Pseudocapacitive materials encapsulated in conductive carbon matrix are of paramount importance to develop energy storage devices with high performance and long lifespan. Here, via simple laser‐scribing, the Mn‐based metal–organic framework [EG‐MOF‐74(Mn)] is transformed into pseudocapacitive hybrid MnO/Mn7C3 encapsulated in highly conductive graphitic carbon. It is revealed that the rapid carbothermic reduction of MnO (C + MnO → C′ + Mn7C3 + CO) leads to the formation of the intermediate pseudocapacitive MnO/Mn7C3 and the concurrent catalytic graphitization of disordered carbon. This reaction produces a new type of pseudocapacitive material in the form of MnO/Mn7C3 fully embedded in highly conductive graphitic carbon. Thanks to the synergistic effect of the MnO/Mn7C3 nanoparticles and the graphitic carbon, the composite exhibits a high specific capacitance of 403 F g−1 with excellent stability. Asymmetric coin‐cell supercapacitors based on the composite demonstrate high energy (29.2 Wh kg−1) and power densities (8000 W kg−1) with a long lifespan. Prototypes of flexible paper‐based supercapacitors made of the composite also show great potential toward applications of flexible electronics.
Fluorescence-based assays should be feasible in aqueous media for effectively detecting the biological factors. However, numerous sensors have limited signal transductions and low fluorescence quantum yields due to the ingerently reduced excited state energy of fluorophores in aqueous solution, which reduces their sensitivity. This necessitates a smart sensing approach with an amplified fluorescence response for analytes in aqueous solution. Herein, a new building block which self-assembles in aqueous media, giving a micellar sturcuture with the hydrophobic π-extended conjugated system at the core and hydrophilic groups at the periphery, was devised for the first time. We demonstrated that the aggregated fluorophores in a micelle induce amplified fluorescence quenching, in which the excited electron efficiently migrates through π-extended conjugated system in a micelle, as in a polymeric system. Such feature differentiates this sensing approach from the numerous fluorescence-based tools previously developed for sensitive detection. This new system exhibited highly sensitive signal transduction for specific analytes even under actual bioanalytical conditions.
Due to their large surface areas and unique gas adsorption properties, mixed‐matrix membranes (MMMs) with metal–organic frameworks (MOFs) have been extensively studied in relation to various gas separations. In the present paper, we report the quick synthesis of MOF‐74 (M = Mg, Mn, Co, Ni) nanocrystals by microwave reactions and the fabrication of MMMs for use in CO2/N2 and O2/N2 separation. The scanning electron microscopy and energy dispersive X‐ray spectroscopy analysis revealed the homogenous distribution of the MOF‐74 nanocrystals within the polydimethylsiloxane (PDMS). The single gas permeation experiments showed the enhanced CO2/N2 and O2/N2 selectivity by adding the MOF‐74 nanocrystals to the PDMS. This enhanced CO2/N2 and O2/N2 selectivity may be due to the affinity of CO2 and O2 toward the Lewis acidic sites of the MOF‐74.
The design of nanostructured materials for efficient bifunctional electrocatalysts has gained tremendous attention, yet developing a fast and effective synthesis strategy remains a challenge. Here, we present a fast and...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.