Pro‐catalytic Role of Transition Metal/Metal Oxide Blend Low Pd Catalysts for Ethanol Oxidation: Diminution of Activation Energy and Promoting Electrode Kinetics at Low Temperature

Abstract

In this investigation the effect of temperature on catalytic oxidation of ethanol on multi‐metallic PdCoNi/C nano‐composite bearing reduced palladium loading, have been studied over the temperature range 20 °C to 80 °C. The structure, composition and surface morphology of the catalyst regime were determined through the respective techniques like XRD, EDX and TEM while electro‐catalytic parameters were evaluated by the help of voltammetry, chronoamperometry, impedance spectroscopy and ion‐chromatography. The apparent activation energies (Ea) of ethanol oxidation reaction (EOR) were drastically reduced over PdCoNi/C compared to Pd/C reflecting the energy efficiency of ternary matrix furnished with only 35 % Pd loading and the rest 65 % being cheaper transition metals. The long term poisoning rates warrant improved stability of PdCoNi/C and also figure out the robustness of the catalyst even at 20 °C. The Ea value is remarkably reduced, rendering appreciable mass activity in terms of current density per mg of Pd at each of the temperatures studied. The incorporation of transition metals Co and Ni onto Pd becomes particularly effective in orienting the EOR proceed through carbonate pathway as reflected by the columbic efficiency in terms of oxidation product yield ~5 times higher, compared to single Pd catalyst throughout the temperature range.