In one embodiment, a method for depositing a conductive material on a substrate is provided which includes exposing a substrate containing a barrier layer to a volatile reducing precursor to form a reducing layer during a soak process, exposing the reducing layer to a catalytic-metal precursor to deposit a catalytic metal-containing layer on the barrier layer, and depositing a conductive layer (e.g., copper) on the catalytic metal-containing layer. The volatile reducing precursor may include phosphine, diborane, silane, a plasma thereof, or a combination thereof and be exposed to the substrate for a time period within a range from about 1 second to about 30 seconds during the soak process. The catalytic metal-containing layer may contain ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, silver, or copper. In one example, the catalytic metal-containing layer is deposited by a vapor deposition process utilizing ruthenium tetroxide formed by an in situ process.