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Mehri-Saddat Ekrami-Kakhki,Sedigheh Abbasi,Nahid Farzaneh 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.1
XCThepurpose of this study is to statistically analyze the anodic currentdensity and peak potential of methanol oxidation at Pt nanoparticlessupported on functionalized reduced graphene oxide (RGO), usingdesign of experiments methodology. RGO is functionalized with methylviologen (MV) and chitosan (CH). The novel Pt/MV-RGO-CH catalystis successfully prepared and characterized with transmission electronmicroscopy (TEM) image. The electrocatalytic activity of Pt/MV-RGOCHcatalyst is experimentally evaluated for methanol oxidation. Theeffects of methanol concentration and scan rate factors are alsoinvestigated experimentally and statistically. The effects of these twomain factors and their interactions are investigated, using analysis ofvariance test, Duncan’s multiple range test and response surface method. The results of the analysis of variance show that all the main factors andtheir interactions have a significant effect on anodic current density andpeak potential of methanol oxidation at α = 0.05. The suggested modelswhich encompass significant factors can predict the variation of theanodic current density and peak potential of methanol oxidation. Theresults of Duncan’s multiple range test confirmed that there is asignificant difference between the studied levels of the main factors.
Mehri-Saddat Ekrami-Kakhki,Nahid Farzaneh,Sedigheh Abbasi,Hadi Beitollahi,Seyed Ali Ekrami-Kakhki 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.5
In this research, graphene oxide was prepared by a modified Hummers’ method, and then functionalized with 1, 1′-dimethyl-4, 4′-bipyridinium dichloride (MV), and chitosan (CH) to get a MV–RGO–CH support. Pt nanoparticles were preparedon this support to get Pt/MV–RGO–CH catalyst. The morphology and microstructure of Pt/MV–RGO–CH catalyst werecharacterized with transmission electron microscopy image and X-ray diffraction analysis. The electrocatalytic activity ofthe prepared catalyst towards ethanol oxidation was investigated by carbon monoxide stripping voltammetry, cyclic voltammetry,and electrochemical impedance spectroscopy techniques. The effects of some experimental parameters such as scanrate, ethanol concentration, and temperature were investigated for ethanol electrooxidation at Pt/MV–RGO–CH catalyst. Durability of the catalyst was also investigated. The electrocatalytic performance of Pt/MV–RGO–CH catalyst for ethanoloxidation was compared with those of Pt/CH and Pt/MV–RGO catalysts. The higher electrocatalytic performance of Pt/MV–RGO–CH than Pt/CH and Pt/MV–RGO catalysts towards ethanol electrooxidation indicated that Pt/MV–RGO–CHcould be a promising catalyst for application in direct ethanol fuel cells.
Ali Koroushavi,Zakareya Hamad Allah Jashoei,Sedigheh Abbasi 한국자원공학회 2020 Geosystem engineering Vol.23 No.2
The viscosity of nanofluids is affected by several factors such as temperature and weight fraction. In this study, we investigate for the first time the effect of them on the viscosity of nanofluids containing MWCNTs-Ag, with different amount of Ag nanoparticles (MWAg-1 and MWAg-2) using 2-level factorial design. The results of FTIR and XRD analysis confirm the presence of synthesized Ag nanoparticles on the surface of MWCNTs. TEM results reveal that Ag nanoparticles can successfully introduce on the surface of oxidized MWCNTs. The results of the analysis of variance (ANOVA) confirm that both models are significant for viscosity prediction of nanofluids. Meanwhile, the results reveal that the temperature (40 ∘C and 70 ∘C) and weight fraction (0.125 and 0.5) have a significant effect on the viscosity of MWAg-1 nanofluids. In addition, the results confirmed that the importance of temperature is more than the concentration of MWAg-1. The contribution percent of temperature and weight fraction reveals that the contribution of weight fraction (44.08) is higher than that of temperature (37.71°C) at the proposed model. However, in the MWAg-2 nanofluids, only the temperature has a significant effect on the viscosity. The F-values of model in MWAg-1and MWAg-2 nanofluids are 20.21 and 15.70, respectively.