Titania-supported Pd-Cu bimetallic catalyst for the reduction of nitrite ions in drinking water

Titania-supported palladium-copper bimetallic catalysts (Pd-Cu/P25) are prepared by liquid-phase chemical reduction method and then applied in liquid-phase catalytic reduction of nitrite ions (NO2-). Compared with the conventional impregnation method, which usually needs a post-thermal reduction procedure to eliminate the introduced anions, liquid-phase chemical reduction at ambient temperature was proved to inhibit the aggregation of metal active components by means of TEM and DSC analysis in this work, and the catalyst exhibited superior catalytic activity. The conversion of nitrite reached a high level (1 × 10-4mol min-1gcat-1) and is about 14 times than that reported recently. The influences on the conversion of NO2-by support materials and the molar ratio of palladium to copper are also investigated, and further, the reaction mechanisms are discussed according to the characterization results of XPS and in situ FT-IR.