Two step synthesis of TiO2eCo3O4composite forefficient oxygen evolution reaction

For an active hydrogen gas generation through water dissociation, the sluggish oxygenevolution reaction (OER) kinetics due to large overpotential is a main hindrance. Herein, asimple approach is used to produce composite material based on TiO2/Co3O4for efficientOER and overpotential is linearly reduced with increasing amount of TiO2. The scanningelectron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) investigations reveal the wire like morphology of composite materials, formed by the self-assembly of nanoparticles. The titania nanoparticles were homogenously distributed onthe larger Co3O4nanoparticles. The powder x-ray diffraction revealed a tetragonal phase ofTiO2and the cubic phase of Co3O4in the composite materials. Composite samples withincreasing TiO2content were obtained (18%, 33%, 41% and 65% wt.). Among the compos-ites, cobalt oxide-titanium oxide with the highest TiO2content (CT-20) possesses thelowest overpotential for OER with a Tafel slope of 60 mV dec1and an exchange currentdensity of 2.98103A/cm2. The CT-20 is highly durable for 45 h at different currentdensities of 10, 20 and 30 mA/cm2. Electrochemical impedance spectroscopy (EIS)confirmed the fast charge transport for the CT-20 sample, which potentially acceleratedthe OER kinetics. These results based on a two-step methodology for the synthesis of TiO2/Co3O4material can be useful and interesting for various energy storage and energy con-version systems.