Enhancing the oxidative desulfurization efficiency of cobalt-loaded-porous carbon catalyst via nitrogen doping on carbon support

Abstract

Melamine (M)-incorporated bimetallic (Zn/Co)-azolate framework-6s (M( x )@BM6s) (with wide M-contents) composites were firstly synthesized via an in-situ method and used as a precursor to derive Co/N-enriched porous carbon (M( x )@BMC6s) via pyrolysis. Very small Co-nanoparticles (4–10 nm) uniformly distributed on highly porous carbon with much N-doping were obtained from M( x )@BM6s. The developed Co-based materials with high N-content were used as catalysts for heterogeneous oxidative desulfurization (ODS) of liquid model fuel, critical for the environment and the petroleum industry . M( x )@BMC6s (with various N-contents), especially the M( 10 )@BMC6 (obtained from M( 10 )@BM6 with 10% M), were more competitive in ODS than orther tested Co-based catalysts (without or with less N-sites) and comparable to the reported catalysts to date. For example, the turnover frequency of M( 10 )@BMC6 was 61.1 h ˗1 and ∼10 times that of Co/activated carbon. Additionally, the good reactivity of M( 10 )@BMC6 with adequate reusability might be understood by the good dispersion of small Co-nanoparticles. Importantly, dominant role of the doped N-species on carbon, by enhancing the synergy between Co- and N-species, was firstly suggested in this study. Finally, incorporation of N-sites in the carbon support for Co-nanoparticles can enhance the ODS performance, thus being suggested as an effective way to develop oxidation catalysts with outstanding performance. • Melamine incorporated bimetallic-azolate framework-6s were firstly prepared. • Co-nanoparticles well dispersed on N-enriched carbon were prepared from melamine/MOF. • Oxidative desulfurization (ODS) activity was increased by N-dopant on the carbon support. • The reusable M( 10 )@BMC6 had ∼ 10 times that of Co/activated carbon in ODS. • ODS reaction was explained with the facile formation of ⋅OH or 1 O 2 because of Co and N.