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Heterointerface tailoring is of importance for the catalytic activity enhancement of nanomaterials in various reactions owing to the charge polarization at the interface. We report an accurate manipulation of a replacement reaction for Pt/PtTe heteronanowire and PtTe homonanowire fabrication. Their geometric structures are controlled by using the aged K2PtCl4 in ethylene glycol (EG) as Pt precursors with self-tuned coordination state and structure. The aging process enables the slow conversion of PtCl42– to linear structured PtmCln leading to their tunable oxidation ability. The Pt–Pt bond formation during aging has been revealed by time-resolved in situ UV–vis and X-ray absorption fine structure (XAFS) spectroscopies. The coexistence of a highly active Te template, PtCl42– ions, and linear structured PtmCln complexes allows Pt nanoparticles (NPs) to grow in situ on the PtTe nanowires (NWs), forming a controllable interface structure that served as catalytic active sites and charge transfer location. In c...

Formic acid oxidation is an important electrocatalytic reaction in protonexchange membrane (PEM) fuel cells, in which both active sites and species adsorption/activation play key roles. In this study, we have developed hollow Pd-Ag alloy nanostructures with high active surface areas for application to electrocatalytic formic acid oxidation. When a certain amount of Ag is incorporated into a Pd lattice, which is already a highly active material for formic acid oxidation, the electrocatalytic activity can be significantly boosted. As indicated by theoretical simulations, coupling between Pd and Ag induces polarization charges on Pd catalytic sites, which can enhance the adsorption of HCOO* species. As a result, the designed electrocatalysts can achieve reduced Pd usage and enhanced catalytic properties at the same time. This study represents an approach that simultaneously fabricates hollow structures to increase the number of active sites and utilizes interatomic interactions to tune species adsorption/activation towards improved electrocatalytic performance.

Self-assembly/disassembly is ubiquitous in nature and plays an important role in many biological events. But noninvasive characterization of this process in real time at molecular resolution remains challenging. Herein, using homebuilt liquid-phase scanning tunneling microscopy (L-STM) with ultrahigh stability, we directly visualized enzymatic self-assembly/disassembly of oligopeptide nanofibers in real time for the first time. Static high-resolution L-STM images clearly showed the molecular packing details in the supramolecular nanofiber and the diameter of the nanofiber was consistent with that of cryo transmission electron microscopy (cryo-TEM) observations. Moreover, the self-repairing behavior of the supramolecular nanofibers was also directly observed at high resolution for the first time. This work unprecedentedly revealed new insights into Nature-mimic self-assembly and disassembly at the molecular level. It also illustrates the potential of our homebuilt L-STM in studying delicate biological processes in physiological solution with high resolution.

As for the problem that the non-stationary fluctuating wind induces dramatic changes of atmosphere refraction at tens of meters height above the rough ocean surface, which reduces the accuracy of orbit measurement and control system while tracking spacecraft at low elevation. A new atmosphere refraction modification method is investigated based on the modified Monin-Obukhov approximation, with the consideration of the influence by random rough ocean surface which is established by Monte-Carlo method. Experimental results of several in-orbit spacecraft measurement data indicate that precision can be dramatically improved compared with traditional methods.

Polymer hydrogels and small-molecule-based (SMB) supramolecular hydrogels have been widely explored. But oligomeric hydrogels have remained a challenge because synthetic difficulties of the oligomers and control of their amphiphilicities. Reported herein is the rational design of two precursors Cys(SEt)-Lys-CBT (1) and (Cys-Lys-CBT)2 (2) (CBT=2-cyano-6-aminobenzothiazole) and the use of a biocompatible condensation to prepare oligomeric hydrogels. Glutathione reduction of 1 or 2 yields the same gelator Cys-Lys-CBT (3) which condenses with each other to yield amphiphilic cyclic oligomers. The oligomers instantly self-assemble into nanofibers and form oligomeric hydrogels with similar mechanic properties. Chemical analyses indicated that the major condensation product in both two hydrogels is a cyclic dimer. Considering its biocompatibility, optimal mechanical strength, and biodegradability, we believe that our oligomeric hydrogel might be useful for long-term drug delivery in the future.

Spontaneously precise organization of small structures into complex superstructures is ubiquitous and important in nature. But using small building blocks to mimic this process remains a challenge to scientists. Herein, we report the rational design of a bipyridine-derivative and applied it for the self-assembly of nanorings. The addition of Fe(2+) to the nanorings resulted in the assembly of the nanorings into supernanostructures via Fe(2+)-bipyridine coordination. HPLC, HR-ESI/MS, UV-vis, DLS, and TEM analyses clearly validated the intramolecular cyclization, self-assembly of the nanorings, and the additional self-assembly of the superstructures via Fe(2+)-bipyridine coordination. We envision our strategy to be a new approach of precisely assembling nanostructures of ring shape into more complex superstructures.

Employing cellular environment for the self-assembly of supramolecular nanofibers for biological applications has been widely explored. But using one precursor to differentiate the extra- and intracellular environments to self-assemble into two different nanofibers remains challenging. With the knowledge that the extracellualr environment of some cancer cells contains large amounts of alkaline phosphatase (ALP) while their intracellular environment is glutathione (GSH)-abundant in mind, we rationally designed a precursor Cys(SEt)-Glu-Tyr(H2PO3)-Phe-Phe-Gly-CBT (1) that can efficiently yield amphiphilic 2 and 2-D to self-assemble into two different nanofibers in hydrogels under the sequential treatment of ALP and GSH. We envision that, by employing a click condensation reaction, this work offers a platform for facilely postmodulation of supramolecular nanofibers, and the versatile precursor 1 could be used to kill two birds with one stone.

Two-dimensional g-C3N4 nanosheets with few-layer thickness, ensuring equivalent charge migrations to various Pd facets, provide an ideal model system for reliably examining the facet selectivity of Pd co-catalysts. It reveals that reduction of CO2 can occur better on Pd{111} facets while H2O prefers to generate H2 on Pd{100}.