Nanoporous Anodic Bismuth Oxide Photo-Anodes

Bismuth oxide has widely been investigated for photo degradation of dyes for safeguarding the environment. However, not much work has been reported on bismuth oxide as a photo electrode material for solar water splitting. Bismuth oxide has well-dispersed valence bands that show enhanced mobility of charge carriers, high refractive index, and large dielectric constant. These properties are attractive for photo catalysis. Thin films of nanoporous bismuth oxide were synthesized by a simple electrochemical anodization of bismuth substrate. Annealing the anodic nanoporous Bi2O3 at 200 °C for 2 h resulted in stabilization of the metastable β-Bi2O3 phase at room temperature. A maximum photo current density of 0.97 mA/cm2 was observed for 10 V 30 min sample at an applied potential of 0.5 VAg/AgCl.