PCN‐224(Mn). A molecule with two‐linked carboxyl groups and fluorine‐containing groups, which named 2,2′‐bis(trifluoromethyl)‐4,4′‐diphenyl phthalate (H2L), was also designed and synthesized. The PCN‐224(Mn) was then modified by introducing the H2L into its structure, forming a new hydrophobic porphyrinic MOF of PCN‐224(Mn)‐H2L. The catalytic oxidation performance of PCN‐224(Mn)‐H2L to cyclohexane was investigated. It was found that the hydrophobicity and stability of PCN‐224(Mn)‐H2L was improved markedly, and it had excellent catalytic performance with a selectivity to KA (mixture of cyclohexanone and cyclohexanol) of 90 %, a cyclohexane conversion rate of 51.3 % under mild reaction conditions, which far superior to that of PCN‐224(Mn) and the homogeneous metalloporphyrin catalysts. The catalyst remained stable after several repeated experiments.
Using pyrrole and terephthalaldehyde as raw materials, porphyrin-conjugated microporous polymer (CMP) without metal centers in the porphyrin ring was synthesized directly via the one-step method. The polymer was carbonized at different temperatures to obtain a series of carbonaceous nanospheres C-CMP-x (x is the pyrolysis temperature), of which C-CMP-900 is a multifunctional electrochemical catalyst with excellent performance. Compared to the uncarbonized polymer, C-CMP-900 is more sensitive and efficient for the reduction of nitrobenzene and exhibits a lower limit of detection. There was a significant improvement in the performance of nitrobenzene reduction over nonmetallic catalysts described in the literature. Moreover, the catalyst also shows excellent oxygen evolution reaction (OER) electrocatalytic activity, with lower overpotential than commercial RuO 2 . Even after long cycling tests, the catalyst maintained good activity. The catalyst, with an ultralow detection limit for nitrobenzene reduction and excellent OER activity, may be attributed to its high specific surface area and special porous carbon structure based on the porphyrin skeleton.
Magnetic composites containing anisotropic magnetic particles can achieve properties not possible in corresponding bulk or thin films of the magnetic material. In this work, we discuss how planar magnetic anisotropy may be achieved in a composite by aligning disk-shaped particles in an in-plane rotating magnetic field. Previous efforts have reported a simple model of aligning particles in a high-frequency rotating magnetic field. However, no complete analytic solution was proposed. Here, we provide a full analytic solution that describes the alignment dynamics of microdisks in a rotating field that covers the entire frequency range. We also provide simplified solutions at both high-frequency and low-frequency limits through asymptotic expansions for easy implementation into industrial settings. The analytic solution is confirmed by numerical simulation and shows agreement with experiments.
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