We report a density functional theory (DFT) study of microscopic detailed effects of the bonding configuration of nitrogen-doped graphene (N-graphene) within the carbon lattice (including pyridinic, pyrrolic, and graphitic N) on the reactivity and mechanistic processes of H2O2 reduction reaction. We simulated the adsorption process of H2O2, analyzed the mechanistic processes, and calculated the reversible potential of each reaction step of the H2O2 reduction reaction on N-graphene. The results indicate that the adsorption of H2O2 on the pristine and N-doped graphene surfaces occurs via physisorption without the formation of a chemical bond. When H(+) is introduced into the system, a series of reactions can occur, including the breakage of the O-O bond, the formation of an O-C chemical bond between oxygen and graphene, and the creation of water molecules. The results also indicate a decrease in the energy of the system and a positive reversible potential for each reaction step. The calculations of the relative energy of each reaction step and the value of the onset potential for H2O2 reduction reaction suggest that the reactivity of pristine and N-doped graphene has the following order: pyridinic N-graphene > pyrrolic N-graphene > graphitic N-graphene > pristine graphene. We also proposed an explanation based on electrostatic potential calculations for this dependence of the reactivity order on the bond configuration of the doping in N-graphene. The results of this study should help in the atomic-scale understanding of the dependence of the reactivity of N-graphene on its microstructure, inspire the study of various types of heteroatom-doped graphenes to improve their catalytic efficiency, and provide a theoretical framework to analyze their reactivities.

The selectivity of molecular oxygen activation on the exfoliated graphitic carbon nitride (g-C 3 N 4 ) and its influence on the photocatalytic phenol degradation process were demonstrated. Compared with bulk g-C 3 N 4 , the exfoliated nanosheet yielded a 3-fold enhancement in photocatalytic phenol degradation. ROS trapping experiments demonstrated that although the direct hole oxidation was mainly responsible for phenol photodegradation on both g-C 3 N 4 catalysts, molecular oxygen activation processes on their surface greatly influenced the whole phenol degradation efficiency. Reactive oxygen species and Raman spectroscopy measurements revealed that oxygen was preferentially reduced to ·O 2 − by one-electron transfer on bulk g-C 3 N 4 , while on g-C 3 N 4 nanosheet the production of H 2 O 2 via a two-electron transfer process was favored due to the rapid formation of surface-stabilized 1,4-endoperoxide. The latter process not only promotes the separation of photogenerated electron−hole pairs but also greatly facilitates reactive oxygen species formation and subsequently enhances phenol degradation.

Nearly atomic precise Au25/NixAl-LDH catalysts obtained via adsorption of Au25Capt18 onto predispersed NixAl-LDH following proper calcination show extraordinary alcohol oxidation property due to ultrafine Au cluster, ordered LDH layer and strong Au25–LDH synergy.

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