Defect enriched N-doped carbon nanoflakes as robust carbocatalysts for H ₂S selective oxidation

Abstract

The rational designed defect enriched N-doped nanocarbons present superior activity and stability for H ₂S selective oxidation.

Abstract

Nanocarbons have emerged as low-cost, efficient and durable nonmetallic catalysts for H ₂S selective oxidation. However, the most efficient active sites for H ₂S activation remain elusive, which restricts further development of high-performance catalysts for industrial application. Herein, we report on the synthesis of N-doped carbon nanoflakes with tunable nitrogen dopants and abundant structural defects for H ₂S selective oxidation. These defect enriched N-doped carbon nanoflakes exhibited significantly enhanced catalytic performance (>740 g _sulfur kg _cat. ⁻¹ h ⁻¹), stability (>110 h) and decent tolerance to impurity gas (CO ₂) and steam toward continuous H ₂S selective oxidation. Combined advanced characterization, control experiments and theoretical simulation showed that the N species along with defects on N-doped carbon nanoflakes could enhance significantly the catalytic activity, and further confirmed that the pyridinic N was the most active species and the C atoms adjacent to N atoms exhibit strong interaction with HS ⁻. Our study provides predictive guidelines for the rational design of highly efficient and durable carbocatalysts for continuous catalytic oxidative desulfurization.