Abstract
Asymmetric (Pt|Nafion|Pt-Pd-Cu) assemblies were fabricated to study the nitrate-reduction reaction (NRR) at the cathode surface. The influence of the material composition, supplied current, and applied potential on the reactivity, kinetics, and product selectivity were thoroughly investigated. The cathode assembly consisting of 54atom% Pt showed enhanced reactivity both in binary (Pt-Pd; k(1)approximate to 10.7x10(-3)min(-1)) and ternary (Cu-Pt-Pd; k(1)approximate to 28.6x10(-3)min(-1)) states. This composition was found to be highly nitrite-selective (80% in the binary state and 53% in the ternary state). The mechanistic studies revealed that the reduction of nitrate ions to ammonia proceeded through a catalytic hydrogenation reaction followed by electrochemical hydrogen generation.