Design of group 5 metal-based alloy membranes with high hydrogen permeability and strong resistance to hydrogen embrittlement

A Review for Consistent Analysis of Hydrogen Permeability through Dense Metallic Membranes

“…Hydrogen-permeable membranes are important materials for separating and purifying hydrogen gas from a gas mixture [2] produced by the electrolysis [3], steam reforming of hydrocarbon [4], chemical reactions of biomass [5], decomposition reactions of energy carriers [6,7], and so on. Hydrogen-permeable dense metallic membranes can achieve excellent purity of hydrogen gas, which are caused by their characteristic hydrogen permeation mechanism [8]. Hydrogen molecules separate into hydrogen atoms on a surface of a metallic membrane at the feed side (high pressure side) and dissolve into the membrane.…”

Experimental and Theoretical Insights into the Potential of V2O3 Surface Coatings for Hydrogen Permeable Vanadium Membranes

“…However, vanadium (V) is significantly cheaper and has a higher H 2 permeability than Pd, but it is a weak catalyst for H 2 dissociation and has tightly bound native oxides further inhibiting dissociation. , To fabricate hydrogen permeable V membranes, the native oxide must be removed, and protective H 2 dissociation overlayers must be deposited on the surfaces to instill catalytic activity and inhibit oxidation. Pd is typically used as an overlayer, and composite membranes using this configuration have achieved hydrogen permeability approaching theoretical values for V. , Nonetheless, Pd overlayers degrade when membranes are operated above 673 K due to interdiffusion between Pd and V. − Additionally, operation below 673 K is challenging due to V embrittlement induced by the enormous H solubility at moderate pressures. , Therefore, low H 2 pressures are required to ensure that the H concentration in the metal remains below the ductile-to-brittle transition concentration (DBTC) of 0.2 H/M. , …”

“…Pd is typically used as an overlayer, and composite membranes using this configuration have achieved hydrogen permeability approaching theoretical values for V. 4,5 Nonetheless, Pd overlayers degrade when membranes are operated above 673 K due to interdiffusion between Pd and V. 5−7 Additionally, operation below 673 K is challenging due to V embrittlement induced by the enormous H solubility at moderate pressures. 8,9 Therefore, low H 2 pressures are required to ensure that the H concentration in the metal remains below the ductile-to-brittle transition concentration (DBTC) of 0.2 H/M. 8,10 Many groups have explored alloys to suppress solubility and allow for increased operating pressures, but operating temperature is still limited below 673 K due to interdiffusion.…”

“…8,10 Many groups have explored alloys to suppress solubility and allow for increased operating pressures, but operating temperature is still limited below 673 K due to interdiffusion. 4,[11][12][13]9,14,15 Recently, self-supported tubular geometries have demonstrated the ability to exceed DBTC limitations in unconstrained modules. 16,17 Alternatively, different catalyst layers can be applied to reduce interdiffusion issues and allow operation well above 673 K. Our group has demonstrated this with ∼20 nm Mo 2 C layers on V foil, 18,19 which transport H via a spillover mechanism, where the H surface diffuses along grain boundary defects to reach the bulk V lattice.…”

Glass frit sealing method for macroscopic defects in Pd-based composite membranes with application in catalytic membrane reactors

“…Palladium and its alloys have garnered significant interest in the field of hydrogen separations for decades due to the ability of palladium to selectively transport hydrogen while maintaining good structural integrity. Although other metals, including vanadium, niobium and tantalum, have also been studied as hydrogen transport membranes [1][2][3], these metals are susceptible to severe hydrogen-induced embrittlement that is much more easily avoided in Pd-alloy systems [4,5]. Yet, implementation of palladium as a wide-scale hydrogen separation system has been hindered because of the metal's natural scarcity combined with its desirable catalytic properties, which make it one of the most expensive metals.…”