Atomic-Level Understanding for the Enhanced Generation of Hydrogen Peroxide by the Introduction of an Aryl Amino Group in Polymeric Carbon Nitrides

Heterogeneous catalysts are often “black boxes” due to the insufficient understanding of the detailed mechanisms at the catalytic sites. An atomic-level elucidation of the processes taking place in those regions is, thus, mandatory to produce robust and selective heterogeneous catalysts. We have improved the description of the whole reactive scenario for polymeric carbon nitrides (PCN) by combining atomic-level characterizations with magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy, classical reactive molecular dynamics (RMD) simulations, and quantum chemistry (QC) calculations. We disclose the structure–property relationships of an ad hoc modified PCN by inserting an aryl amino group that turned out to be very efficient for the production of H 2 O 2 . The main advancement of this work is the development of a difluoromethylene-substituted aryl amino PCN to generate H 2 O 2 at a rate of 2.0 mM·h –1 under the irradiation of household blue LEDs and the identification of possible active catalytic sites with the aid of 15 N and 19 F MAS solid-state NMR without using any expensive labeling reagent. RMD simulations and QC calculations confirm and further extend the experimental descriptions by revealing the role and locations of the identified functionalities, namely, NH linkers, −NH 2 terminal groups, and difluoromethylene units, reactants, and products.