Electrocatalytic Reduction of Nitrate over Palladium Nanoparticle Catalysts: A Temperature-Dependent Study

Abstract

The electrocatalytic reduction of nitrate in over carbon-supported palladium nanoparticles (mean size ) was studied with differential electrochemical mass spectrometry (DEMS) as a function of reaction temperature between 0 and . The palladium nanoparticles are active for the electrocatalytic reduction of nitrate as evidenced by the detection of and NO in DEMS. NO is produced during the anodic scan between 0.8 and vs reversible hydrogen electrode (RHE) and also during the cathodic scan between 0.3 and vs RHE. In contrast, is only produced during the cathodic scan between 0.4 and vs RHE. While the reduction of to NO and during the cathodic scan occurs only at significant overpotentials, the required overpotential decreases with increasing temperature. The potential dependencies of the apparent activation energies for the cathodic NO and production indicate that at potentials above 0.1 and vs RHE, the respective kinetics of NO and evolution are primarily determined by the potential. At potentials below 0.1 and vs RHE, respectively, the apparent activation energies for the evolution of NO and are largely potential independent.