H2 permeance and surface characterization of a thin (2 μm) Pd-Ni composite membrane prepared by electroless plating

چکیده مقاله

The high cost of palladium membranes limits their widespread use in industrial applications. We report a novel strategy for the preparation of economic hydrogen separation membranes. In this study, a Pd₈₈-Ni₁₂ composite membrane was prepared with a considerable nickel content (>10 wt%) for the first time using the organic–inorganic activation method in the ELP approach. The H₂ permeance of the Pd₈₈-Ni₁₂ composite membrane was 4.34 × 10^-7 mol m⁻² s⁻¹ Pa⁻¹ at 500 °C with infinite selectivity (H₂/N₂). The membrane exhibited suitable performance when exposed to binary mixtures under various operating conditions. At 500 °C and 100 kPa, with the same concentration of impurity gases, the H₂ permeance of the Pd₈₈-Ni₁₂ composite membrane was 3.33 × 10 ^-7 mol m⁻² s⁻¹ Pa⁻¹ for the H₂-Ar mixture, 3.12 × 10 ^-7 mol m⁻² s⁻¹ Pa⁻¹ for the H₂-N₂ mixture, 2.56 × 10 ^-7 mol m⁻² s⁻¹ Pa⁻¹ for the H₂-CO₂ mixture, and 2.54 × 10 ^-7 mol m⁻² s⁻¹ Pa⁻¹ for the H₂-CO mixture. The effect of operating parameters and the amount of impurity concentration in the gas feed on the stage cut in binary gas mixtures was investigated. Increasing operating temperature and pressure enhanced the stage cut for all mixtures while increasing the impurity concentration in the gas feed led to a decrease in the stage cut, independent of operating conditions. The Pd₈₈-Ni₁₂ composite membrane indicated suitable long-time permeance stability for 150 h at a transmembrane pressure range of 100–300 kPa and 500 °C under an H₂/N₂ gas atmosphere. Finally, the cost investigation demonstrated that the Pd₈₈-Ni₁₂ composite membrane had a 38 % lower specific cost than the pure palladium composite membrane.