Using Density Functional Theory To Unravel the Size-Dependent Effect of Au Nanoparticles and Au Single Atoms Adsorbed on Carbon Nitride for the Hydrogenation of Nitrobenzene

Hydrogenation of nitrobenzene to aniline is extensively applied in the chemical and pharmaceutical industries, and exploring high-activity and environmentally friendly nanoscale catalysts remains a great challenge. Herein, we investigated the activity of Au(100) nanoparticles, Au single-atom catalysts, and Au cluster catalysts of different sizes anchored on C2N for the hydrogenation of nitrobenzene to aniline based on density functional theory. The results indicate that the Au single-atom catalyst shows excellent activity for nitrobenzene to aniline with an extremely low limiting potential (UL = −0.45 V). In addition, the hydrogenation mechanism of nitrobenzene on different sizes of Au catalysts is elucidated by electronic structure information and thermodynamics. This indicates that the high metal activity of the Au single-atom catalyst and the efficient desorption of aniline are essential as superior catalysts for hydrogenation of nitrobenzene to aniline. This work not only explores an efficient nanoscale catalyst for nitrobenzene hydrogenation but also provides an idea for tuning the size of transition metals to enhance catalytic capacity.