Selective filtration of gas, water, and liquid or gaseous oil is essential to prevent possible environmental pollution and machine/facility malfunction in oil-based industries. Novel materials and structures able to selectively and efficiently filter liquid and vapor in various types of solutions are therefore in continuous demand. Here, we investigate selective gas-water-oil filtration using three-dimensional graphene structures. The proposed approach is based on the adjustable wettability of three-dimensional graphene foams. Three such structures are developed in this study; the first allows gas, oil, and water to pass, the second blocks water only, and the third is exclusively permeable to gas. In addition, the ability of three-dimensional graphene structures with a self-assembled monolayer to selectively filter oil is demonstrated. This methodology has numerous potential practical applications as gas, water, and/or oil filtration is an essential component of many industries.

A comprehensive method to prepare a one-dimensional (1D) metal−organic framework (MOF) has attracted research interest because the 1D MOFs are useful as precursor materials for the preparation of highly porous carbon nanorods with outstanding electrical conductivity and mechanical strength, making them particularly suitable for electrochemical applications. Herein, the synthesis of 1D zeolitic imidazolate framework-8 (ZIF-8) nanorods is reported using the metal-induced self-assembly templates of imidazole-functionalized perylenetetracarboxylic diimide (PDI-Hm). The size of PDI-Hm self-assemblies is finely tuned on the nanoscale by the method of metal-induced self-assembly whose surface-exposed metal ions were further exploited as nucleation sites for the growth of ZIF-8. Versatility of the metal-induced self-assembly template for the growth of other 1D MOFs was demonstrated using various transition-metal ions on demands. The size-controlled ZIF-8 nanorods were applied further as a precursor material to produce porous, nitrogen-doped carbon nanorods through the carbonization. The carbon nanorods show decent supercapacitor electrode material performance, with enhanced specific capacitance of 292.2 F g −1 , because of their unique 1D feature with reduced charge transfer resistance and large specific surface area derived from a downscaled template size under 100 nm.

In this study, we report self-assembled nitrogen-doped fullerenes (N-fullerene) as non-precious catalysts, which are active for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), and thus applicable for energy conversion and storage devices such as fuel cells and metal-air battery systems. We screen the best N-fullerene catalyst at the nitrogen doping level of 10 at%, not at the previously known doping level of 5 or 20 at% for graphene. We identify that the compressive surface strain induced by doped nitrogen plays a key role in the fine-tuning of catalytic activity.

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Summary Using first principles calculations, we study fundamental mechanism of spontaneous reduction reaction of Eu3+ to Eu2+ in eutectic LiCl‐KCl molten salt. We decouple the reaction Gibbs free energy into enthalpy and entropy contributions by using rigorous thermodynamic formalism. Key structural features of the solvation shell are characterized by the radial distribution function and the coordination number. Compared with Eu2+, the Eu3+ ion has a more rigid framework of the solvation shells, corroborating its stronger electrostatic interaction with neighboring ligands of Cl− ions and a more favorable state on the aspect of enthalpy. Computations on vibrational frequency, however, pose significant contribution of vibrational entropy to the reaction Gibbs free energy for the reduction. Vibration frequency of Eu2+ is smaller than that of Eu3+, driving a more positive change of the entropy in the reduction reaction. Furthermore, an Eu2+ diffuses more quickly than an Eu3+ in the LiCl‐KCl molten salt with switching mechanism of ligand Cl− ions in the solvation shell. Our results propose that the spontaneity of the reduction reaction is driven by the entropic contribution by overcoming the penalty of the reaction enthalpy.