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Kumaresan, N., Karuppasamy, P., Kumar, M. P., Peera, S. G., AlSalhi, M. S., Devanesan, S., et al. (2023). Synthesis and characterization of metal-free nanosheets of carbo-catalysts for bifunctional electrocatalyst towards HER and OER application. Mol. Catal., 539, 113043.
Abstract: Production of “green hydrogen” through water electrolysis is attracting considerable attention in recent years, due to the high demand for green energy technologies. The efficiency of water electrolysis depends on the electrocatalytic activity of anodic and cathodic electrocatalysts. Currently, utilizing Pt and RuO2-based elec-trocatalysts is expensive in terms of commercial aspects. Therefore, growing research for inventing efficient and cheap electrocatalysts is undergoing rigorously. In this work, we have synthesized, biomass-derived electro-catalysts with intrinsically implanted heteroatoms as hydrogen and oxygen evolution reactions in alkaline electrolytes. The biomass carbon catalyst is derived from the carbonation of the Acorus Calamus plant “root”. The derived carbon is activated by KOH treatment (C-750). The resultant carbon powder is characterized by various physiochemical and electrochemical characterization techniques. The C-750 catalyst is found to have excellent morphology, surface area (3488 m2/g), pore size (4.08 nm), pore volume (1.10 cc/g), and intrinsically doped N. The HRTEM analysis of C-750 reveals well-distributed microporous and graphitic surfaces. When used as an electrocatalyst for HER and OER analysis, the C-750 exhibited appreciable electrocatalytic activity with an overpotential of-0.330 V and 0.563 V vs. RHE, respectively at the current density of-10.0 mA/cm2. In addition, the C-750 catalyst also showed excellent stability with almost zero degradation in a chronoamperometric measurement carried out for 10 hrs.
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Slane, J., Vivanco, J., Meyer, J., Ploeg, H. L., & Squire, M. (2014). Modification of acrylic bone cement with mesoporous silica nanoparticles: Effects on mechanical, fatigue and absorption properties. J. Mech. Behav. Biomed. Mater., 29, 451–461.
Abstract: Polymethyl methacrylate bone cement is the most common and successful method used to anchor orthopedic implants to bone, as evidenced by data from long-term national joint registries. Despite these successes, mechanical failure of the cement mantle can result in premature failure of an implant which has lead to the development of a variety of techniques aimed at enhancing the mechanical properties of the cement, such as the addition of particulate or fiber reinforcements. This technique however has not transitioned into clinical practice, likely due to problems relating to interfacial particle/matrix adhesion and high cement stiffness. Mesoporous silica nanoparticles (MSNs) are a class of materials that have received little attention as polymer reinforcements despite their potential ability to overcome these challenges. Therefore, the objective of the present study was to investigate the use of mesoporous silica nanoparticles (MSNs) as a reinforcement material within acrylic bone cement. Three different MSN loading ratios (0.5%, 2% and 5% (wt/wt)) were incorporated into a commercially available bone cement and the resulting impact on the cement's static mechanical properties, fatigue life and absorption/elution properties were quantified. The flexural modulus and compressive strength and modulus tended to increase with higher MSN concentration. Conversely, the flexural strength, fracture toughness and work to fracture all significantly decreased with increasing MSN content. The fatigue properties were found to be highly influenced by MSNs, with substantial detrimental effects seen with high MSN loadings. The incorporation of 5% MSNs significantly increased cement's hydration degree and elution percentage. The obtained results suggest that the interfacial adhesion strength between the nanoparticles and the polymer matrix was poor, leading to a decrease in the flexural and fatigue properties, or that adequate dispersion of the MSNs was not achieved. These findings could potentially be mitigated in future work by chemically modifying the mesoporous silica with functional groups. (C) 2013 Elsevier Ltd. All rights reserved.
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