Synergistic effect of Pt single atoms, clusters and nanoparticles on carbon doping with nitrogen for highly efficient and selective hydrogenation of nitroaromatics

Abstract

This work constructs a series of Pt/NC catalysts with various Pt contents (0.22 wt%, 0.42 wt%, and 1.08 wt%) via the liquid-phase reduction method and their catalytic behaviors are systematically evaluated for heterogeneous catalytic hydrogenation of nitroarenes. The results show that 1.08% Pt/NC exhibits excellent catalytic performance: under quite mild conditions (30 °C, 1.0 MPa H₂), it can efficiently convert nitrophenol within just 3 min (90.2% conversion), with nitro-group hydrogenation selectivity >99% and a TOF of 5298.6 h⁻¹; moreover, it has an extremely ultra-high TOF of 74 191.8 h⁻¹ in the hydrogenation reaction of nitrobenzene to aniline, showing ultra-high intrinsic activity. Additionally, using nitrobenzene selective hydrogenation as a model reaction, the proposed reaction pathways are provided. Combined with spherical Aberration Corrected-Transmission Electron Microscope (AC-STEM) and XPS characterization studies, it can be known that Pt single atoms, clusters and nanoparticles are together loaded on the surface of nitrogen-doped carbon, and there is electron interaction between pyridinic nitrogen and Pt (electrons transferring from Pt to N). Compared with other catalysts, the electronic interaction between Pt and N in 1.08% Pt/NC is stronger, its adsorption capacity for hydrogen at Pt nanoparticles and clusters and the –NO₂ group at Pt single atoms via the interaction of “Pt^δ+⋯ON” is superior, and it can greatly enhance the activity and selectivity of nitro-group hydrogenation.