Regiochemically Oxo-functionalized Graphene, Guided by Defect Sites, as Catalyst for Oxygen Reduction to Hydrogen Peroxide.

Heteroatom-doped graphene attracted tremendous attention because of advanced electrocatalytic properties, for example, for oxygen reduction. However, the role of oxygen atoms as heteroatoms in graphene should be explored more deeply. Here, we used statistical Raman spectroscopy for single-layer material analysis and found that the regiochemistry close to vacancy defects plays a decisive role. Accordingly, defects possess a guiding effect on the introduction of oxygen functional groups close to those defect-sites. After the addition of oxo-groups close to vacancy defects, the activity and hydrogen peroxide (H2O2) selectivity of the material on hydrogen peroxide production improved significantly. The selectivity of H2O2 is above 84%, which is higher than the initial oxo-functionalized graphene and electrochemically reduced graphene. The half-wave potential is 0.73 VRHE, which is more positive than the initial oxo-functionalized graphene.