Fabrication and Characterization of Pd-TNPs Bimetallic Nanoelectrode for Electrochemical Denitrification from Groundwater

A novel Pd-TNPs (Palladium-TiO2 Nanopores) bimetallic nanoelectrode was developed to improve the removal rate of nitrate by electrochemical method. The Pd-TNPs bimetallic nanoelectrode was fabricated by plating Pd on TiO2 nanopores. In the Pd-TNPs bimetallic nanoelectrode, Ti nanostructure can increase the specific surface area, meanwhile Pd nanoparticles can raise ratio of nitrogen to hydrogen and present high activity for nitrate reduction. According to scanning electron microscope(SEM), the PdTNPs bimetallic nanoelectrode is a porous morphology with lamellar deposit on it. Elements on the surface of Pd-TNPS bimetallic electrode were observed by energy-dispersive X-ray spectroscopy(EDS), Ti, Pd and 0 respectively. Using the Pd-TNPs bimetallic nanoelectrode, nitrate removal efficiency achieved 91.7% in the presence of 0.50 g/L Na2SO4 after 90 min electrolysis. The Pd-TNPs nanoelectrode exhibited higher nitrate reduction rate, under the same current conditions, the removal rate of the Pd-TNPs bimetallic nanoelectrode was 224.6% compared with that of the Ti nanoelectrode. Nitrate could be completely removed using the Pt anode in the presence of 0.5 g/L NaCl, and with little amount of ammonia and almost no nitrite detected in the treated solution. For the same initial nitrate concentration, the nitrate removal rate increased sharply with increasing current density. (C) 2018 The Electrochemical Society.