Saudi researchers produce hydrogen from seawater

In Saudi Arabia, seawater, which comprises more than 95% of the Earth’s water, could become a key resource in the sustainable production of clean hydrogen fuel with use of water-splitting catalysts developed by a team from the King Abdullah University of Science and Technology.

Water splitting could offer an appealing way to carbon neutrality, especially when coupled with renewable energy sources such as solar and wind power. Water splitting involves the breakdown of water in an electrochemical cell to produce hydrogen at the cathode while generating oxygen at the anode under applied voltage. Yet, hydrogen and oxygen evolution catalysts that perform well in fresh water become less effective in seawater because of abundant ions that can promote unwanted reactions and poison catalysts.

Highly corrosive chloride ions present in seawater undergo complex reactions that compete with oxygen evolution and generate harmful compounds, such as hypochlorite. Because hydrogen production hinges on stable and efficient reactions at both electrodes, these ions are a major challenge for seawater splitting.

The team devised an approach that provides high-efficiency and stable hydrogen evolution electrocatalysts for seawater splitting. The researchers created tiny cubic reactors, in which the catalyst was encased in a molybdenum sulfide protective shell. The catalyst core consisted of a carbon-supported molybdenum-based redox active compound and featured a zeolite-like ordered nanoporous structure.

The researchers are now designing advanced catalysts with specific configuration to achieve a more sustainable energy conversion during seawater splitting. They are also investigating the structural evolution and behavior of the reactive centers during the catalytic process to gain in-depth knowledge of the seawater splitting technique for future advancement and mass commercialization.

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