Porous Pt Nanotubes with High Methanol Oxidation Electrocatalytic Activity Based on Original Bamboo-Shaped Te Nanotubes

In this report, a facile and general strategy was developed to synthesize original bamboo-shaped Te nanotubes (NTs) with well-controlled size and morphology. On the basis of the as-prepared Te NTs, porous Pt nanotubes (NTs) with excellent property and structural stability have been designed and manufactured. Importantly, we avoided the use of surface stabilizing agents, which may affect the catalytic properties during the templated synthesis process. Furthermore, Pt NTs with different morphology were successfully prepared by tuning the experimental parameters. As a result, transmission electron microscopy (TEM) study shows that both Te NTs and Pt NTs have uniform size and morphology. Following cyclic voltammogram (CV) testing, the as-prepared porous Pt NTs and macroporous Pt NTs exhibited excellent catalytic activities toward electrochemical methanol oxidation reactions due to their tubiform structure with nanoporous framework. Thus, the as-prepared Pt NTs with specific porous structure hold potential usage as alternative anode catalysts for direct methanol fuel cells (DMFCs)

Sub-10 nm Sr₂LuF₇:Yb/Er@Sr₂GdF₇@SrF₂ Up-Conversion Nanocrystals for Up-Conversion Luminescence–Magnetic Resonance–Computed Tomography Trimodal Bioimaging

Herein, sub-10 nm core–shell nanocrystals (NCs), which select Sr₂LuF₇:Yb/Er as core, Sr₂GdF₇ as middle shell, and SrF₂ as an outermost shell, were synthesized by a seed-mediated growth process. The NCs possess good crystallinity, morphology, and up-conversion luminescent properties. After modification by polyethylenimine branched (PEI), in vitro cell up-conversion imaging with low autofluorescence was realized. Due to the presence of Gd³⁺ ions, in vivo magnetic resonance (MR) imaging was also achieved with these designed NCs. More significantly, these special core–shell NCs exhibited high contrast in in vivo X-ray computed tomography (CT) imaging because of their good X-ray absorption ability. These results indicate that the core–shell up-conversion NCs can serve as promising contrast agents for up-conversion luminescence–MR–CT trimodal bioimaging

Application of Cu₃InSnSe₅ Heteronanostructures as Counter Electrodes for Dye-Sensitized Solar Cells

In this research, we reported the synthesis of quaternary Cu₃InSnSe₅ nanoparticles with uniform size distribution and morphology for the first time through delicate controls over the chemical reaction kinetics. On the basis of the preparation strategy of Cu₃InSnSe₅ nanoparticles, Pt–Cu₃InSnSe₅ and Au–Cu₃InSnSe₅ heteronanostructures were designed and yielded using a simple and efficient seed growth method. These two heteronanostructures remained monodispersed without presence of any Cu₃InSnSe₅ nanocrystal impurities. To explore their application potentials for dye-sensitized solar cells, counter electrodes consisting of individual Cu₃InSnSe₅, Pt–Cu₃InSnSe₅, or Au–Cu₃InSnSe₅ constituents were fabricated. Current density–voltage (<i>J</i>–<i>V</i>) characteristics evaluation reveals that Cu₃InSnSe₅ nanoparticles, Pt–Cu₃InSnSe₅ and Au–Cu₃InSnSe₅ heterostructured nanoparticles display a comparative power conversion efficiency (PCE) of 5.8%, 7.6%, and 6.5% to that of a Pt-based counter electrode (7.9%), respectively. As such, we believe that the reported preparation strategy could provide new insights to the design and manufacture of counter electrode materials with controlled structure, morphology, and optimized power conversion efficiency for dye-sensitized solar cells