A new synthetic route has been developed to anchor a large amount of Pd nanoparticles (NPs) on the surface of hydrazinegrafted and (3-glycidyloxypropyl)trimethoxysilane-coated inorganic host particles such as Fe₃O₄ and SiO₂. The hydrazinegrafted inorganic particles reduce Pd²⁺ ions spontaneously under ambient conditions. This results in the production of Pd⁰ seeds and their nucleation, which leads to the growth of Pd NPs on the surface of the host particle itself. These anchored Pd NPs on Fe₃O₄ and SiO₂ have been characterized by elemental analysis, microscopy, and elemental mapping. Spherical Pd NPs of ≈ 0.3 and 1 nm are formed uniformly on Fe₃O₄ (25 nm) and SiO₂ (100 nm) particles, respectively. Their concentration on the host particles was 12 mg g^-1 for Fe₃O₄ and 20 mg g^-1 for SiO₂. These host particles loaded with Pd NPs have been investigated for their catalytic activity in the reduction of representative oxymetal ions such as UO₂²⁺ and Cr₂O₇^2- ions with formic acid. NP-loaded SiO₂ exhibited a good catalytic activity in both these reductions, whereas Pd NPs on Fe₃O₄ could reduce Cr₂O₇ ^2- ions only.