Spontaneous phase transition of hexagonal wurtzite CoO: application to electrochemical and photoelectrochemical water splitting

The addition of water initiates the phase transition of hexagonal CoO to Co(OH)2 nanocrystals. Inducing the phase transition of h-CoO on various substrates results in efficient chemical bonding between Co(OH)2 and the substrate. The efficient deposition of Co(OH)2 is widely applicable for electrochemical and photoelectrochemical water oxidation reactions.