The importance of the shape of Cu2O nanocrystals on plasmon-enhanced oxygen evolution reaction in alkaline media
Résumé
Cu2O nanostructures of cubic or octahedral shape as well as decorated with gold nanoparticles were synthesized by a chemical process. The electrochemical activity of these nanostructures for the oxygen evolution reaction (OER) in alkaline media was assessed in the dark and under solar light irradiation. Electrodes modified with cubic-shaped Cu2O and Cu2O-Au nanostructures revealed both enhanced electrocatalytic OER activity over the octahedral-shaped ones, for which hydroxylation of the (111) surfaces might hinder the OER as supported by numerical computations. Illumination of Cu2O nanostructures with solar light did not enhance the electrocatalytic OER. Cu2O-Au nanostructures, however, showed improved OER activity with an overpotential of 200 mV (10 mA cm−2) and a Tafel slope of 97 mV dec−1. The enhanced OER activity was ascribed to increased light absorption due to the plasmonic properties of Cu2O-Au cubes.
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