Efficient aqueous activation of boron nitride colloidal catalysts for enhanced selective methane oxidation under mild conditions

Abstract

Non-metal hexagonal boron nitride (BN) catalysts hold significant promise for the selective oxidation of light alkanes due to their distinctive anti-overoxidation properties. Although reaction-induced BOx species are typically considered the active phase, their formation within the inert BN lattice often requires harsh activation conditions and high reaction temperatures, limiting the production of value-added liquid oxygenates at low temperatures. In this study, we demonstrate that active BOx species can be efficiently generated on boron nitride colloids (BNC) through a simple hydrothermal treatment at 140 degrees C in a clean aqueous environment. A combination of spectroscopic and microscopic investigations reveals that these BOx species develop at lattice-disordered boron sites along the edges of BN particles. Mechanistic studies, supported by theoretical calculations, indicate that BOx formation follows radical-driven pathways, facilitated by the simultaneous activation of H2O and O-2 on disordered boron species. By utilizing the activated BNC catalysts for low-temperature selective methane oxidation below 80 degrees C with H2O2 as a green oxidant, we achieved approximately four times higher C1 oxygenate productivity (31.7 mmol g(cat)(-1) h(-1)) compared to non-activated BNC, while maintaining high selectivity (>90%) and good reusability over 10 cycles.