The preparation of Ru nanoparticles supported on γ-Al 2 O 3 followed by chemical reduction using RuCl 3 as a precursor is demonstrated, and their properties are compared to Ru nanoparticles supported on γ-Al 2 O 3 prepared by impregnation of γ-Al 2 O 3 with Ru 3 (CO) 12 and subsequent thermal decomposition. The Ru nanoparticles resulting from chemical reduction of RuCl 3 are slightly larger (1.2 vs. 0.8 nm). In addition, Ru nanoparticles were deposited on Stöber SiO 2 using both deposition techniques. These particles were larger than the ones deposited on γ-Al 2 O 3 (2.5 and 3.4 nm for chemical reduction and thermal decomposition, respectively). Taking into account the size differences between the Ru nanoparticles, all catalysts display similar activity (0.14–0.63 mol·g Ru −1 ·h −1 ) and selectivity (≥99%) in the sunlight-powered Sabatier reaction. Ergo, the use of toxic and volatile Ru 3 (CO) 12 can be avoided, since catalysts prepared by chemical reduction of RuCl 3 display similar catalytic performance.