Hydrogen permeation and surface properties of PdAu and PdAgAu membranes in the presence of CO, CO2 and H2S

CORNAGLIA, LAURA M.; SIRINI, NOELÍ; DALLA FONTANA, AGUSTINA; TARDITI, ANA M.

JOURNAL OF MEMBRANE SCIENCE

ELSEVIER SCIENCE BV

Año: 2018 vol. 563 p. 351 - 359

0376-7388

Using the electroless deposition technique with different deposition sequences, it was possible to obtain a single phase PdAgAu ternary alloy after treatment at 773 K during 7 days. Despite the order of deposition, the samples exhibited similar hydrogen permeation flux at the same temperature and pressure. In the presence of CO, the PdAgAu ternary alloy membranes showed a lower inhibition on the hydrogen permeance compared with the binary PdAu alloy at 623 and 673 K. On the contrary, under CO2 containing streams, the ternary alloy showed a higher inhibition with a complete hydrogen recovery after removing CO2 from the stream. When H2S was introduced in the 13% CO2/13% Ar/74% H2 stream, a higher permeance decrease was observed on both the PdAu and PdAgAu alloy membranes. After removal of H2S, a hydrogen recovery of 60% and 76% was measured for the PdAu and PdAgAu membranes, respectively. Pd surface segregation was observed on the Pd82Ag15Au3?873 K-5 d and the Pd78Au6Ag16?773 K-7 d samples upon exposure to CO containing streams. Instead, silver surface segregation was observed by XPS after exposing the PdAgAu ternary alloy to CO2 containing streams.