The American University in Cairo,
Keywords: water splitting, hollow spheres, co-catalyst, graphene, impedance
Summary:The main challenge hindering the development of efficient solar fuel cell systems is the identification of robust, cost-effective, and abundant catalysts. Herein, we demonstrate the ability to synthesize photoactive, relatively cheap and abundant catalyst for the solar-assisted water splitting. The proposed catalyst is a composite of Co-Cu/graphene immobilized on hierarchical hollow mesoporous Titania. Diffuse Reflectance analysis showed visible light absorption for (Co-Cu) 2%-TiO2/RGO with an estimated band gap of 2.41 eV, as compared to 3.13 eV for Titania. Photoluminescence spectra showed a significant decreasing in recombination rate of the photogenerated electron-hole pair for (Co-Cu) 2%-TiO2/ RGO nanocomposites. Upon their use as photoanodes in solar fuel cells, the fabricated nanocomposites show a 14-fold increase in photocurrent density compared to Titania. This enhancement was confirmed via the measurement of electron and phonon lifetimes. The results attained in this study demonstrate a step toward using non-precious co-catalysts to boost the performance of photocatalysts in solar fuel cells.