Preparing highly active and stable non-noble-metal-based dry reforming catalysts remains a challenge today. In this context, supported nickel nanoparticles with sizes of 1.3 +/- 0.2 and 2.1 +/- 0.2 nm were synthesized on silica and ceria, respectively, via a two-step colloidal approach. First, 2-nm nickel silicide colloids were synthesized from Ni(COD)(2) and octylsilane at low temperature; they were subsequently dispersed onto supports prior to reduction under H-2. The resulting catalysts display high activity in dry reforming compared to their analogues prepared using conventional approaches, ceria providing greatly improved catalyst stability.