Improvement in Photocatalytic Effects of Dye Sensitized Titanium Dioxide by Hydroxyapatite Coating

Abstract

Applying photocatalytic n-semiconductor effect of titanium dioxide, performance of TiO₂ anode with copper oxides cathode as a wet solar cell in seawater is being studied. This research aimed to study photocatalytic effects of dye sensitized TiO₂ electrode coated by hydroxyapatite (HAp). TiO₂ electrode was manufactured double layered by screen printing method and copper oxides electrode by vacuum deposition on Type 329J4L stainless steel base substrate. N719 Ruthenizer dye was used for sensitizing on TiO₂ electrode and HAp was coated on the electrode surface by squeegee printing method. Four types of TiO₂ electrodes were studied; TiO₂ electrode, dye-sensitized TiO₂, HAp coated TiO₂, and dye-sensitized TiO₂ with HAp coating. Cell voltage and current density was measured under irradiated and dark conditions. The power densities of electrode with HAp coating was found higher than other electrodes without HAp. The current flow was enhanced by introducing HAp coating while dye sensitizing reduced current flow.  Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) analysis were performed. EIS analysis showed HAp coating increased capacitance values of each electrodes.  The surface of electrodes analysed by Scanning Electron Microscope (SEM) and Electron Dispersion X-ray Spectroscopy (EDS) indicated that HAp was dispersed on TiO₂ surface but was not formed as a layer.