Effect of textual features and surface properties of activated carbon on the production of hydrogen peroxide from hydroxylamine oxidation

Herein, the textural features and surface properties of activated carbon were mediated by oxidation in the gas-phase or liquid-phase. Activated carbon (AC) treated by gas-phase oxidation showed greatly enhanced production of hydrogen peroxide (H2O2) via hydroxylamine oxidation primarily because of the formation of more surface quinoid species. The yield and selectivity of H2O2 increased to 55% and 87%, respectively, which were much superior to those of the parent AC catalyst. Detailed structural and surface analyses revealed that gas-phase oxidation produced more quinoid but less carboxylic groups on activated carbon, and the opposite effect was observed for the samples treated by liquid-phase oxidation; this confirmed the crucial role of the quinoid groups on AC. Quantitative correlation of the relationship between the activity and the number of the surface quinoid groups further indicated the critical role of the quinoid groups, serving as intrinsic active species.