Synthesis of Nickel Nanoparticles Supported on Nanoporous Silicon Oxycarbide (SiCO) Sheath−Core Fibers

Abstract

Nickel (Ni) nanoparticles with average diameters less than 5 nm were successfully synthesized on nanoporous silicon oxycarbide (SiCO) sheath−core fibers by incipient wetness impregnation of Ni acetylacetonate precursor followed by reduction at temperatures above 250 °C. The SiCO fibers were fabricated by pyrolyzing electrospun 5/15 PUS/PMMA composite fibers at temperatures from 250 to 1000 °C to contain nanoporous cores and striated sheaths. The SiCO fibers pyrolyzed up to 600 °C were superhydrophobic and became superhydrophilic when pyrolyzed at 800 °C and above. Such a drastic switch from superhydrophobicity to superhydrophilicity coincided with the disappearance of aliphatic methyl and methylene groups. The SiCO ceramic fibers pyrolyzed at 1000 °C were highly porous with BET surface area 95.7 m2/g, pore volume 0.352 cm3/g, and average pore size 26 nm. They were thermally and chemically stable enough to support the Ni acetylacetonate precursor to be reduced to Ni nanoparticles at 250, 500, and 900 °C. S...