Complex PtPdRh nanoparticles: Synthesis, characterization, and performance in the electrocatalytic oxidation of ammonia

This study elucidates the electrocatalytic oxidation (ECO) of ammonia (NH3) over a complex PtPdRh nanoparticle electrocatalytic material immersed in a 0.5-M H2SO4 solution, where the electrolyte was measured using a linear sweep voltammogram (LSV) technique. The complex PtPdRh nanoparticle electrode was synthesized from H2PtCl6, Pd(NO3)3 and Rh(NO3)3 and deposited on an alumina substrate to improve the NH3-ECO ability. The experimental data indicate that a high ECO activity was achieved during the catalytic oxidation over the PtPdRh electrocatalytic material when using a high potential sweep rate; the maximum current density reached for the NH3 oxidation was 0.4 mA in the voltage range of 0.1 V. Interesting, this LSV oxidation ability may explain the significant activity of the catalyst in an acidic environment. The catalyst structure was characterized by polarization curves, UV–vis, three-dimensional excitation–emission fluorescent matrix (EEFM) spectroscopy and TEM. EEFM was applied to evaluate the fresh catalyst yields for the fluorescent plots of 220/345 nm and 210/385 nm, and TEM determined the particle size of the nanoparticles and indicated a high dispersion phenomenon had occurred.

Graphical abstractLinear sweep voltammograms (LSV) display greater oxidation current density for the PtPdRh electrocatalyst through the presence of a shoulder at approximately 0.1 V and 0.4 mA; this wide peak represents the current density reached during NH3 oxidation reaction. This oxidation ability may explain the significant activity of the catalyst, due to the more electrochemically active sites formed during the process.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The electrocatalytic oxidation of ammonia over a complex PtPdRh material. ► The complex PtPdRh material exhibits significant activity in an acidic environment. ► The nanoscale complex PtPdRh material displayed a high dispersion phenomenon.