Manipulating the crystalline morphology and facet orientation of copper and copper-palladium nanocatalysts supported on stainless steel mesh with the aid of cationic surfactant to improve the electrochemical reduction of nitrate and N2 selectivity

Abstract

Surfactants, namely, cetyltrimethylammonium chloride, polydiallyldimethylammonium chloride, and benzethonium chloride were used to control the crystal growth of metallic Cu nanoparticles supported on stainless steel mesh electrodes as to improve the selective electrochemical conversion of NO3− to non-toxic N2. Results showed that the Cu(200)/Cu(111) ratio controlled the selectivity of N2, NO2−, and NH4+. The Kd value increased from 10% to 30% when the Cu(200)/Cu(111) intensity ratio was decreased 60% to 30%, meaning increase Cu(111) increased N2 production. Furthermore, the presence of a second metal, namely, Pd increased the N2 selectivity. The best N2 yield (XN2 = 22%), occurring on monometallic Cu, synthesized with BZT at 1-time CMC was further increased to XN2 = 65% over bimetallic Pd0.27Cu0.73/SS. The selectivity of nitrite (SNO2-) and ammonium (SNH4+) on Cu/SS were 33.1 and 43.5%, respectively, which were decreased to 0.30 and 34.0%, respectively, on bimetallic Pd0.27Cu0.73/SS.