New carbon composites containing ultrafine Fe, Co, or Ni particles. 1. Facile synthesis by pyrolysis of organometallic polymers

Abstract

Uniformly dispersed, air-stable carbon composites containing ultrafine α-Fe, Co, or Ni particles were obtained by a careful two-step thermal degradation of a copolymer of acrylonitrile (AN) and 2,4-hexadienyl-[tri(carbonyl)iron] acrylate. Carbonization yields were 45–55% and metal particle size ranged from 80 to 120 nm. Analogous degradation of the acrylonitrile copolymer with CoCl₂(AN)₂, CoCl₂(4-vinylpyridine)₂, or Ni(bis-styrene carboxylate) gave similar composites containing β-Co (18 nm), β-Co (55 nm), or cubic Ni (52 nm) particles, respectively, with lower carbonization yields. Other salient features noted for the metal-containing composites are progressive graphitization promoted by catalysis of nascent metal species at low temperature, microporous structures with surface areas of 75 and 55 m² g⁻¹ for Co and Ni composites, respectively, high electrical conductivities (10–10² S cm⁻¹), ferromagnetism, and catalysis in the decomposition of H₂O₂.