Various layered materials, including hexagonal boron nitride (h-BN), graphite, and molybdenum disulfide (MoS2), have been successfully exfoliated to be cationic two-dimensional (2D) materials for the first time. The raw layered materials were exfoliated by a ball milling method with polycation solution as the medium, which can effectively stabilize the layered materials in the solution, mitigate the large ball momentum to destroy the layered materials, impede the oxidation of the layered materials, and functionalize the obtained 2D materials. These advantages lead to the preparation of various cationic 2D materials, such as h-BN, graphene, and MoS2, with high yield, good quality, and good solution processability. The prepared cationic 2D materials were heteroassembled with anionic ones because of the electrostatic interactions between them, showing much better performance than that obtained when using one single component alone. By using the 2D h-BN/rGO as a photocatalyst, the dye decomposed by 95% after 7 min of light illumination, which was much more efficient than using the rGO (54%) and 2D h-BN (38%) alone. By using the titania nanosheets/ball milled graphene composites as the anode for the sodium-ion battery application, the capacity was 353 mA h g–1 at a cycling speed of 100 mA g–1, ∼6 folds of pure titania nanosheets. This facile method to synthesize various cationic 2D materials may open up a new avenue to fabricate 2D heterostructures and study their properties.

The catalysts used to decrease the overpotential for this reaction play a pivotal role in realizing these devices. [2] Currently, iridium (Ir) and ruthenium (Ru) based oxides have been used as efficient OER catalysts. However, the scarcity and price of these materials makes them unsuitable for large-scale applications such that they need to be replaced with low-cost nonprecious metal electrocatalysts. [3] Many transition metal-based materials are promising alternatives to promote OER in alkaline media. Among the earth-abundant elements, cobalt was found to be one of the best alternatives to replace noble metals for OER. Cobalt derivatives are widely investigated as OER catalysts, including their oxides, [4] nitrides, [5,6] selenides, [7] borides, [8] carbides, [9] and phosphides. [10] The surfaces of these materials are known to undergo in situ transformations at Co sites to form cobalt oxyhydroxide (CoOOH) under the electric potential applied during the water oxidation process. [11] This surface reconstruction process directly determines the final performance of the catalysts. For instance, Duan et al., reported the controllable anodic leaching of Cr in CoCr 2 O 4 by activating the pristine material at high potential, which enables the transformation of the inactive CoCr 2 O 4 spinel into a highly Here, the synthesis of a series of pure phase metal borides is reported, including WB, CoB, WCoB, and W 2 CoB 2 , and their surface reconstruction is studied under the electrochemical activation in alkaline solution. A cyclic voltammetric activation is found to enhance the activity of the CoB and W 2 CoB 2 precatalysts due to the transformation of their surfaces into the amorphous CoOOH layer with a thickness of 3-4 nm. However, such surface transformation does not happen on the WB and WCoB due to their superior structure stability under the applied voltage, highlighting the importance of metal components for the surface reconstruction process. It is found that, compared with CoB, the W 2 CoB 2 surface shows a quicker reconstruction with a larger active surface area due to the selective leaching of the W from its surface. In the meantime, the metallic W 2 CoB 2 core underneath the CoOOH layer shows a better promotion of its oxygen evolution reaction (OER) performance than CoB. Therefore, the ternary W 2 CoB 2 shows better OER performance than the CoB, as well as the WB and WCoB. It is also found that the mixture of W 2 CoB 2 with Pt/C as the catalysts in air electrode for rechargeable Zn-air battery (ZAB), shows better performance than the IrO 2 -Pt/C couple-based ZAB.

Metallic lithium (Li) is a highly promising anode for high-energy-density batteries. However, irreversible Li deposition and Li dendrite growth during cycling, originated from unstable interface and chemistry disintegration, are the...

1D inorganic nanomaterials have been synthesized, which have been widely used for various applications, such as energy storage and conversion, bioelectronics, and electronic/optoelectronic devices. [6][7][8][9] Noteworthy, the smaller the diameter, the more fantastic properties 1D nanomaterials may have. [10] For instance, the semiconducting single-walled carbon nanotubes with a diameter of 0.8-1.6 nm have been taken as promising channel materials for nextgeneration transistors. [11] A tungsten oxide nanowire with a diameter of <1 nm showed a much better photochemical reduction of CO 2 than the commercial tungsten oxides due to the large surface area. [12] So far, the species with a diameter of <5 nm were still limited to a few inorganic materials, which are synthesized by specific conditions, such as chemical vapor deposition for the controlled synthesis of single-walled carbon nanotubes and solvothermal method to prepare metal oxide nanowires. [13][14][15][16] Methods that can prepare other types of ultrathin 1D nanomaterials on large scale are necessary for the expansion of their application fields.Polymers are well-developed for over a century and are prepared by polymerizing functional monomers with catalyticThe growth of ultrathin 1D inorganic nanomaterials with controlled diameters remains challenging by current synthetic approaches. A polymer chain templated method is developed to synthesize ultrathin Bi 2 O 2 CO 3 nanotubes. This formation of nanotubes is a consequence of registry between the electrostatic absorption of functional groups on polymer template and the growth habit of Bi 2 O 2 CO 3 . The bulk bismuth precursor is broken into nanoparticles and anchored onto the polymer chain periodically. These nanoparticles react with the functional groups and gradually evolve into Bi 2 O 2 CO 3 nanotubes along the chain. 5.0 and 3.0 nm tubes with narrow diameter deviation are synthesized by using branched polyethyleneimine and polyvinylpyrrolidone as the templates, respectively. Such Bi 2 O 2 CO 3 nanotubes show a decent lithium-ion storage capacity of around 600 mA h g −1 at 0.1 A g −1 after 500 cycles, higher than other reported bismuth oxide anode materials. More interestingly, the Bi materials developed herein still show decent capacity at very low temperatures, that is, around 330 mA h g −1 (−22 °C) and 170 mA h g −1 (−35 °C) after 75 cycles at 0.1 A g −1 , demonstrating their promising potential for practical application in extreme conditions.