Hexagonal boron nitride: A metal-free catalyst for deep oxidative desulfurization of fuel oils

Abstract

Oxidative desulfurization (ODS) has been proved to be an efficient strategy for the production of clean fuel oil. Numerous metal-based materials have been employed as excellent ODS catalysts, but being hindered by their high-cost and potential secondary pollution. In this work, we employed graphene analogous hexagonal boron nitride (h-BN) as a metal-free catalyst for ODS with hydrogen peroxide (H2O2) as the oxidant. The h-BN catalyst was characterized and proved to be a few-layered structure with relatively high specific surface areas. The h-BN catalyst showed a 99.4% of sulfur removal in fuel oil under the optimized reaction conditions. Besides, the h-BN can be recycled for 8 times without significant decrease in the catalytic performance. Detailed mechanism analysis found that it is the boron radicals in h-BN activated H2O2 to generate ·OH species, which can readily oxidize sulfides to corresponding sulfones for separation. This work would provide another choice in choosing metal-free catalysts for ODS.

Keywords

• Boron nitride
• Metal-free
• Oxidation
• Deep desulfurization
• Fuel oils