Membrane technologies are among the most cost-effective ways to extract and purify hydrogen. Compared to distillation and pressure swing adsorption, the use of membranes is more energy-efficient and can potentially produce hydrogen with high purity (>99.5%). Various types of hydrogen-selective membranes have been developed, including carbon molecular sieves, dense metal membranes, silica-based membranes, polymeric membranes, and composite membranes. Among these, composite membranes are of particular interest. They utilise a variety of materials as supports, such as porous Vycor glass, metal substrates, polymers, and ceramics.

Ceramic supports offer several advantages, including a smoother surface with smaller nanometre-scale pores that enable the formation of thin, defect-free selective layers. Aluminium oxide is the most common ceramic support material, leveraging a combination of α and γ modifications to create a macroporous, highly permeable support structure coupled with a microporous transition layer. 

This study examines composite membranes featuring a porous ceramic support of anodic aluminium oxide, which imparts mechanical and thermal stability to the selective layer. The key advantage of using anodic aluminium oxide lies in the ability to control the geometric parameters of the support, such as pore diameter and the spacing between pore centres. This is achieved by adjusting the anodization conditions, including voltage, electrolyte composition, concentration, and temperature.

Selectivity in these membranes is provided by an active palladium layer deposited on the support. This layer should be as thin as possible while maintaining maximum gas tightness and minimal defects. Various deposition methods are employed to achieve this, including magnetron sputtering, chemical vapour deposition, and electrodeposition.

A distinctive feature of these composite membranes is their stability, achieved by a selective palladium layer formed both on the outer surface of the support and within the porous structure. This approach ensures strong adhesion of the sputtered selective layer.

As part of this study, methods were developed for synthesising composite membrane supports based on anodic aluminium oxide, with pore diameters ranging from 50 to 150 nm. Additionally, the conditions were determined for electrodepositing palladium into the support pores and sputtering a gas-tight selective palladium layer onto the outer surface of the composite membrane.

Laboratory tests were conducted to assess gas permeability of composite membranes using model mixtures, such as H2/N2, as well as complex gas mixtures containing carbon monoxide and carbon dioxide at the temperatures up to 400 °C. The study findings have scientific merit and practical relevance, as they facilitate generation of pure hydrogen at high production rates using materials that are competitively priced as compared to other types of membranes.

Graduated from Gubkin Russian University of Oil and Gas, Faculty of Chemical Technology and Ecology. He has extensive experience in the development of catalysts for oil refining, such as hydrotreating, reforming, isomerization. His research interests include new applications of PGMs and catalysts for chemical synthesis. He works in the Palladium Centre of Nornickel