Moving Beyond Noble Metals
In recent years, water electrolysis has gained significant attention as a method for producing green hydrogen, a clean chemical and energy vector. This is particularly valuable for hard-to-abate sectors and transportation, representing a key strategy for decarbonization.
Water electrolysis, is an electrochemical process that breaks down water (H2O) into its constituent elements, hydrogen (H2) and oxygen (O2), using an electric current.
This process occurs in an electrolytic cell consisting of two electrodes (anode and cathode) immersed in an electrolyte, a concentrated solution of KOH or NaOH in the context of alkaline water electrolysis.
A typical electrode consists of a metallic substrate that conducts electrons and an electrocatalytic coating. The coating speeds up the hydrogen or oxygen evolution reactions at the cathode and anode of the electrochemical cells, respectively.
Traditionally, noble metals, such as platinum and iridium, are used as electrocatalysts in electrolysis reactions to enhance the efficiency and kinetics of the process. They are specifically chosen due to their resistance to corrosion and high activity in promoting electrolysis reactions. Additionally, their stability ensures the long-term performance and durability of the electrochemical cell.
However, their high cost and limited global availability present significant challenges.
To overcome these obstacles, De Nora’s efforts to find solutions to minimize or even eliminate the content of noble metals from electrodes.
At the same time, the company is developing new metal-free electrodes capable of delivering comparable performances, such as stable voltage at high current densities, lower costs, and a reduced environmental footprint.
One approach is to develop new coating techniques to enhance the efficiency of non-noble metal catalysts. For instance, new formulations and architectures of electrocatalysts can be devised and then applied to the substrate, obtaining new electrodes.
With this approach, rare-earth and transition metals can be utilized in different forms and structures, unlocking performances comparable to noble metal-based electrocatalysts.
De Nora is also exploring alternative manufacturing techniques to produce electrocatalytic layers, especially for cathodes, that can maintain the process's kinetic efficiency and stability.
Alkaline water electrolysis is a pivotal technology for producing green hydrogen and advancing the energy transition. In this context, De Nora is actively engaged in promoting innovative solutions to reduce and remove the quantity of noble metals used as electrocatalysts, making this technology cleaner and more environmentally friendly.