Photocatalytic Water-Splitting Characteristic of Electric Reduced Black TiO$_{\mathrm{2}}$ Nanorods

In various reduction methods of TiO$_{\mathrm{2}}$, the electric reduction could apply to anodized TiO$_{\mathrm{2}}$ nanotube. However, it is not suitable to reduce TiO$_{\mathrm{2}}$ nanorods(NRs) grown on fluorine doped tin oxide (FTO) substrate using hydrothermal method, because those are easily peeled off due to lattice mismatching between FTO and TiO$_{\mathrm{2}}$ NRs. In this talk, we will demonstrate electric reduced-black TiO$_{\mathrm{2}}$ NRs with strong adhesion on FTO substrate for an effective visible photocatalyst. To fabricate the reduced-black TiO$_{\mathrm{2}}$ NRs, we firstly deposited TiO$_{\mathrm{2}}$ seed layer on FTO glass using RF-sputtering for mitigating the exfoliation, then grow TiO$_{\mathrm{2\thinspace }}$NRs with hydrothermal method. Finally, TiO$_{\mathrm{2}}$ NRs were reduced with electric bias. The final reduced-black TiO$_{\mathrm{2}}$ NRs exhibit a higher photocurrent density, 0.9 mA/cm$^{\mathrm{2}}$ in comparison with pure-TiO$_{\mathrm{2}}$ NRs. This result indicates that our reduced-black TiO$_{\mathrm{2}}$ NRs has lower bandgap with modified valance band position and enhance the surface reactivity with oxygen defect generation.