Electrochemical Promotion of Bimetallic Palladium‐Cobalt Nano‐Catalysts for Complete Methane Oxidation

Abstract

The catalytic activity and electrochemical promotion of catalysis (EPOC) of the bimetallic Pd‐Co nanoparticles (10 nm) deposited on yttria‐stabilized zirconia were investigated for complete methane oxidation. The reaction was conducted under open‐circuit and under polarization in a temperature range of 320‐400°C in reducing, stoichiometric, and oxidizing conditions. The catalytic activity of the catalyst nanoparticles increased to 40% upon positive polarization in all gaseous compositions. A comparison of three reaction conditions revealed that the highest reaction rate increase (enhancement ratio, ρ = 1.4) occurs under reducing conditions. The reaction rate increased upon anodic polarization resulted in non‐Faradaic electrochemical modification of catalytic activity (𝛬 >> 1) in reducing and oxidizing conditions and Faradaic or electrochemical enhancement (𝛬 < 1) in stoichiometric reaction conditions. This work demonstrates that the formation of different Pd and Co oxide phases can be accurately controlled by electrochemical stimuli and, in reducing conditions, result in pseudo‐capacitor behaviour.