We have developed a new green method for deposition of silver nanoparticles (Ag NPs) on TiO2. Insoluble solid silver oxalate (Ag2C2O4) is dissolved in an aqueous solution of N,N-dimethyl-1,3-diaminopropane. The alkylamine-activated silver oxalate undergoes TiO2-catalyzed thermal decomposition at low temperatures (<100 degrees C), leading to high-yield conversion to Ag NPs (>90%). The catalytic activity of the prepared Ag NPs on the TiO2 is evaluated via hydrogenation of 4-nitrophenol.