n-p/n photoelectrode, solar hydrogen, water splitting, heterojunction
In this study, a photoelectrolysis cell based on multilayered TiO2/Ni/CuO (M-cell) photoelectrode is prepared on ITO substrate (110 nm thick) using a multi-target direct current and radio-frequency magnetron sputtering technique in which Ni acts as a ohmic contact. One can see that the XRD patterns of M-cell are polycrystalline with preferable diffraction peaks at about 2θ=32.4° and 35.6°, corresponding to the (110) and (111) planes of CuO along with two preferential peaks at 2θ=25.3° and 38.8° of the TiO2 anatase phase, as shown in Fig. 1. Other phases, such as Cu2O and Cu, are hardly traced in the samples, which has somehow detrimental effect on photoelectrocatalytic (PEC) property of the sample. The M-cell electrode, characterized by cyclic voltammograms, shows a rapid increase in the current density of about 0.27 mA cm-2 at 0.3 V vs. SCE, while the sputtered mono TiO2/ITO electrode (560 nm thick) exihits a satuated current density of about 0.20 mA cm-2 at 0.0 V vs. SCE. This is attibutable to a better alignment of the flat bend potential between the oxide layers. Thus, we can expect that the M-cell can deliver a higher hydrogen evolution rate under solar illumination.