| 초록 |
Hydrogen evolution via water splitting in the photo-electrochemical cells is a clean technology. Recently a few groups have been studied dual photo-electrode system which is consisted of the n-type semiconductor photo-anode for water oxidation reaction and the p-type semiconductor photocathode for water reduction reaction. This system is having several advantages such as a without external bias for effective operation, a reducing on-set potential, a selectivity of reaction, a replacing counter electrode instead of Pt metal can reduce a cost compared with formal system which is semiconductor/metal which is specifically Pt. The CuO can be used as a p-type semiconductor due to its narrow band gap. However, it shows highly self-oxidation reaction by photo-excited electrons due to its reducing standard potential is located within its band gap. Ultimately self-oxidation of CuO reduce a faradaic efficiency of system. In this work, we demonstrate fabrication and analysis of RGO as a passivation layer coated CuO nanosheets on FTO glass substrate as a p-type photo-electrode. Morphology and microstructural properties of the RGO/CuO electrode was investigated by FE-SEM, XRD and HRTEM analysis. Photo-electrochemical properties were characterized by measuring photocurrents responses under both white and visible light illumination. The effect of passivation layer were also examined by measuring pulsed photocurrent versus elapsed time curve. By increasing thickness of RGO films, stability of CuO electrode were also increased. Furthermore, hydrogen evolution tests will be confirmed by using PEC cell with passivation layer coated CuO and as prepared TiO2 that can generate hydrogen and oxygen gases without external bias. |
