부산대학교 도서관

This work prepared a novel PdCu-coated Nb30Hf35Co35 self-supported membrane by regulating the composition of the outermost catalytic film, and we report its performance in gas mixtures containing H2S for the first time. The results show that this membrane not only has higher pure H2 permeation performance but also excellent H2S resistance. At 120 ppm H2S in the feed, the permeability of this membrane is 1.6 × 10–8 mol H2 m−1 s−1 Pa−0.5 at 673 K, which is 3.2 (8.1) times that of the Pd-coated counterpart (and pure Pd). Furthermore, this membrane can be stable for at least 240 h. By first-principles calculations, our results also showed that alloying Pd with Cu inhibits the formation of palladium sulphide (e.g., Pd4S), thus providing more activating active sites for hydrogen adsorption and dissociation. This could be the main reason for the improvement of hydrogen permeability of PdCu-coated composite membranes in an H2S atmosphere. This study suggests that appropriately adjusting the type or composition of the catalytic layer is an effective method to alleviate membrane H2S poisoning, an aspect not widely studied in 5B group alloys. [ABSTRACT FROM AUTHOR]