Nitrate reduction in water: Influence of the addition of a second metal on the performances of the Pd/CeO2 catalyst

An attempt is made to improve the catalytic nitrate reduction on Pd/CeO2 catalysts by the addition of a second metal. The influence of the second metal such as Sn, In and Ag on the Pd/CeO2 for nitrate reduction is explored. The second metal is introduced over monometallic Pd/CeO2 by a redox reaction. Pd/CeO2 is more active than the bimetallic catalysts under pure hydrogen flow. Whereas in presence of CO2 the monometallic Pd/CeO2 is inactive for nitrate reduction, bimetallic catalysts are found to be more active than under pure hydrogen flow and also than the monometallic catalyst with a low selectivity towards ammonium ions, undesired product of the reaction. The Pd–Sn/CeO2 catalyst is comparatively the most suited for nitrate reduction.