Metallopolymer Particle Engineering via Etching of Boronate Polymers toward High-Performance Overall Water Splitting Catalysts

Metallopolymers combine the property features of both metallic compounds and organic polymers, representing a typical direction for the design of high-performance hybrid materials. Here, a highly adaptive etching method to create pores and cavities in the metallopolymer particles is established. Starting from boronate polymer (BP) and inorganic@BP core-shell particles, porous, hollow, and yolk-shell metallopolymer particles can be fabricated, respectively. By taking advantage of the easy control over composition and pore/cavity structure, these metallopolymer particles provide a universal platform for the fabrication of nitrogen, boron co-doped carbon nanocomposites loaded with metals (M-NBCs). The as-prepared M-NBCs exhibit remarkable catalytic activities toward oxygen evolution reaction and hydrogen evolution reaction. An alkaline overall water splitting cell assembled by using M-NBCs as the anode and cathode can be driven by a single AAA battery. The proposed strategy for the construction of metallopolymer composites may enlighten for the design of complex hybrid nanomaterials.

Self-activatable carbon nanotube@ruthenium-catechol coordination complex for hydrogen evolution reaction

We report a simple metal ion-catechol coordination strategy to coat ruthenium-catechol polymer complex (TAC-Ru) on the surface of carbon nanotubes (CNT) to form a core-shell structure (abbreviated as CNT@TAC-Ru). This is achieved by firstly polymerizing catechol and boronic acid monomers on the surface of CNT to form a boronate ester polymer (BP) shell. Then, Ru³⁺is used to etch the BP shell, and cleave the dynamic boronate ester bond, leading to the formation of a CNT@ruthenium-catechol coordination complex based on the coordinative efficiency of the catechol group. The electrocatalytic property of the CNT@TAC-Ru composite can be activated through electrochemical cycling treatment. The as-activated CNT@TAC-Ru exhibits evidently improved hydrogen evolution reaction (HER) performance with an overpotential of 10 mV in 1.0 M KOH at a current density of 10 mA cm^-2, which is better than that of commercial Pt/C (32 mV). And the long-term stability is also desirable. This work provides a pyrolysis-free method to form metal-polymer-carbon composite with high HER performance under the alkaline condition.

A Facile Method for the Generation of Fe3C Nanoparticle and Fe-Nx Active Site in Carbon Matrix to Achieve Good Oxygen Reduction Reaction Electrochemical Performances

Introduction of both nitrogen and transition metal elements into the carbon materials has demonstrated to be a promising strategy to construct highly active electrode materials for energy shortage. In this work, through the coordination reaction between Fe³⁺ and 1,3,5-tris(4-aminophenyl)benzene, metallosupramolecular polymer precursors are designed for the preparation of carbon flakes co-doped with both Fe and N elements. The asprepared carbon flakes display wrinkled edges and comprise Fe₃C nanoparticle and active site of Fe-N_x. These carbon materials exhibit excellent electrocatalytic performance. Towards oxygen reduction reaction (ORR), the optimized sample has E_onset and E_half-wave of 0.93 V and 0.83 V in alkaline system, respectively, which are very close to that of Pt/C. This approach may offer a new way to high performance and lowcost electrochemical catalysts.

Morphology control and property design of boronate dynamic nanostructures

The morphogenesis of boronate dynamic nanostructures (BDNs) with different building blocks was systematically investigated to elucidate their design rules.

Concentration-directed morphological evolution of boronate ester-based dynamic covalent nanoparticles: a facile approach for size and shape control

Precursor concentrations dictated the formation processes of dynamic boronate nanoparticles, thus providing a facile route for morphological and size manipulation.

Covalent self-assembled nanoparticles with pH-dependent enhanced tumor retention and drug release for improving tumor therapeutic efficiency

Developing a smart drug delivery system with enhanced tumor retention at the tumor site, and rapid intracellular drug release promises to improve the therapeutic index and mitigate side effects. To this end, covalent phenylboronic acid (PBA)-based self-assembly nanoparticles (BNPs) consisting of pH-responsive cores and detachable poloxamer 188 shells were constructed for loading doxorubicin (DOX) in a simple process. The poloxamer 188 coating could be easily detached when the breakage of the borate ester bonds in the external nanocores was initially triggered in the tumor extracellular weak acid environment. The concealed PBA was subsequently exposed and could react with sialic acids (SA), which are overexpressed on tumor cells, and this enhanced the tumor retention effect of the fresh nanoparticle as well as facilitating the cellular uptake after removing the protective layers. Furthermore, owing to the existence of pH-responsive esters, the uptaken fresh nanoparticles could rapidly release DOX in the acidic tumor environment, which resulted in an enhanced therapeutic efficiency in vitro and in vivo. In summary, this pH dependent behaviour of DOX/BNPs provided new insights for enhanced chemotherapeutic treatment in cancer.

A general synthesis of abundant metal nanoparticles functionalized mesoporous graphitized carbon

A general coordination–polymerization strategy combining flexible coordination mode with stable polymer network is reported to construct metal–gallic acid resin and mesoporous graphitized carbon materials with abundant metal nanoparticles.

Synthesis of Five-Porphyrin Nanorings by Using Ferrocene and Corannulene Templates

The smallest and most strained member of a family of π-conjugated cyclic porphyrin oligomers was synthesized by using pentapyridyl templates based on ferrocene and corannulene. Both templates are effective for directing the synthesis of the butadiyne-linked cyclic pentamer, despite the fact that the radii of their N5 donor sets are too small by 0.5 Å and 0.9 Å, respectively (from DFT calculations). The five-porphyrin nanoring exhibits a structured absorption spectrum and its fluorescence extends to 1200 nm, reflecting strong π conjugation and Herzberg-Teller vibronic coupling.