Nano-fibers of palladium-copper (Pd/Cu) in ceria for water-gas-shift (WGS) catalysis were prepared by electrospinning solutions containing polyvinylpyrrolidone (PVP) and soluble salts of cerium, palladium, and copper in a water/ethanol co-solvent. Catalyst precursors were mixed in a single pot, electrospun, and calcined to produce ceramic fibers with 88 wt% CeO2, 2% Pd, and 10% Cu. Slowing the rate of polymer removal with controlled heating during calcining did not significantly change fiber diameters (similar to 200 nm) but did lower the ceria crystallite to typically less than 10 nm and produce longer fibers that formed non-woven mats with structural integrity. The resulting catalyst materials were characterized for WGS activity by temperature-programmed and time-on-stream reactor tests. X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy analysis indicated that for different precursor salts, much of the Cu and Pd are incorporated into the ceria lattice before testing. For the Pd/Cu/ceria nano-fiber catalysts, time-on-stream testing at 400 degrees C showed high WGS activity, that asymptotically decayed with time. Post-testing XPS and Raman spectroscopy indicated that reduced Pd and Cu segregate to the surface during time-on-stream testing, which lowers activity. Exposure to intermittent oxidizing environments, particularly with O-2, partially reverses the metal segregation and restores catalyst activity. Adding surfactant to the synthesis solution increases catalyst surface area without significantly improving activity or slowing its asymptotic decay, which suggests that activity is not limited strictly by surface area, but rather by metal/ceria interactions, for these catalysts. (C) 2014 Elsevier B.V. All rights reserved.