FABRICATION OF n-TiO_2 THIN FILMS BY SPD AND ELECTROOXIDATION METHODS FOR EFFICIENT PHOTOSPLITTING OF WATER

摘要

Thin films of n-TiO_2 were synthesized by spray pyrolytic deposition (SPD) and electrooxidation methods. The optimum conditions for SPD samples were found to be substrate temperature of 450℃, spray time of 100 seconds, spray solution concentration of 0.20 M, carrier gas pressure of 20 pounds per square inch (psi). The optimum conditions for the samples made by electrooxidation were found to be 1.2 mA cm_(-2) applied current density, electrooxidation time of 20 kilo seconds in 5 M KOH solution and sintering time of 15 minutes at 750℃. The maximum photoconversion efficiency was found to be 4.54 % for SPD samples at applied potential, E_(app) of 0.467 V compared to that of 1.08 % at applied potential, of 0.693 V for the f sample made by electrooxidation. The corresponding photocurrent densities were 2.38 mA cm~(-2) for SPD samples and 0.8 mA cm~(-2) for the sample made by electrooxidation at light intensity of 40 mW cm~(-2).. The electrode potential at open circuit, E_(aoc) were found to be -1.167 V/SCE and - 1.093 V/SCE for the samples prepared by SPD and electrooxidation methods respectively under I illumination of light of intensity 40 mW cm~(-2).