Electro-Oxidation of Ammonia at Novel Ag2O−PrO2/γ-Al2O3 Catalysts

Abstract

An Ag2O(x)−PrO2(y)/γ-Al2O3 electrocatalyst series (X:Y is for Ag:Pr from 0 to 10) was synthesized, to use synthesized samples in electrochemical applications, a step in fuel cells advancements. Ag2O(x)−PrO2(y)/γ-Al2O3/Glassy-Carbon was investigated for electrochemical oxidation of ammonia in alkaline medium and proved to be highly effective, having high potential utility, as compared to commonly used Pt-based electrocatalysts. In this study, gamma alumina as catalytic support was synthesized via precipitation method, and stoichiometric wt/wt.% compositions of Ag2O−PrO2 were loaded on γ-Al2O3 by co-impregnation method. The desired phase of γ-Al2O3 and supported nanocatalysts was obtained after heat treatment at 800 and 600 °C, respectively. The successful loadings of Ag2O−PrO2 nanocatalysts on surface of γ-Al2O3 was determined by X-rays diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR), and energy dispersive analysis (EDX). The nano-sized domain of the sample powders sustained with particle sizes was calculated via XRD and scanning electron microscopy (SEM). The surface morphology and elemental compositions were examined by SEM, transmission electron microscopy (TEM) and EDX. The conductive and electron-transferring nature was investigated by cyclic voltammetry and electrochemical impedance (EIS). Cyclic voltammetric profiles were observed, and respective kinetic and thermodynamic parameters were calculated, which showed that these synthesized materials are potential catalysts for ammonia electro-oxidation. Ag2O(6)−PrO2(4)/γ-Al2O3 proved to be the most proficient catalyst among all the members of the series, having greater diffusion coefficient, heterogeneous rate constant and lesser Gibbs free energy for this system. The catalytic activity of these electrocatalysts is revealed from electrochemical studies which reflected their potentiality as electrode material in direct ammonia fuel cell technology for energy production.

Electro-Oxidation of Ammonia over Copper Oxide Impregnated γ-Al2O3 Nanocatalysts

“…Moreover, quite similar ammonia oxidation voltammograms are reported earlier, describing it as a three-electron process [72]. The D NH3 using all the catalysts can be estimated from the slope of the Randles-Sevcik (i p vs. υ 1/2 ) plot at a constant scan rate (100 mV•s −1 ) at 25 • C [73]. Resultantly, 16%-CuO/γ-Al 2 O 3 gives the highest value of the diffusion coefficient as compared to the other materials Ni/Pt [65] and Ni/Ni(OH) 2 [18], as enlisted in Table 3.…”

Photocatalytic and Biological Activity of ZnO Nanoparticles Using Honey

“…There were no other impurities observed. The average crystallite size of the synthesized ZnO nanoparticles was calculated from XRD data employing the Scherrer formula presented in Equation (1) [30].…”

Synthesis of Cr doped LiMnPO 4 cathode materials and investigation of their dielectric properties

“…Materials were mixed with KBr, then ground to smooth powders, and pressed into a disk. 49 All measurements were taken in a range of 400-4000 cm À1 . Comparative FTIR analysis of synthesized LiCr x Mn 1Àx PO 4 (x = 0.00, 0.03, 0.06, 0.1) is shown in Figure 5.…”