A new Pd/Al2O3-La2O3 catalyst has been synthesized for the reduction of NO with hydrogen. This catalyst is more active than coprecipitated Pd/Al2O3 catalysts. The revealed effect of the improvement of the catalytic activity at medium temperature and the increase of NH3 formation at high temperatures for Pd catalyst supported on alumina-lanthana prepared by the sol-gel method are ascribed to a new lanthanum-containing phase observed by X-ray powder diffraction and high resolution electron microscopy. (C)2000 Elsevier Science B.V. All rights reserved.