Environmental Sustainability Tag

Hydrogen is recognised as a clean energy carrier that could play a key role in reducing global carbon emissions. In Proton Exchange Membrane Water Electrolysers (PEM WE), the hydrogen evolution reaction (HER) takes place at the cathode, where protons from the acidic electrolyte combine with electrons to form hydrogen gas. Catalysts are essential to this process, as they reduce the activation energy required for the reaction. Noble metals such as platinum are the benchmark materials for HER catalysts due to their exceptional activity and stability. However, their scarcity and high cost limit large-scale adoption. Non-noble catalysts, including transition metal-based materials such as nickel, molybdenum, and cobalt compounds, are attractive alternatives due to their lower cost and abundance. Despite these advantages, non-noble catalysts are more susceptible to degradation under the acidic conditions of PEM WE.   The degradation of non-noble metal catalysts can arise from several processes, which often are interdependent. While the...

Recycling as a key of material circularity and societal acceptance   Production of energy from renewable sources is one of the keys to face the ongoing environmental crisis. The intermittency of renewable energies (wind, solar) pushed the emergence of energy storage technologies and industries such as the battery industry for storage as electrical energy, or the hydrogen industry for storage as chemical energy. Hydrogen can be produced through water electrolysis during energy overproduction periods to be transported and used on a different location and time using fuel cells, and notably Proton Exchange Membrane Fuel Cells (PEMFCs). These devices can convert hydrogen back into electricity and only emit water and heat, however, they rely on the use of raw materials that are expensive and can be critical or pose environmental issues such as platinum group metals, and perfluorinated polymers. There is a necessity to guarantee the recyclability of the constitutive materials of new...