Ni@onion-like carbon and Co@amorphous carbon: control of carbon structures by metal ion species in MOFs

Abstract

We first report the facile synthesis of metal–carbon composites consisting of metal nanoparticles (NPs) and different types of carbon species: onion-like and amorphous carbon, Ni@onion-like carbon and Co@amorphous carbon. By simply changing the metal species in an isostructural metal–organic framework, thermal decompositions of MOF-74 directly afforded different types of metal NPs and carbon composites, which exhibited good electrical conductivity. In particular, the Ni@onion-like carbon, having a well-ordered carbon structure, had high electrical conductivity (σ = 5.3 Ω⁻¹ cm⁻¹ at 295 K), explained by a modified model of the Efros–Shklovskii variable range hopping.