The Effect Of A P-N TiO2/Cu2O/ITO Composite Junction Using E-Beam Evaporation On A Shewanella Oniedensis MR-1 Microbial Coupled Photoelectrochemical Cell

Krishna Gorrepati

Abstract

Microbial fuel cells (MFCs) show promise as a renewable energy source that can generate electricity through microbes but suffer from low power densities. A photocathode or photoelectrochemical cell is proposed to be substituted with the cathodic electrode in a MFC to create a microbial photoelectrochemical cell (MPC). It was hypothesized that a TiO2/Cu2O/ITO composite photocathode in a MPC would have greater voltage outputs when compared to those of a plain ITO cathodic electrode in a MFC. The stability of TiO2 with the wide absorption spectrum of Cu2O would increase efficiency because the composite band gap setup correlates to an npn transistor. Moreover, under photoirradiation, the photocathode generates electron hole pairs to make the cathode potential higher than that of the anode, thus increasing the voltage output. Forty trials and thirty trials were conducted for the Plain ITO glass control MFCs and the TiO2/Cu2O/ITO composite MPCs respectively. In each trial, the voltage output was collected every minute for one week. Once the bacteria had stabilized, the mean for each trial was calculated. Using a two­-sample t-­Test with the means, the results indicated that control MFCs and MPCs were significantly different: t(51)=13.33, p <0.001. The MPCs provided a 335% increase in voltage outputs when compared to those of the control MFCs and had greater Q1, median, mean, and Q3 values. Based off the results, a scalable single cell MPC prototype was produced that could generate electricity using waste from wastewater plants. As the power density of MPCs continue to increase, they can eventually become a scalable and reliable form of green energy.

 
Apr 10th, 12:00 AM

The Effect Of A P-N TiO2/Cu2O/ITO Composite Junction Using E-Beam Evaporation On A Shewanella Oniedensis MR-1 Microbial Coupled Photoelectrochemical Cell

Microbial fuel cells (MFCs) show promise as a renewable energy source that can generate electricity through microbes but suffer from low power densities. A photocathode or photoelectrochemical cell is proposed to be substituted with the cathodic electrode in a MFC to create a microbial photoelectrochemical cell (MPC). It was hypothesized that a TiO2/Cu2O/ITO composite photocathode in a MPC would have greater voltage outputs when compared to those of a plain ITO cathodic electrode in a MFC. The stability of TiO2 with the wide absorption spectrum of Cu2O would increase efficiency because the composite band gap setup correlates to an npn transistor. Moreover, under photoirradiation, the photocathode generates electron hole pairs to make the cathode potential higher than that of the anode, thus increasing the voltage output. Forty trials and thirty trials were conducted for the Plain ITO glass control MFCs and the TiO2/Cu2O/ITO composite MPCs respectively. In each trial, the voltage output was collected every minute for one week. Once the bacteria had stabilized, the mean for each trial was calculated. Using a two­-sample t-­Test with the means, the results indicated that control MFCs and MPCs were significantly different: t(51)=13.33, p <0.001. The MPCs provided a 335% increase in voltage outputs when compared to those of the control MFCs and had greater Q1, median, mean, and Q3 values. Based off the results, a scalable single cell MPC prototype was produced that could generate electricity using waste from wastewater plants. As the power density of MPCs continue to increase, they can eventually become a scalable and reliable form of green energy.