NCQD-induced nitrogen configuration engineering for constructing hybrid CN with exceptionally high nitrogen content and predominantly pyrrolic/pyridinic-N for catalytic hydrogenation

Abstract

Integrating nitrogen is beneficial for increasing defect sites and enhancing catalytic performance and has been a persistent research focus in the structural construction of carbon materials. Nevertheless, the uncontrollable distribution and intricate bonding reactions of nitrogen species within the carbon matrix have posed challenges in precisely regulating nitrogen type and content. Herein, nitrogen-doped carbon quantum dots (NCQDs) served as inhibitors to hinder the generation of graphitic nitrogen with weak electronegativity, thereby facilitating nitrogen configuration engineering. The NCQDs interacted with dicyandiamide to inhibit the polycondensation reaction between triazine units during the carbonization process, thereby synthesizing a porous hybrid carbon with exceptionally high nitrogen content (36.71 at%) and a pyrrolic/pyridinic-N percentage of 90.9 at%. Such high nitrogen content, along with edge nitrogen proportions, was unprecedented compared to conventional methods. As confirmed by experimental characterization and DFT calculations, abundant edge pyrrolic/pyridinic-N atoms facilitated charge transfer, which strengthened the interaction with Pt nanoparticles (NPs) and increased the electron density at the Fermi level, thereby improving the adsorption of the composites to reactants. This work presents an ideal strategy for the development of carbon-based catalysts with high nitrogen content and for studying nitrogen configuration in catalysis.