Through a non-aqueous sol–gel method and a direct reduction in 5% H2-Ar in place of the gel calcination step, pure nickel nanoparticles with average diameter of 65 nm were synthesised. Studies in air and subsequent reduction were also performed with mixed results both phase and size wise. Under reducing atmosphere, temperature and dwelling time were found to be critical factors and with improvements mean diameters as low as 15 nm were obtained in combination with hexagonal carbon. Optimally nanoparticles of nickel are best prepared by direct reduction in hydrogen of the precursor gel at 400 °C for 8 hrs at 0.5 °C · min–1 This carbon-containing nano-sized nickel can be potential catalysts for fuel cells.
Petit, C. TG., Alsulaiman, M. SA., Lan, R., & Tao, S. (2012). Direct Synthesis of Ni Nanoparticles by a Non-Aqueous Sol–Gel Process. Nanoscience and Nanotechnology Letters, 4(2), 136-141. https://doi.org/10.1166/nnl.2012.1302