Abstract: The present invention provides technology for controlling, or tuning, the catalytic activity of gold provided upon nanoporous supports such as those derived from nanoparticulate titania. It has been discovered that the nature of the surfaces of the nanoparticles used to support a nano-metal catalyst, such as catalytically active gold, has a profound effect upon the catalytic properties of the supported catalyst. The support surface may be altered as desired to control the activity of the gold. The present invention teaches how thermal treatment of nanoparticulate media incorporated into a nanoporous support prior to deposition of catalytically active gold dramatically suppresses the ability of a resultant catalyst system to oxidize hydrogen. Yet, the system still readily oxidizes CO.