ChemNanoMat最新文献

Herein, we report the utilization of biochar derived from rice straw (RSB) as an effective support matrix for Pd nanoparticles and its application as an electrocatalyst for ethanol electro-oxidation (EEO) in an alkaline medium. Rice straw, a common agricultural byproduct, was pyrolyzed at 600 °C, 700 °C, and 800 °C under N₂ atmosphere. Pd was loaded onto the RSB via borohydride reduction of Pd²⁺, with a nominal loading of 20 % Pd. Spectroscopic and morphological characterization revealed the formation of dispersed Pd nanoparticles on the RSB surface. Pyrolysis temperature was observed to influence both the porosity of the resulting RSB and the dispersion and degree of exposure of Pd nanoparticles deposited on the surface. Electrochemical characterization revealed that Pd/RSB could be a potential EEO electrocatalyst for direct ethanol fuel cell applications. Pd/RSB-700 exhibited better performance in terms of EEO forward mass activity (j_f) and forward and backward mass activity (j_f/j_b) ratio relative to Pd/RSB-600 and Pd/RSB-800. Moreover, Pd/RSB was shown to be superior to commercial Pd on carbon black in terms of electrochemical stability. This study opens the potential of rice straw biochar as a sustainable and environmentally friendly carbon-based support matrix for Pd-based EEO electrocatalysts.

Gecko-like structures have been prepared by soft-template electropolymerization in micellar solution. Various monomers were designed from a triphenylamine core but only one monomer gives such structures even if the monomer is not perfectly planar. Extremely long and densely packed-microtubes are obtained at constant potential. However, the surfaces are not both highly hydrophobic and with strong water adhesion as gecko foot but are superhydrophilic. These differences can be explained by a higher surface energy or difference in arrangement structures for our surfaces. More information can be found in the Research Article by Thierry Darmanin and co-workers.

Stimuli-responsive color/fluorescence dual-switchable materials have garnered significant attention in displays, sensors, and anti-counterfeiting. However, current material systems are hampered by the single stimulus-response and unregulated fluorescence. Viologen derivatives featuring fluorophore as N-substituent and halogen anions as counteranions not only exhibit responsiveness to both electric and light stimuli but also enable adjustable emission. In this work, we explored the influence of halogen anions on the color/fluorescence dual-switching behaviors of 1,10-phenanthroline-based viologen derivatives. The energy level gaps for phen-Vio[2Cl⁻] (2.93 eV), phen-Vio[2Br⁻] (2.67 eV), and phen-Vio[2I⁻] (2.34 eV) decreased with the decrease of electron affinity of halogen anions (Cl⁻>Br⁻>I⁻), which leads to a sequential improvement in their electrochromic/electrofluorochromic and photochromic/photofluorochromic properties. This work has important guidance for the design and development of smart materials and their optoelectronic devices.

Manganese dioxide (MnO₂) nanoparticles are increasingly recognized for their potential in biomedical applications, particularly in the realm of hypoxic cancer therapy, due to their unique physicochemical characteristics. This investigation introduces a novel, template-free synthesis strategy. The reducing groups inherent in bovine serum albumin (BSA) facilitate a redox reaction with potassium permanganate (KMnO₄), while the abundance of functional groups in BSA is instrumental in the formation of MnO₂. The transmission electron microscopy (TEM) analysis has characterized the synthesized MnO₂ nanoparticles, termed BM NPs, as spherical particles with a mean diameter of 210 nm and zeta potential of −40.1 mV measured by dynamic light scattering (DLS). The Fourier transform infrared (FT-IR) spectrum of BM NPs exhibits the characteristic peak of MnO₂ at 1113 cm⁻¹ and 620 cm⁻¹_. Furthermore, the elemental composition of BM NPs has been ascertained through energy-dispersive X-ray (EDX) elemental mapping analysis. Though concentration of BM NPs up to 200 μg/mL, the survival rate of 4T1 cells remained approximately 75 %. Given that BM NPs at a concentration of 100 μg/mL significantly alleviate cellular hypoxia, the high oxygen-generating capacity of these nanoparticles is proved, suggesting their suitability as a drug delivery system, especially in the context of hypoxic tumor microenvironments.

The oral rifampicin (RIF) dosage forms possess various side effects and limited efficacy for tuberculosis treatment. Thus, this work developed the nano-in-microparticles containing RIF (trojan nRIF) as a novel pulmonary delivery system. The RIF-loaded nanoparticles (nRIF) were prepared by self-assembly polyelectrolyte complexation between lecithin and chitosan, whereas the trojan nRIF were formulated by spray-drying method of nRIF and mannitol/maltodextrin. The nRIF had a spherical shape with sizes of 86–126 nm, zeta potentials of 24–39 mV, entrapment efficiencies of 44–80 %, and drug loading capacities of 13–42 %. The RIF release from nRIF occurred in two stages, the initially rapid release stage and the controlled release stage upto 96 h, followed the Higuchi model. The trojan nRIF possessed the mass median aerodynamic diameter of 3.7–4.6 μm, fine particle fraction of 34–40 %, and alveolar fraction of 17–21 %. Compared to mannitol, maltodextrin was a superior carrier for nRIF, which yielded better aerodynamic properties and RIF was mainly stayed in the amorphous form. Moreover, using the scanning electron microscopy, the nano-in-microparticles were clearly observed with hollow structure. Finally, the trojan nRIF could preserve the physical properties of the encapsulated nRIF. In summary, the trojan nRIF could become a potential inhalation anti-tuberculosis product.

Two-dimensional Molybdenum diselenide is a versatile and promising material used for a wide range of applications and its synthesis in high quality and yield is currently the subject of intense research. Low temperature solution phase synthesis of nanomaterials using designed molecular precursors enjoys tremendous advantages over traditional high-temperature solid-state synthesis. However, molecular precursor chemistry of molybdenum selenide nanomaterials is almost non-existent. We report here synthesis and structural characterization of new molybdenum molecular precursors with selenoether and selenourea ligands, which due to their easy synthesis, desired Mo/Se composition and moderate processing properties, are highly promising as single source precursors for the scale-up production of 2D molybdenum diselenide materials. This is demonstrated by the solution-phase decomposition of the Mo-selenourea precursor which produced Mo-rich MoSe_2-x ultrathin nanosheets (NSs) in good yield. These NSs were characterized by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Powder X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies.

Developing transition metal based overall water splitting (OWS) electrocatalysts with high efficiency, low-cost, large current density, and long-term stability is crucial for industrial electrolysis of water, but remains a major challenge. In this study, a hierarchical electrocatalyst with MoS₂/Ni₃S₂ heterojunctions and a tiny amount of Au nanoparticles grown on nickel foam (MoS₂/Ni₃S₂-Au@NF) has been developed by a one-step hydrothermal method. The heterojunctions and Au nanoparticle decoration induce the electron-rich interfaces in the catalyst, which facilitate the synergistic adsorption of both OER and HER intermediates. As a result, MoS₂/Ni₃S₂-Au@NF possesses an excellent bifunctional electrocatalytic performance in 1 M KOH with low HER overpotential (78 mV@10 mA cm⁻², 253 mV@500 mA cm⁻²), low OER overpotential (261 mV@50 mA cm⁻², 435 mV@500 mA cm⁻²), and outstanding cyclical stability and continuous stability, which are superior than typical benchmarks of Pt/C and RuO₂. An electrolyzer assembled with the self-supported MoS₂/Ni₃S₂-Au@NF electrode also displays excellent OWS activity and stability with a current density beyond 100 mA cm⁻². This experiment is responding a potential alternative non-precious metal electrocatalyst for OWS at industrial settings, and thus promotes the real-world application of hydrogen energy conversions.