Identifying the active sites in C-N codoped TiO2 electrode for electrocatalytic water oxidation to produce H2O2

摘要

Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material. For the two-electron water oxidation to produce H2O2, competitive reactions, including four- and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed, leading to great challenges to identify the real active sites on the electrode. In this work, Ti/TiO2-based electrodes calcined under air, nitrogen, or urea atmospheres were selected as electrocatalysts for two-electron water oxidation. Electrochemical analyses were applied to evaluate the catalytic activity and selectivity. The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy, while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering. The results demonstrated that Ti/TiO2 nanotube arrays served as the support, while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H2O2 production. This finding provided a new horizon to design efficient catalysts for H2O2 production.

关键词