Phtotoelectrochemical water oxidation to H2O2 based on N-TiO2 derived from NH2-MIL-125 and in-situ application on degradation dye

Abstract

Electrochemical two-electron water oxidation reaction (2e− WOR) to produce H2O2 has been widely concerned. However, four-electron competition reaction causes the large overpotential and low production rates of 2e− WOR, which restrict its’ development and application. Herein, we prepared N-TiO2 derived from NH2-MIL-125 by the hydrothermal combined with calcination method. We found that N-TiO2 as photoanode exhibited the well properties of photoelectrocatalysis water oxidation, which gave an overpotential of 630 mV at 1 mA cm−2. The overpotentials of N-TiO2 was approximately 130 mV (at 1 mA cm−2) lower than NH2-MIL-125, and even lower than the previous reported TiO2, which may attribute to the increased oxygen vacancy with the calcination process and N doping. In addition, we investigated the degradation performance of the prepared catalysts to degrade methylene blue by photoelctrocatalysis on-site the preparation of H2O2. It was shown that N-TiO2 performed high degradation efficiency (∼91%) and excellent stability. The possible mechanism was speculated due to the increased oxygen vacancy and N doping. This work provides a new idea for photoelectrocatalysis water oxidation materials and points out a new way for on-site H2O2 production for direct use.