Ball-Milled Processed, Selective Fe/h-BN Nanocatalysts for CO₂ Hydrogenation

Fe/h-BN nanocatalysts were obtained by a combination of precipitation and high-energy ball-milling (HEBM) techniques. Mechanical treatment at a rate of 300 and 500 rpm induced defects in the h-BN lattice and led to the formation of iron nitride nanoparticles when processing at a higher ball-milling mode. Lewis base centers formed as a result of the interaction of h-BN surface defects with water vapor from ambient air led to an increase in the activity of the Fe/h-BN catalyst in the CO2 hydrogenation. Iron carbides, 2–4 nm in size, formed during the activation stage in the Fe/h-BN nanocomposites after HEBM increased the selectivity toward hydrocarbon formation. Calculations based on the density functional theory showed a significant weakening of the CO bond on the surface of iron carbide and suggested the iron nitride → iron carbide transformation as the most energetically favorable route.