Selective Electrocatalytic Water Oxidation to Produce H₂O₂ Using a C,N Codoped TiO₂ Electrode in an Acidic Electrolyte

Production of hydrogen peroxide (H₂O₂) via in situ electrochemical water oxidation possesses great potential applications in the energy and environment fields. In this work, for the first time, we reported a C,N codoped TiO₂ electrode for selective electrocatalytic water oxidation to produce H₂O₂ in an acidic electrolyte. An electrochemical anodic oxidation method combined with postcalcination in the presence of urea was applied to fabricate such a C,N codoped TiO₂ electrode, which was evidenced by detail structural characterizations. The calcination temperature and urea atmosphere were found to play key roles in its 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 0.29 μmol L^-1 cm^-2 h^-1. More importantly, a simple recalcination strategy was developed to recover the deactivation electrode. This study proposed an efficient C,N codoped TiO₂ electrode toward water oxidation to selectively produce H₂O₂ in the acidic electrolyte, which could be further used to in situ generate H₂O₂ for the energy- and environment-related fields with water as the precursor.