PHOTOELECTROCHEMICAL ANALYSIS OF TITANIUM DIOXIDE BY USING OXALIC ACID AS A SACRIFICIAL DONOR

Abstract

Photoelectrochemical (PEC) water splitting is a very promising green method to produce solar fuel. Titanium dioxide (TiO2) has been widely used as photocatalyst for this type of reaction. Improving the performance of TiO2 for PEC water splitting has been ongoing and addition of sacrificial donor especially from waste is an attractive option to achieve this. Oxalic acid is one component in organic waste stream that can be used as sacrificial donor. The TiO2 thin films has been fabricated by coating TiO2 paste on Fluorine Tin oxide (FTO) glass surface. The morphology of the TiO2 thin films were porous and rough with uniform particles size with crystallite size of about 20 nm and dominant anatase peak. The TiO2 photoelectrode undergo PEC testing to measure its photolectroactivity by using oxalic acid as a sacrificial donor in two different type of electrolytes which are distilled water and sodium sulfate (NA2SO4) aqueous solution. The photocurrent produced without addition of oxalic acid is much lower than with the acid. The saturation photocurrent for aqueous NA2SO4 solution and water electrolyte is 0.1 mA/cm2 and negligible respectively. While the photocurrent for addition of oxalic acid in NA2SO4 aqueous solution is 0.5 mA/cm2 and the photocurrent for oxalic acid in water only is 0.9 mA/cm2, which is almost double compared to in NA2SO4 and tenfold in water only. The highest photocurrent produced by TiO2 photoelectrode is by addition of oxalic acid in aqueous (H2O) electrolyte.