Bromine-based flow batteries receive wide attention in large-scale energy storage because of their attractive features, such as high energy density and low cost. However, the Br diffusion and relatively low activity of Br /Br hinder their further application. Herein, a cage-like porous carbon (CPC) with specific pore structure combining superhigh activity and Br -complex-entrapping capability is designed and fabricated. According to the results of density functional theory (DFT) calculation, the pore size of the CPC (1.1 nm) is well designed between the size of Br (4.83 Å), MEP (9.25 Å), and Br complex (MEPBr 12.40 Å), wherein Br is oxidized to Br , which forms a Br complex with the complexing agent immediately and is then entrapped in the cage via pore size exclusion. In addition, the active sites produced during the carbon dioxide activation process dramatically accelerate the reaction rate of Br /Br . In this way, combining a high Br -entrapping-capability and high specific surface areas, the CPC shows very impressive performance. The zinc bromine flow battery assembled with the prepared CPC shows a Coulombic efficiency of 98% and an energy efficiency of 81% at the current density of 80 mA cm , which are among the highest values ever reported.

Single-crystal beta-MnO(2) nanotubes with diameters in the range 200-500 nm and lengths up to several micrometers were successfully prepared by a simple hydrothermal method through oxidizing MnSO(4) with NaClO(3) in the presence of poly(vinyl pyrrolidone) (PVP). It was found that the formation process of beta-MnO(2) nanotubes included two primary evolution stages over time: (1) the MnOOH nanoparticles initially formed in the hydrothermal system and anisotropic growth to nanorods and nanorod aggregates, and (2) the MnOOH nanorods transformed into beta-MnO(2) tubular structure and grown into beta-MnO(2) nanotubes due to continuous growth through a dissolution-recrystallization process eventually. Based on a series of experimental analysis, the formation mechanism of these nanostructures was discussed briefly. The present study has enlarged the family of nanotubes available and offers a possible new, general route to one-dimensional single-crystalline nanotubes of other materials.

Photocatalytic hydrogen production has been considered a promising approach to obtain green hydrogen energy. Crystalline porous materials have arisen as key photocatalysts for efficient hydrogen production. Here, we report a strategy to in situ photodeposit platinum clusters as cocatalyst on a covalent organic framework, which makes it an efficient photocatalyst for light-driven hydrogen evolution. Periodically dispersed adsorption sites of platinum species are constructed by introducing adjacent hydroxyl group and imine-N in the region of the covalent organic framework structural unit where photogenerated electrons converge, leading to the in situ reduction of the adsorbed platinum species into metal clusters by photogenerated electrons. The widespread platinum clusters on the covalent organic framework expose large active surface and greatly facilitate the electron transfer, finally contributing to a high photocatalytic hydrogen evolution rate of 42432 μmol g−1 h−1 at 1 wt% platinum loading. This work provides a direction for structural design on covalent organic frameworks to precisely manipulate cocatalyst morphologies and positions at the atomic level for developing efficient photocatalysts.