Super-high N-doping promoted formation of sulfur radicals for continuous catalytic oxidation of H2S over biomass derived activated carbon

Abstract

N-doped biomass derived activated carbon (NBAC) with superhigh content of surface N atom (17.2 at.%) and microchannel structure was prepared successfully via one-step pyrolysis method using supramolecular melamine cyanurate (MCA) as nitrogen source, and the breakthrough sulfur capacity was very high up to 1872 mg/g for catalytic oxidation of H2S under room temperature. The superhigh content of N atoms (17.2 at.%) provided massive active sites for the catalytic oxidation of H2S and formation of sulfur radicals which further helped the dissociation of H2S and O2, resulting in continuous catalytic oxidation of H2S over NBAC after the coverage of nitrogenous sites by multilayer sulfur. Moreover, the microchannel structure with enhanced mesopore volume promoted the mass transfer of reactants and emigration of product elemental sulfur to form multilayer sulfur. This work could provide an insight into the NBAC with superhigh N-doping content for continuous catalytic oxidation of H2S at room temperature.