Single Co Atom Catalyst Derived from Terpolymer Pyrolysis for Hydrogenation of Nitroarenes

Abstract

Recently, single atom catalysts (SACs) with isolated metal atom as the active site have received extensive attention for their excellent catalytic performance. However, limited by the strong aggregation tendency of monometallic atoms, the construction of SACs remains a formidable challenge. Herein, we developed a facile ternary copolymerization-pyrolysis approach to synthesize a single cobalt atom catalyst (Co₁@NC) by employing amino-functionalized cobalt phthalocyanine (CoPc(NH₂)₄) as the metal precursor. Specially, CoPc(NH₂)₄ was copolymerized with melamine and 1,4-phthalaldehyde to yield a terpolymer, thereby allowing CoPc to be more uniformly and stably distributed in the polymer network. Subsequently, the obtained terpolymer was pyrolyzed to afford Co₁@NC. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) and X-ray absorption spectroscopy (XAS) directly confirmed that the catalyst Co₁@NC was a single cobalt atom catalyst. Furthermore, the large specific surface area (S_BET = 418.8 m²/g) and high cobalt content (2.71 wt%) of Co₁@NC provided more cobalt active sites and therefore displayed excellent catalytic activity in the hydrogenation of nitrobenzene. In addition, the catalyst showed remarkable cyclic stability in five cycles and remained as the single atom catalyst.