PtN3-Embedded graphene as an efficient catalyst for electrochemical reduction of nitrobenzene to aniline: a theoretical study

The electrochemical reduction of nitrobenzene (NBER) holds great promise for not only removing toxic pollutants, but also producing valuable aniline, in which the development of catalysts with high-efficiency still remains a huge challenge. In this work, by means of density functional theory (DFT) computations, we proposed several single transition metal (TM) atoms embedded into the single vacancy of graphene with nitrogen-doping (TMN3/G, TM = Ni, Cu, Pd, and Pt) as the catalysts for NBER. Our results revealed that, among these candidates, PtN3/G is the most active catalyst for the NBER due to its smallest limiting potential (−0.21 V), in which the hydrogenation of Ph-NO2* to Ph-NOOH* is identified as the potential-determining step. Compared with other catalysts, the strongest binding strength of Ph-NOOH* with PtN3/G is responsible for its superior catalytic activity towards NBER, which can be deeply understood on the basis of the corresponding electronic structure analysis. Thus, PtN3/G is a quite promising single-atom-catalyst with high efficiency for nitrobenzene reduction, which provides a rational paradigm for converting harmful nitrobenzene to valuable aniline under ambient conditions.