A novel Nb-based hydrogen purification membrane without catalytic palladium overlayer

Recently, group 5 metals and related alloys are considered as promising hydrogen permeation membranes to replace commercial palladium and its alloys. However, almost all these alloy membranes need to be coated with a noble Pd catalytic layer, which is complicated and costly. Therefore, one of the important R&D aspects is to explore "non-Pd" membranes. To address this challenge, we innovatively used vanadium and its oxide layer to replace Pd in the "core" materials of these membranes, and then developed a new type of Nb-based hydrogen purification membrane without a catalytic Pd overlayer. The base-metal Nb15Ti55Fe30 layer, produced by the directional solidification method, not only exhibits excellent hydrogen permeation performance, but also has good hydrogen embrittlement resistance. After testing, the novel composite membrane showed a high hydrogen permeability of 6.07 × 10−8 mol H2 m−1 s−1 Pa−1/2 at 773 K, which is ca. 3.8 times that of pure Pd. More importantly, the price of this novel membrane is at least two orders of magnitude cheaper than that of a Pd membrane. This work opens up a new way for large-scale practical application of Nb-based membranes, and the developed "non-Pd" composite membrane has wide application prospects.