Cu₂O/Cuコアシェルナノワイヤアレイによる太陽光水分解光電極の作製

抄録

In recent days, hydrogen is considered as an alternative energy which could instead of the fossil fuel in the future. A new clean method to manufacture hydrogen gas is called solar water splitting. Cu₂O is considered as a promising and attractive material for solar driven hydrogen production because the suitable band gap (ca. 2.0 eV) and the low cost. Based on the band gap, it can be calculated the maximum theoretical light-to-hydrogen conversion efficiency is 18% at AM 1.5 spectrum, and the theoretical photocurrent of 14.7 mA/cm². However, the experimental conversion efficiency was much lower than the theoretical one, due to self-corrosion coinciding with water-splitting reaction and that an electron and a hole activated by the sun light irradiation are easily recombined in oxidation film. In this research, Cu₂O/Cu core-shell Nanowire (NW) has been fabricated on the surface of the photoelectrode by the polycarbonate template method to increase the conversion efficiency by optimizing the NW structure. We have investigated the relationship between NW's structure and photocurrent density, as well as incident photo to current efficiency (IPCE). As a result, we find the optimum conditions of NW's diameter and oxidation time. The visible light responsiveness from IPCE results has also been confirmed.