Electroreduction of dioxygen for fuel-cell applications: materials and challenges. High-performance electrocatalysts for oxygen reduction derived from polyaniline, iron, and cobalt. Electrocatalyst approaches and challenges for automotive fuel cells. A class of non-precious metal composite catalysts for fuel cells. What are batteries, fuel cells, and supercapacitors? Chem Rev, 2004, 104: 4245–4270īashyam R, Zelenay P. The present work provides a facile strategy for preparing single atom catalysts in bulk quantity and contributes to development of catalysts for electrochemical conversion and storage devices. Moreover, it also displays high catalytic activity for oxygen evolution reaction (OER), suggesting it is an efficient ORR/OER bifunctional catalyst. Benefiting from strong stabilization of Co atoms on CTF, Co CTF/KB shows outstanding stability with only 5 mV negative shifts after 10,000 cycles. The prepared single Co catalyst (Co-CTF/KB) possesses high metal loading over 4 wt% and shows superior ORR performance with a half-wave potential ( E 1/2) of 0.830 V and a limiting current density of 6.14 mA cm −2 as well as high tolerance of methanol in an alkaline medium, which outperforms commercial Pt/C and most non precious metal catalysts reported to date. Here, we prepared a highly active and stable atomically isolated cobalt catalyst via covalent triazine framework (CTF) support with Ketjen Black (KB) hybridization in scale. However, it is still a great challenge to develop a cost-effective, ultrastable and efficent single-atom cobalt catalyst for ORR, requiring efficient fabrication strategies and robust support to stabilize the single cobalt atom. Therefore, TPS-Co may have potential applications in bone regeneration.Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction (ORR). Proliferation assay of MC3T3-E1 cells demonstrated that TPS-Co has the best cell proliferation effect at a cobalt concentration of 2 ppm. Antioxidant activity assays showed that TPS-Co has better antioxidant activity than TPS in the concentration range of 0.4-2 mg/mL. Ultraviolet spectroscopy indicated that TPS-Co does not contain nucleic acids and proteins. Atomic absorption spectroscopy showed a cobalt content of 3.8%. Thermal performance analysis demonstrated that TPS-Co has higher thermal stability. Scanning electron microscopy and atomic mechanical microscopy demonstrated that TPS-Co has a more homogeneous and concentrated morphological distribution compared to TPS.
Fourier-transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy demonstrated that cobalt complexed successfully with TPS. In order to develop a novel immunomodulatory biomaterial, we synthesized polysaccharide cobalt complex (TPS-Co) to prevent the paradoxical effects of cobalt while maintaining its beneficial effects, and evaluated its morphology, structure, and antioxidant activity. Qingzhuan Dark Tea polysaccharides (TPS) has been shown to be a biomaterial with antioxidant and immunomodulatory effects. Cobalt has recently been shown to be a trace element that promotes bone growth. The paradoxical effects of cobalt in biological processes have caused controversy regarding the application of cobalt-based biomaterials.
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