The development of novel non-noble electrocatalysts is critical for an efficient electrochemical hydrogen evolution reaction (HER). In this study, high-density nickel-cobalt alloy nanoparticles embedded in the bent nitrogen-doped carbon nanosheets are prepared as a high-performance catalyst. The optimized Ni7Co3/NC-500 catalyst displays quite a low overpotential of 90 mV at a current density of 10 mA cm-2, and a small Tafel slope of 64 mV dec-1 in alkaline medium, and even performs better than commercial 20% Pt/C at a high current density (η150 = 233 mV for Ni7Co3/NC-500 and η150 = 267 mV for 20% Pt/C). Specifically, the high-density nickel-cobalt alloy (with an average size of 6.2 nm and a distance of <3.0 nm) embedded in the bent carbon nanosheets provides plentiful active sites. Furthermore, in situ visualization of the produced hydrogen bubbles shows that the small size of hydrogen bubbles (d = 0.2 mm for Ni7Co3/NC-500 vs. d = 0.8 mm for 20% Pt/C) resulting from the small water contact angle and the bent nanosheet structure would inhibit the aggregation of H2 bubbles on the surface to facilitate efficient mass diffusion. Density functional theory calculations reveal that the formation of the nickel-cobalt alloy can effectively lower water dissociation energy barriers and optimize hydrogen adsorption Gibbs free energy, manifesting a high HER activity.
Anticancer drugs such as biological therapeutic proteins and peptides are used for treatment of a variety of tumors. However, their wider use has been hindered by their poor bioavailability and the uncontrollable sites of action in vivo. Cancer nano-therapeutics is rapidly progressing, which is being applied for solving some limitations of conventional drug delivery systems. To improve the bio-distribution of anticancer drugs, carbon nanotubes have been used as one of the most effective drug carriers. This review discusses the carbon nanotubes-mediated methods for the delivery of anticancer drugs, with emphasis on the radiation-induced drug-targeted releasing and selective photo-thermal cancer therapy.
Si-based anode materials have attracted considerable attention because of their ultrahigh reversible capacity. However, poor cycling stability caused by the large volume change during cycling prevented the commercial application of Si anodes for lithium-ion batteries (LIBs). To overcome these challenges, in the present study, we designed a nitrogen plasma-treated core–bishell nanostructure where the Si nanoparticle was encapsulated into a SiOx shell and N-doped TiO2−δ shell. Here, the SiOx inside the shell and the TiO2 outside the shell act as binary buffer matrices to accommodate the large volume change and also help to stabilize the solid electrolyte interphase films on the shell surface. More importantly, the plasma-induced N-doped TiO2−δ shell with many Ti3+ species and oxygen vacancies plays a key role in improving the electrical conductivity of Si anodes. Owing to the synergistic effects of SiOx and N-doped TiO2−δ bishells, the cycling stability and rate performance of Si anodes are significantly enhanced. The as-obtained sample exhibits superior cycling stability with a capacity retention of 650 mA h g–1 at 200 mA g–1 after 300 cycles. This strategy is favorable for improving the electrochemical performances of Si-based anodes to employ in practical LIBs.
Here we report a hybrid of MnOx-CeO2/Ketjenblack as a novel catalyst for oxygen reduction reaction (ORR) by a facile strategy. This hybrid exhibits comparable activity and better stability towards ORR than the commercial 20 wt% Pt/C due to the synergistic effect.
In this paper, multi-walled carbon nanotubes (MWCNTs) were oxidized by 30 w% hydrogen peroxide to introduce hydroxyl groups and carboxyl groups on it. Catalyzed by p-toluenesulfonic acid, D-tartaric acid (DTA) was grafted onto MWCNTs by an esterification reaction. Fourier transform infrared spectroscopy and high resolution transmission electron microscopy were used to elucidate the introduced groups and the morphologies changes of the MWCNTs samples. The D-tartaric acid modified MWCNTs were used as chiral im pregnating reagents for thin-layer chromatography for enantioseparation of propranolol enantiomers, and the chiral separation factor was achieved over 7.23 by a mixed solvent of acetonitrile-tert-butanol-acetic acid (volume ratio is 49:49:2) as developing solvent. Keywords: Multi-walled carbon nanotubes, D-tartaric acid, functionalization, enantioseparation, thin-layer chromatography, propranolol.
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