Laser synthesis of palladium-alumina composite membranes for production of high purity hydrogen from gasification

This paper describes a special method of laser-based deposition to synthesize palladium-ceramic composite membranes. Thin film Pd was deposited on a ceramic substrate by Nd-YAG laser irradiation of coating precursor PdCl2 on γ-alumina substrate. The parameters of the laser processing technique were optimized to synthesize metal-ceramic composite membranes. The physical and chemical characteristics of Pd coated γ-alumina membranes were studied and compared with various other alumina membranes referenced in the literature. Hydrogen permeation experiments were performed in a CO + CO2 + CH4 + H2 environment under typical catalytic steam gasifier exit conditions. The Pd-ceramic composite showed good mechanical and thermal stability and resulted in a hydrogen permeability flux of about 0.061 mol/m2 s. The activation energy of the Pd membrane was found to be 5.39 kJ/mol in a temperature range of 900-1300 °F.