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In anion exchange membrane fuel cells, catalytic reactions occur at a well‐defined three‐phase interface, wherein conventional heterogeneous catalyst layer structures exacerbate problems, such as low catalyst utilization and limited mass transfer. We developed a structural engineering strategy to immobilize a molecular catalyst tetrakis(4‐methoxyphenyl)porphyrin cobalt(II) (TMPPCo) on the side chains of an ionomer (polyfluorene, PF) to obtain a composite material (PF‐TMPPCo), thereby achieving a homogeneous catalysis environment inside ion‐flow channels, with greatly improved mass transfer and turnover frequency as a result of 100 % utilization of the catalyst molecules. The unique structure of the homogeneous catalysis system comprising interconnected nanoreactors exhibits advantages of low overpotential and high fuel‐cell power density. This strategy of reshaping of the catalyst layer structure may serve as a new platform for applications of many molecular catalysts in fuel cells. [ABSTRACT FROM AUTHOR]

Single- and double-walled WS2nanotubes of small diameter (<10 nm) and few layers (<4) have been synthesized by heating ultrathin W18O49nanowires and S powders in an H2/Ar atmosphere at 840°C. In the process of formation and growth of a WS2nanotube, the W18O49phase transformed first into an amorphous WS3structure via the absorption and diffusion of the sulfur atoms to substitute the oxygen atoms, and followed by a phase transition from amorphous WS3to 2H-WS2by losing sulfur atoms to form the shell of the WS2nanotube. IMPACT STATEMENT Synthesis of thin WS2nanotubes with single- and doubled-walled structure from ultrathin W18O49nanowires is developed and their structure and growth are studied using electron diffraction and microscopy. [ABSTRACT FROM AUTHOR]

In anion exchange membrane fuel cells, catalytic reactions occur at a well-defined three-phase interface, wherein conventional heterogeneous catalyst layer structures exacerbate problems, such as low catalyst utilization and limited mass transfer. We developed a structural engineering strategy to immobilize a molecular catalyst tetrakis(4-methoxyphenyl)porphyrin cobalt(II) (TMPPCo) on the side chains of an ionomer (polyfluorene, PF) to obtain a composite material (PF-TMPPCo), thereby achieving a homogeneous catalysis environment inside ion-flow channels, with greatly improved mass transfer and turnover frequency as a result of 100 % utilization of the catalyst molecules. The unique structure of the homogeneous catalysis system comprising interconnected nanoreactors exhibits advantages of low overpotential and high fuel-cell power density. This strategy of reshaping of the catalyst layer structure may serve as a new platform for applications of many molecular catalysts in fuel cells., (© 2020 Wiley-VCH GmbH.)

Dye-bearing wastewaters leading to the water pollution and ecological upset is a crucial issue in the textile industry. Herein, we report a facile method using two-dimensional transition metal carbides (MXenes) for the removal of the methylene blue (MB) in the water. The accordion-like V 2 CT x MXene is originally demonstrated to have high and spontaneous adsorption capacity of MB at 111.11 mg·g -1 , thrice over that of Ti 3 C 2 T x as previously reported. The wide lamellar space of V 2 CT x is certain to have large accommodation for MB. The electrostatic interaction effect and hydrogen bond between V 2 CT x and MB not only promote the efficient adsorption process but also provide the selectivity between anionic and cationic dyes. Combined with good reusability, we anticipate that the V 2 CT x MXene is a promising candidate for the removal of cationic dyes from textile-dye-bearing wastewaters.

We describe the structural parameters and atomic positions of a single-walled WS 2 nanotube. The structure factor is calculated in detail using analytic expressions for both single-walled and multi-walled WS 2 nanotubes. A zoning scheme has been developed to obtain the ratio m/n from the electron diffraction patterns. The procedure for determination of the chiral indices of both single-walled and multi-walled WS 2 nanotubes and the tilt angle is illustrated in detail for either normal incidence or inclined incidence. As an example of application, the determination of the chiral indices of a five-shell WS 2 nanotube was carried out and the tilt angle was obtained as 17.7°. The method developed here is useful and valid to determine the atomic structure of WS 2 nanotubes.