The hydrogenation properties of Ti-V hydrides coated with nanoparticles have been studied in gaseous mixtures of argon and hydrogen with and without additions of 1% CO. Nanoparticles of Pd, Ni, and co-deposited Pd/Pt with particle sizes of ~30–60 nm were formed by electroless deposition on the hydride surfaces. The alloy resistance to CO could be significantly improved by particle deposition. Large amounts of hydrogen were absorbed in a CO-containing gas when Ni and Pd/Pt deposition had been applied, while pure Pd deposition had no positive effect. Ni was found to have a stronger effect than those of Pd/Pt and Pd, possibly because of the size effect of Ni nanoparticles. The hydrogenation properties of Ti-V hydrides coated with nanoparticles have been studied in gaseous mixtures of argon and hydrogen with and without addition of 1% CO. Nanoparticles of Pd, Ni, and co-deposited Pd / Pt with particle sizes of ~ 30- 60 nm were formed by electroless deposition on the hydride surfaces. The large amounts of hydrogen were absorbed in a CO-containing gas when Ni and Pd / Pt deposition had been applied, while pure Pd was deposited with no positive effect. Ni was found to have a stronger effect than those of Pd / Pt and Pd, possibly because of the size effect of Ni nanoparticles.