Photon flux influence on photoelectrochemical water treatment

This work quantifies the role of incident light in photoelectrochemical water treatment device efficiency to destroy waterborne pollutants. The conversion of incident photon flux from monochromatic light emitting diodes (285 nm, 300 nm, and 365 nm) into current (i.e., incident photon-to-current efficiency, IPCE) was studied. Identical photocurrent responses were obtained at identical photon flux but using different monochromatic wavelengths. Photocurrent increased with higher incident photon flux from the light emitting diodes (LEDs). However, an exponential decrease in IPCE occurred simultaneously, indicating a lower percentage of those photons converted into electrons. Higher photocurrents indicated more charge carriers photoelectrogenerated greater amount of oxidant species (e.g., center dot OH) capable of degrading organic pollutants in water. Thus, IPCE aided in optimizing the energy needed to generate center dot OH and remove pollutants.