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

[Display omitted] • Edge-N-rich carbon nanosheet @ porous biochar (NCN@PB) was synthesized from waste biomass by self-assembly. • Hybrid structure and rich Edge-N contents led to the high exposure of "active sites" for H 2 S catalytic oxidation. • H 2 S molecule transfer and electron transfer were improved by the hybrid structure and active sites of NCN@PB. • H 2 S dissociation and O 2 activation were enhanced by Edge-N according to DFT and In-situ DRFITS. 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 H 2 S 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 H 2 S catalytic oxidation, i.e., H 2 S dissociation and O 2 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. [ABSTRACT FROM AUTHOR]