Palladium membranes have shown great potential for the purification of hydrogen gas. As the demand for pure hydrogen continues to grow in various industries, the need for efficient and cost-effective purification methods becomes increasingly important. Palladium membranes offer a promising green solution due to their high selectivity and permeability for hydrogen gas.
“Production of hydrogen from hydrocarbons remains the main hydrogen source. Before its use in proton exchange membrane (PEM) fuel cells, hydrogen must be separated from gas mixtures and purified,” said Sergey Saltykov, Nornickel’s Head of R&D. He added that membrane purification stands out as a promising method for this stage.
The goal is to use a membrane that allows hydrogen to pass through but blocks other gas mixture components. “Palladium is uniquely ‘transparent’ to hydrogen, enabling it to exclusively pass hydrogen, a property that sets palladium apart from other platinum group metals,” Saltykov explained.
Commercially, these membranes are often a thin palladium layer on a substrate of various types. A significant technological challenge is ensuring strong adhesion between the film and the substrate.
“In our products, we plan to integrate multiple physical and electrochemical methods to prepare membranes with enhanced adhesion, thereby prolonging service life and optimizing the hydrogen permeance/selectivity ratio. Consequently, we introduce new palladium membranes that exhibit superior hydrogen performance and extended service life compared to existing commercial counterparts,” Saltykov elaborated.
The primary advantage of palladium membranes in hydrogen purification is their selectivity, allowing only hydrogen to pass while blocking other gases. This capability stems from palladium’s unique properties, enabling hydrogen to dissolve into its metal lattice and diffuse through, while blocking other gases.
With their improved adhesion, these membranes are highly effective in separating hydrogen from gas mixtures, ideal for hydrogen production, fuel cells, and various industrial processes. Their excellent hydrogen permeability ensures efficient transport across the membrane at high rates, suitable for large-scale purification processes. They offer a sustainable and cost-effective alternative to traditional methods like pressure swing adsorption or cryogenic distillation, due to their lower energy requirements and smaller operational footprint.
Moreover, these membranes can function at high temperatures, enhancing their performance and making them suitable for industrial applications. Operating at elevated temperatures increases hydrogen flux and aids in removing impurities like carbon monoxide and sulfur compounds, often found in hydrogen sources.
Despite the advantages, palladium membranes face challenges, particularly their vulnerability to poisoning by impurities such as sulfur and carbon monoxide. Ongoing research is directed towards developing palladium-based alloys and composite membranes with enhanced resistance to these impurities, alongside improved mechanical and thermal stability.
Palladium membranes hold significant promise for hydrogen gas purification, characterized by high selectivity, permeability, and operational capability at high temperatures. As the demand for pure hydrogen escalates, advancing palladium membrane technology will be pivotal for various industries, including fuel cells, ammonia production, and petrochemicals. Continued research and development could position palladium membranes as a central technology for adopting clean hydrogen as a sustainable energy carrier.
Palladium’s use in electrochemical water disinfection devices
· Palladium can be a better catalyst for water disinfection than other metals
· Trials of new compounds with palladium for water purification are currently underway
Clean water is the foundation of human health and the health of the planet. It is a limited resource globally, and new water treatment technologies are needed to address this pressing problem.
One of the main methods of water disinfection — mainly seen in industry and in swimming pools — is the use of a powerful chemical agent, sodium hypochlorite (chlorine).
However, there are drawbacks to this method when used in industrial settings, including the need to store large quantities of hypochlorite, the necessity to dispose of unused reagent after its expiration date, and the requirement for additional personnel to operate the system.
A promising alternative method for water disinfection is the electrolysis of a solution of common table salt to produce hypochlorite on-site. It is one of the most promising techniques for water disinfection.
Special catalysts based on iridium and ruthenium are required to produce hypochlorite from table salt. These catalysts are used in commercial water disinfection devices and serve as commercial analogs for new prototypes.
However, a viable alternative exists. Chemist Dmitry Korolev said, “Palladium has shown promising results replacing iridium and ruthenium in the catalyst composition, with tests showing enhanced catalytic activity.”
“In the very near future, we will present a new technology, an electrode with palladium for electrochemical disinfection of water. Now we are at the stage of synthesis of experimental samples for research in laboratory conditions and determination of the optimal chemical composition,” Korolev added.
“That technology allows to increase the activity of the catalyst and the chlorine output by current, and makes the process more economical and affordable,” he further mentioned.
In July last year, Russian miner Nornickel, the world’s largest palladium producer, said it was actively developing a new composition of a palladium-based catalytic layer for application to electrodes. Researchers saw a possibility of synergistic effect of catalytic properties with other platinum group metals and increasing the service life of palladium-based catalytic coating.
“Electrolysis technology for water disinfection is just gaining momentum, but in the future, it may become a basic technology, and may also be used to treat drinking water,” Vitaly Busko, Nornickel’s vice president for innovation, said.
According to preliminary estimates, the use of palladium for electrochemical disinfection of water will require a relatively small amount of metal, or 0.6 milligrams per one catalyst unit. However, despite the high cost of palladium compared to other catalytic materials, the process will ultimately prove to be more cost-effective due to higher water treatment rates and, in the long term, the possibility of deeper treatment. Moreover, the use of palladium catalysts is a more environmentally friendly solution.
Currently, experimental prototypes of palladium-based compounds are being synthesized for laboratory testing to determine the optimal chemical composition. Once the trials are finished, a new electrode with palladium for electrochemical water disinfection will be introduced for commercial use.
The proposed technology allows for increased catalyst activity and chlorine production per unit of electricity, making the process more efficient and accessible. By utilizing palladium as a catalyst in electrochemical water disinfection devices, the new technology has the potential to revolutionize the water treatment industry.
This development has the potential to provide a more efficient and sustainable palladium-based solution for crystal clear and bacteria-free water on a global scale. As efforts continue to enhance the efficiency of water disinfection methods, the use of palladium in electrochemical devices will play a significant role in addressing the global challenge of clean water access.
