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

AGUSTINA DALLA FONTANA; NOELÍ SIRINI; LAURA CORNAGLIA; ANA TARDITI

JOURNAL OF MEMBRANE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018

0376-7388

Using the electroless deposition technique withdifferent deposition sequences, it was possible to obtain a single phase PdAgAuternary alloy after treatment at 773 K during 7 days. Despite the order of deposition,the samples exhibited similar hydrogen permeation flux at the same temperatureand pressure. In the presence of CO, the PdAgAu ternary alloy membranes showeda lower inhibition on the hydrogen permeance compared with the binary PdAualloy at 623 and 673 K. On the contrary, under CO2 containingstreams, the ternary alloy showed a higher inhibition with a complete hydrogenrecovery after removing CO2 from the stream. When H2S wasintroduced in the 13% CO2/13% Ar/74% H2 stream, a higher permeancedecrease was observed on both the PdAu and PdAgAu alloy membranes. Afterremoval of H2S, a hydrogen recovery of 60% and 76% was measured forthe PdAu and PdAgAu membranes, respectively. Pd surface segregation was observedon the Pd82Ag15Au3-873K-5d and the Pd78Au6Ag16-773K-7dsamples upon exposure to CO containing streams. Instead, silver surfacesegregation was observed by XPS after exposing the PdAgAu ternary alloy to CO2containing streams.