Journal of Membrane Science & Technology

Dynamics of hydrogen permeation across mono- and bi-layer hollow cylinders: Electrochemical and gas-phase impedance spectroscopy analysis

2^nd International Conference on Membrane Science and Technology

September 13-14, 2018 | London, UK

Pierre Millet

Paris-Sud University, France

Scientific Tracks Abstracts: J Membr Sci Technol

Abstract:

Hydrogen is a chemical energy vector of increasing interest in view of the so-called ???hydrogen economy???. It can be obtained from natural hydrocarbons (e.g. from natural gas using steam reforming) or from water using electrolysis. High purity hydrogen is required for various applications such as PEM fuel cells for the automotive industry. Hydrogen permeation through metal-absorbing materials is an interesting technical option for hydrogen extraction/purification from miscellaneous gas mixtures. The purpose of this communication is to discuss some recent developments related to hydrogen purification by permeation through metallic mono- (ML) and bi- (BL) layer full/hollow cylinders (analysis of transport in cylindrical coordinates). The kinetics of hydrogen permeation is analyzed using electrochemical (EIS) and gas-phase (GPIS) impedance spectroscopies. GPIS is a technique initially developed for analyzing hydrogen sorption in hydride-forming materials and later used for analyzing hydrogen permeation processes. First, the thermodynamics, transport mechanism and kinetics of hydrogen permeation across metals are briefly reviewed. Experimental EIS and GPIS impedance spectra measured on ML and BL full/hollow cylinders are compared and analyzed. These experimental data are fitted using analytical expressions developed to account for hydrogen transport in cylindrical coordinates. Microscopic rate parameters are deduced from these fit and discussed. Practical experimental conditions required to separate the contributions of the different layers (i.e. individual layer composition and thickness, hydrogen solubility and diffusivity, operating temperature) are analyzed. The interest of using multi-layer hollow cylinders for permeation will be discussed. The behavior of bi-layer hollow cylinders containing a thin surface palladium layer atop bulk palladium-silver and palladium-copper materials are more specifically considered. The behavior of such systems in transient conditions of flow will also be described and analyzed. Recent Publications 1. Ngameni R and Millet P (2014) EIS analysis of hydrogen incorporation into Pd-based planar, spherical and cylindrical bi-layers. Electrochimica Acta 131:52???59. 2. Millet P, Ngameni R, Decaux C and Grigoriev S (2011) Hydrogen sorption by Pd77Ag23 metallic membranes: role of hydrogen content, temperature and sample microstructure Int. J. Hydrogen Energy 36:4262???4269. 3. Decaux C, Ngameni R, Solas D, Grigoriev S and Millet P (2010) Time and frequency domains analysis of hydrogen permeation across PdCu metallic membranes for hydrogen purification. Int. J. Hydrogen Energy 35:4883???4892. 4. Decaux C, Mehdoui T, Ngameni R, Ranjbari A and Millet P (2009) Frequency-domain analysis of hydrogen permeation across Pd77Ag23 metallic membranes. Int. J. Hydrogen Energy 34:5003???5009. 5. Millet P (2005) Pneumato-chemical impedance spectroscopy: (I) principles. J. Phys. Chem. 109:24016???24024.

Biography :

Pierre Millet is an Electrochemical Engineer and Professor of Physical-Chemistry at the University of Paris-Sud. He graduated in 1986 from the French École Nationale Supérieure d'Électrochimie et d'Électrométallurgie de Grenoble (ENSEEG) at the “Institut Polytechnique de Grenoble” (INPG). He completed his PhD thesis on Water Electrolysis in 1989, at the French Centre d'Études Nucléaires de Grenoble (CEA-CENG). He is currently heading the Laboratory of Research and Innovation in Electrochemistry for Energy Applications, at the French Institute of Molecular Chemistry and Material Science (Paris-Sud University). His research activities are focused on water electrolysis, water photo-dissociation, carbon dioxide electro- and photo-reduction, hydrogen storage in hydride-forming materials, hydrogen compression and hydrogen permeation across metallic membranes. He is the Author of more than 150 research papers and book chapters and has presented over 150 oral communications at national and international conferences.

E-mail: pierre.millet@u-psud.fr