Selective Electrocatalytic Water Oxidation to Produce H2O2 Using a C, N Co-doped TiO2 Electrode in Acidic Electrolyte.

Abstract

Production of hydrogen peroxide (H2O2) via in-situ electrochemical water oxidation possesses great potential applications in the energy and environmental fields. In this work, for the first time, we reported a C, N co-doped TiO2 electrode for selective electrocatalytic water oxidation to produce H2O2 in acidic electrolyte. An electrochemical anodic oxidation method combined with post-calcination in the presence of urea was applied to fabricate such C, N co-doped TiO2 electrode, which was evidenced by detail structure characterizations. The calcination temperature and urea atmosphere were found to play key roles in their catalytic performances, the optimized 600N sample exhibited an onset potential of 2.66 V (vs Ag/AgCl) and a Tafel slope of 51 mV dec-1 at pH=3. Under the optimal applied potential, the cumulative H2O2 concentration for this sample reached to 0.29 umol L-1 cm-2 h-1. More importantly, a simple re-calcination strategy was developed to recover the deactivation electrode. This study proposed an efficient C, N co-doped TiO2 electrode toward water oxidation to selectively produce H2O2 in acidic electrolyte, which could be further used to in-situ generate H2O2 for the energy and environment related fields with water as precursor.