Co based N, S co-doped carbon hybrids for catalytic hydrogenation: Role of cobalt salt and doped S

Abstract

A series of Co-based N, S dual-doped carbon catalysts were prepared successfully via the pyrolysis of porous organic polymers (POPs) impregnated with cobalt salt and characterized by TEM, XRD, XPS, etc. The successful construction of cobalt-nitrogen (Co-Nx) sites is confirmed by XPS spectra. It was found that the content of Co-Nx sites is markedly affected by the type of cobalt salt, and the catalyst derived by the pyrolysis of the complex of POPs with Co(NO3)2·6H2O displays the best activity and outstanding selectivity for catalytic hydrogenation of various aromatic nitro compounds, it also demonstrates good recyclability. According to the results of control experiments, the activity for catalytic hydrogenation is mainly attributed to the Co-Nx sites. In addition, the doped S species in carbon shells can promote the formation of the active sites, which can effectively improve the performance of catalysts. Thus, this work can provide an effective and green approach for design highly effective transition metal-based multi-doped carbon catalysts with abundant metal-Nx sites.