Highly ordered TiO2 nanotube array (TiNT), possessing highly ordered and vertically oriented tube arrays structure and super-hydrophilic property, is suitable to confine metal nanoparticles with a wetting chemistry method. In this work, the relationship between the metal loading amount and the concentration of metal precursor solution was developed. Making use of this relationship, the loading amount can be predicted and controlled beforehand. Highly uniform Ru and Ag nanoparticles dispersed into TiO2 nanotube array were respectively obtained by a simple ultrasonic-aided incipient wetness impregnation method. The Ag amount of Ag/TiNT determined by inductively coupled plasma agrees well with the theoretical prediction. A narrow Ru nanoparticle size range of 1-6 nm with an average value of 4 nm was calculated from Ru(1 wt%)/TiNT. Finally, the Ru/TiNT was successfully applied to the combination reaction of carbon dioxide reforming and partial oxidation of methane. (C) 2011 Elsevier B.V. All rights reserved.