Photoelectrocatalytic inactivation of Penicillium expansum spores on a Pt decorated TiO2/activated carbon fiber photoelectrode in an all-solid-state photoelectrochemical cell

Abstract

An electrode is fabricated using nanosized TiO2 on an activated carbon fiber initially ion sputtered by Pt (TiO2/ACF + Pt). An all-solid-state photoelectrochemical (ASPEC) cell using the electrode and a solid electrolyte is evaluated by photoinactivation of Penicillium expansum spores. The data analysis indicated that the Weibull model more accurately estimates the inactivation. The ASPEC cell shows a synergetic effect on the inactivation of the spores in the photoelectrocatalytic process with a 1log10 reduction time of the model rate constant of 4.37 × 10−3 min−1, with 3.87 × 10−3 and 4.49 × 10−4 min−1 for the photocatalytic and electrochemical processes, respectively. X-ray photoelectron spectroscopy shows that the Pt on the TiO2 of the electrode exists as metallic platinum, PtO and PtO2. The surface sensitization of TiO2 by PtO and PtO2 enhances the absorption of ultraviolet light. The enhanced charge separation was demonstrated by electrochemical impedance spectroscopy and transient photocurrent response. TiO2/ACF + Pt electrode illustrated more photoelectrocatalytic activity than the no Pt ion electrode. This synergetic effect could be attributed to the structures of the ASPEC cell and the interconnection with the separation of photogenerated electron-hole pairs under an electrical bias. The obtained results present a promising potential for the treatment of the spores in cold-storage environments.