N-type Cu₂O film for photocatalytic and photoelectrocatalytic processes: Its stability and inactivation of E. coli

Photoelectrocatalytic (PEC) inactivation of Escherichia coli K-12 by cuprous oxide (Cu₂O) film irradiated by visible light is firstly reported. A complete inactivation of about 7 log of E. coli was obtained for Cu₂O film within 6 h. The bacterial inactivation efficiency was significantly improved in a photoelectrochemical cell, in which 7 log of E. coli could be completely inactivated within 2 h by Cu₂O film with a 0.1 V bias. Electric charge transfer between electrodes and E. coli, and electric charge inactivation towards E. coli were investigated using membrane-separated reactor combined with short circuit photocurrent technique. H₂O₂, hole, and toxicity of Cu₂O film were found responsible for the inactivation of E. coli. Toxicity of copper ions (including Cu²⁺ and Cu⁺) leakage from Cu₂O films was determined and the results showed that the amount of leakage copper ions was not toxic to E. coli. Finally, the Cu₂O film was proved to be effective and reusable for PC and PEC inactivation of E. coli.