Life Cycle Assessment and Critical Raw Materials Analysis of Innovative Palladium-Substituted Membranes for Hydrogen Separation

Palladium-based membranes for hydrogen separation offer the most promising gas permeation and selectivity, but their large-scale application has been limited due to the high environmental burdens and criticality of palladium. Herein, the possibility of substituting Pd with candidate elements in the composition of metallic membranes deposited via High Power Impulse Magnetron Sputtering (HiPIMS) was investigated. This study proposed an innovative framework for a more comprehensive investigation of the sustainability challenges related to this lab-scale technology by integrating LCA and criticality analyses, thereby supporting materials selection efforts. First, the criticality status of several elements used in hydrogen separation membranes was screened with two different approaches. Furthermore, the environmental impacts of novel membrane compositions were compared with a high Pd-content reference membrane (Pd77Ag23) through cradle-to-gate Life Cycle Assessment (LCA). For robust LCA modeling, uncertainty analysis was performed via Monte Carlo simulation exploiting errors estimated for primary data. A direct relationship was identified between the Pd content in membranes and the associated environmental impacts. VPd membranes proved to be the most promising candidate by exhibiting 65% lower total impacts than the PdAg membrane while maintaining a high hydrogen permeability performance.