The effect of calcium doping oil the performance of Co/CcO(2) catalysts in ethanol steam reforming was examined using various characterization techniques including CO temperature-programmed reduction O-2 and CO pulse chemisorption, laser Raman spectroscopy, X-ray diffraction, isotopically labeled oxygen exchange, and diffuse reflectance infrared Fourier transform spectroscopy. Characterization results showed Ca incorporation to lead to oxygen vacancies and unit Cell expansion ill the ceria lattice. The creation of oxygen vacancies, in turn, enhanced the oxygen mobility in ceria-supported Co catalysts. Steady-state reaction studies showed increased Tor, and higher H-2 yields Over Co catalysts Supported on Ca-doped ceria in ethanol steam reforming.