Degrading organic pollutants and generating electricity in a dual-chamber rotating-disk photocatalytic fuel cell (RPFC) with a TiO2 nanotube array anode

Abstract

This work reports a dual-chamber photocatalytic reactor with a TiO2 nanotube array (TNA) rotating-disk electrode to treat organic pollutants. The TNA was prepared using electrochemical anodization on the surface of a Ti rotating-disk electrode in ethylene glycol solution containing 0.3 wt% NH4F and 2 wt% H2O. The TNA rotating-disk electrode was employed as a photoanode. This reactor actually functioned as a fuel cell because it was able to generate and output electricity through degradation, or “burning,” of organic pollutants. Compared with conventional photocatalytic reactors, the proposed dual-chamber reactor with the TNA anode features improved light utilization efficiency and better hole–electron separation and mass transfer. Another important new characteristic of this reactor is that organic pollutants were degraded not only by photocatalytic degradation but also by additional oxidation provided by electrochemically generated H2O2 and ·OH in the system, resulting in superior overall performance. This is the first rotating-disk photocatalytic fuel cell realizing degradation of organic pollutants through multiple oxidation pathways with simultaneous generation of usable electricity.