Electrochemical water oxidation with carbon-grafted molecular catalysts

Hydrogen production via water splitting represents a potential cost-effective solution to harvest and store energy using the sun as the energy source. This process requires active and robust catalysts that can oxidize water to provide electrons for proton reduction. Identifying molecules or materials to achieve efficient catalytic water oxidation remains a challenge. We have developed a new strategy to perform electrochemical water oxidation with molecular catalysts attached to carbon electrodes. A direct covalent bond is formed between the electrode and catalyst via diazonium grafting of Ir and Ru complexes. Driving immobilized catalysts electrochemically provides an alternative way to evaluate the water oxidation activity. Catalyst loading can be quantified, and stability over time can be monitored. This new surface attachment method allows for systematic evaluation of the activity and stability of catalysts. Combining this strategy with newly developed catalysts could lead to a solution for storing solar energy in chemical fuels.