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Performance Study on Cathode Microporous Layer Using Biomass Activated Carbon for Passive Direct Ethanol Fuel Cell

Ekdharmasuit Panuwat, Sapkitjakarn Jiratchaya, Sangwanangkool Phuritutphong, Bampenrat Akarasingh, Sukkathanyawat Hussanai

Journal of Ecological Engineering

2023

Vol. 24, nr 10

214--224

In passive direct ethanol fuel cells (DEFCs), the micro-porous layer (MPL) is a vital component of the membrane electrode assembly (MEA), facilitating gas-liquid mass transport and improving electronic conductivity. The conducted study involved preparing various carbon materials for the cathode MPL, including Ketjen Black (KB), activated carbon (AC) from Durian shells, and a 15% weight mixture of AC and KB (AC15%). Characterization of the activated carbon was carried out using nitrogen adsorption-desorption isotherm analysis. Additionally, various electrochemical techniques, including cell polarization, electrochemical impedance spectroscopy (EIS), anode half-cell polarization, and anode EIS, were conducted to examine the effects of the cathode MPLs on cell performance. The results indicated that the cell with the conventional KB cathode MPL displayed the highest performance, whereas the AC15% and AC cathode MPLs showed relatively lower performances, respectively. The AC cathode MPL in the cell encountered challenges, such as decreased pore volume, increased micropores, and a hydrophobic electrode nature, leading to reduced gas transport resulting in poor cell performance. In contrast, the AC15% cathode MPL, which combined AC and KB in the electrode, achieved an appropriate micropore and mesopore balance. However, performance did not improve due to a heterogeneous contact surface between the cathode catalyst layer and the cathode MPL, resulting in higher ohmic resistance. Incorporating biomass-based materials into the electrode presents an interesting possibility due to the utilization of cheap and readily available precursors, as well as the ability to tailor morphology. Conducting a systematic study of durian shell activated carbons would reveal improved properties of the carbon material suitable for implementing in the MPL of passive DEFCs.

Characterization of microporous oxide layer synthesized on Ti–6Al–7Nb alloy by micro-arc oxidation

Moskalewicz T., Kruk A., Kot M., Kayali S., Czyrska-Filemonowicz A.

Archives of Civil and Mechanical Engineering

2014

Vol. 14, no. 3

370--375

In this work a microporous oxide layer was formed on two phase (α+β) Ti–6Al–7Nb titanium alloy by the micro-arc oxidation process in an electrolyte containing (CH3COO)2CaH2O and Na3PO4. The thickness of the surface layer was in the range of 2.7 μm–3.6 μm. Microstructure of the surface layer and the substrate alloy was characterized with use of scanning- and transmission electron microscopy as well as by X-ray diffractometry. The microstructure of the surface layer consisted of TiO2 rutile and anatase nanocrystals as well as of amorphous regions containing mainly Ti, Ca and O atoms and a minority of P, Al and Nb ones. The surface layer was highly porous. The open pores, with diameter up to 6 µm, were homogenously distributed in the specimen surface. Electron tomography was used to investigate the pores morphology and spatial distribution. It was found that open pores exhibited a complex geometry. The closed pores had nearly spherical shape. Adhesion of the surface layer to the titanium alloy substrate was investigated by means of the scratch-test. The value of critical load LC2=14 N indicates a good layer adhesion to the underlying substrate.

Modern trends in developing joint endoprostheses

Pinchuk L.

International Journal of Applied Mechanics and Engineering

2002

Vol. 7, Spec. is

35-40

Concepts of approximating endoprostheses to natural joints are stated, namely application of polymer units similar to natural cartilage, generation of electret charge on the polymer members and transformation of the metal unit into a source of magnetic field.