No abstract

Environmentally benign, high-yield, cost-efficient, and facile fabrication of ultrathin two-dimensional (2D) nanomaterials has been a bottleneck restricting their massive and extensive applications. In this work, a one-step, solvent-free, and easily scalable approach for the preparation of WO3·2H2O ultrathin narrow nanosheets has been proposed for the first time, which is based on solid-state mechanochemical reaction between sodium tungstate dihydrate (Na2WO4·2H2O) and oxalate dihydrate (H2C2O4·2H2O) at ambient temperature. The resulting WO3·2H2O presents uniform rectangular nanosheets with a typical length of 50–80 nm, a width of about 10 nm, and a thickness of 5.67 nm. Phase evolution in the synthetic process of WO3·2H2O ultrathin narrow nanosheets was investigated by X-ray diffractometry. Their formation mechanism was also rationalized on the basis of in situ precipitation and preferential growth of ionized WO4 2– on the surface of mechanically exfoliated oxalate nanosheets. The WO3·2H2O ultrathin narrow nanosheets exhibit excellent adsorptive and UV-to-vis-light-driven photocatalytic properties with adequate recyclability in the removal of Rhodamine B (RhB) from aqueous solution, and also show promise for potential applications in photoelectronic devices, gas sensors, supercapacitors, lithium-ion batteries, and other environmental remediation.

No abstract

Large magnetostrain can be demonstrated in Ni-Mn-X (X = In, Sn, Sb) meta-magnetic shape memory alloys by resuming the predeformed martensite through magnetic-field-induced reverse martensitic transformation. However, owing to the constraint from the self-accommodated microstructure and randomly distributed crystallographic orientation, spontaneous magnetostrain without predeformation in polycrystalline alloys remains low. Here, by combining microstructure texturing and superelastic training, enhanced spontaneous magnetostrain was achieved in a directionally solidified Ni44.5Co4.9Mn37.5In13.1 alloy with strong <0 0 1>A preferred orientation. After superelastic training through cyclic compressive loading/unloading on the directionally solidified alloy, a large spontaneous magnetostrain of ~0.65% was obtained by applying a magnetic field of 5 T, showing great improvement when compared to that of the untrained situation, i.e., ~0.45%. Such enhanced magnetoresponse is attributed to the internal stress generated through superelastic training, which affects the variant distribution and the resultant output strain in association with the martensitic transformation.