Abstract
Photoelectrochemical water splitting under visible light has attracted attention for renewable hydrogen production. Despite prevalent investigations, many challenges still hindered an efficient energy conversion, such as enhancing the reaction efficiency in visible light. Thus controlling the photoelectrode materials is an essential step in designing new materials for water splitting. CaCu3Ti4O12 (CCTO) has received great attention as photocatalyst under solar light due to its combined band gap as result of the presence in its structure of TiO2 active in UV light and CuO active under visible light. In this work, a cubic CCTO with different amount of exfoliated hexagonal boron nitride has been synthesized. The produced materials were fully characterized. Physico-chemical characterizations demonstrate that bore and nitrogen co-doped CCTO causes an increase in grain boundaries thickness, and thus leads to shift peaks in XRD and Raman spectra. UV–Vis diffuse reflectance spectroscopy showed a decrease of the bang gap value after adding boron nitride nanosheets into CCTO. The electrochemical performance and the resistivity of the obtained materials were performed using electrochemical impedance spectroscopy in dark and under visible light exposition. The onset potential recorded for CCTO with 3% of boron nitride nanosheets (Eg = 2.9), is around 0.5 V and the current generation is 16 times more than pure phase of CCTO. This work shows that CCTO with 3% of boron nitride nanosheets can be considered as an active photoelectrocatalyst under visible light irradiation for water splitting. Hydrogen production measurements show that the rate of H2 production reached arround 8.1 µmol/h under visible light after adding 3% of BN nanosheets to CCTO which presents 16 times increase in comparison with pure CCTO.