Towards highly exposed active sites via Edge-N-rich carbon nanosheet @ porous biochar for efficient H2S catalytic oxidation

Abstract

In this study, Edge-N-rich carbon nanosheet @ porous biochar (NCN@PB) was synthesized successfully from waste biomass self-assembly in a simple and green approach. The accessible and efficient utilization of edge-N enriched on the surface, together with the hybrid structure of NCN@PB improved the H2S oxidation capacity up to 390.1 mg/g at room temperature, reflecting an 8-fold enhancement compared with the blank biochar. The Density functional theory calculation, in-situ DRIFTS, and the characterization results further uncovered the desulfurization mechanism of active sites. Edge-N species decreased the barriers in critical steps governing H2S catalytic oxidation, i.e., H2S dissociation and O2 activation, especially the pyrrolic N. This strategy is beneficial for the development of surface engineering on metal-free catalysts and provides a new idea for improving the catalytic combustion activity of N-doped biochar.