R-016

Muhammad Adil Riaz

muhammadadil.riaz@ucl.ac.uk

Marc-Olivier Coppens

Centre for Nature Inspired Engineering & Department of Chemical Engineering, University College London, United Kingdom

Nature-inspired electrodes for efficient gas bubble management of water electrolysers

Excessive use of fossil fuels in the last century to meet the energy demand of a rapidly growing population has drastically increased carbon dioxide and other greenhouse gas emissions. Green hydrogen production by the application of renewable electricity in water electrolysers can play a key role in decarbonising the energy infrastructure with net zero emissions. During the electrolysis process, two half-cell electrochemical reactions occur over separate electrodes; the hydrogen evolution reaction (HER) at the negative electrode called the cathode, and the oxygen evolution reaction (OER) at the positive electrode called the anode. These oxygen and hydrogen gases produced during the electrolysis need to be kept separate to prevent the formation of an explosive mixture. Moreover, bubbles formed from these gases cause performance losses in electrochemical reactions due to an increase in activation and Ohmic overpotentials. Currently, membranes are employed to prevent gas crossover in commercial water electrolysers such as proton exchange membranes and anion exchange membranes are employed at the industrial level. However, the membrane is a major source of electrical resistance in the cell and undergoes irreversible degradation at high temperatures. For membrane-less water electrolyser designs, the current density in operation is much lower, as the interelectrode distance needs to be kept much larger to prevent gas mixing in the electrolyte chamber. Novel electrode designs that can mitigate their bubble accumulation are highly desirable in water electrolysers. Bioinspiration from various natural systems, performing gas bubble manipulation at the microscopic scale, can provide an effective strategy for electrode designs. In this work, electrodes for effective gas bubble management in water electrolysers are designed using a systematic Nature-Inspired Chemical Engineering (NICE) methodology.