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RESEARCH PRODUCT

Segregation of copper oxide on calcium copper titanate surface induced by Graphene Oxide for Water splitting applications

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Abstract Photoelectrochemical cells (PEC) are promising devices for hydrogen production via sunlight energy. One of the important challenges in this area is to design photoactive electrodes able to absorb visible light. A good photoelectrochemical behavior depends on the presence of surface active sites to photogenerate current at the lower possible potential for water splitting. Recent investigations in this field are focusing on perovskite materials such as CaCu3Ti4O12 (CCTO) as visible light active electrode due its outstanding structure in which CCTO encloses in its structure a visible light absorbance component (CuO). The presence CuO on the material surface is mainly responsible for trapping electrons. Therefore, CCTO photoelectrocatalysts were prepared using different amounts of graphene oxide (GO) in this work. Physico-chemical characterizations showed that the oxidation of GO at high temperatures lead to the reduction of Ti4+ to Ti3+ and Cu2+ to Cu+, causing a segregation of copper on grain boundaries regions as revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman characterizations. Electrochemical performance and materials resistivity are measured in dark and under visible light irradiation. CCTO prepared using 3% of GO showed 50% higher photocurrent generation and hydrogen generation rate than pure phase of CCTO.