Nitrate reduction in water catalysed by Pd–Cu on different supports

Screening tests were carried out in order to study the influence of the support in the performance of Pd monometallic and Pd–Cu bimetallic catalysts for the reduction of nitrate in water. Several metal oxides, as well as metal oxides and activated carbon or carbon nanotube composites were assessed as supports. The catalysts were prepared and tested under the same operation conditions. It was observed that supports play an important role in the catalytic performance and in some cases are directly involved in the reaction mechanism. The Pd–Cu catalysts supported on titanium dioxide and on the composite containing carbon nanotubes and titanium dioxide present the highest conversions, while those supported on ceria materials are the most selective to nitrogen.

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► The support plays a key role in the catalytic performance in nitrate reduction.
► In some cases the support is directly involved in the reaction mechanism.
► Pd–Cu catalysts supported on TiO2 and CNT–TiO2 present the highest conversions.
► The catalysts supported on ceria are very selective to nitrogen.
► Activated carbon is a good support with intermediate activity and nitrogen selectivity.