Scale-Up Biomass Pathway to Cobalt Single-Site Catalysts Anchored on N-Doped Porous Carbon Nanobelt with Ultrahigh Surface Area

Porous CoNC catalysts with ultrahigh surface area are highly required for catalytic reactions. Here, a scale-up method to synthesize gram-quantities of isolated Co single-site catalysts anchored on N-doped porous carbon nanobelt (Co-ISA/CNB) by pyrolysis of biomass-derived chitosan is reported. The usage of ZnCl2 and CoCl2 salts as effective activation-graphitization agents can introduce a porous belt-like nanostructure with ultrahigh specific surface area (2513 m(2) g(-1)) and high graphitization degree. Spherical aberration correction electron microscopy and X-ray absorption fine structure analysis reveal that Co species are present as isolated single sites and stabilized by nitrogen in CoN4 structure. All these characters make Co-ISA/CNB an efficient catalyst for selective oxidation of aromatic alkanes at room temperature. For oxidation of ethylbenzene, the Co-ISA/CNB catalysts yield a conversion up to 98% with 99% selectivity, while Co nanoparticles are inert. Density functional theory calculations reveal that the generated Co=O centers on isolated Co single sites are responsible for the excellent catalytic efficiency.