Syntheses of nano-sized cubic phase early transition metal carbides from metal chlorides and n-butyllithium

Abstract

Nano-sized early transition metal carbides, including TiC, ZrC, HfC, V₄C₃, NbC and TaC, were synthesized from colloidal precursors generated by reducing the metal chlorides, TiCl₄, ZrCl₄, HfCl₄, VCl₃, NbCl₅, and TaCl₅, respectively, with n-C₄H₉Li in hexane. The colloids were formed from the reduction of the metal centers, which then nucleated into nano-scaled metal clusters. The major byproducts were LiCl, C₄H₁₀, and C₄H₈, indicating that the butyl groups probably underwent β-hydrogen elimination and reductive elimination. This suggests that C–C bond activation of the butyl groups was in operation, leaving residual carbon atoms in the metal colloids. The colloids were further heated at 873–1273 K to crystallize into cubic phase TiC, ZrC, HfC, V₄C₃, NbC and TaC nanoparticles.