Mass transport studies at rotating cylinder electrode (RCE): Influence of using plates and concentric cylinder as counter electrodes

This study shows the effect of using four-plate, six-plate and concentric cylinder as counter electrodes on the RCE mass transport characterization. The Cu(II)/Cu(0) process in sulfuric acid is employed as the model reaction. Based on the analysis of Sh = aRebSc0.356 correlation, the values of the constant a, associated with shape and cell dimensions, were 0.012, 0.014, and 0.022 for the four-plate, six-plate and concentric cylinder, respectively. This behavior suggests that both, the shape and area of the counter electrode, influence the values of a. The values of b, associated with the hydrodynamic regime, were similar for the six-plate and the concentric counter electrodes, b = 0.91; whereas for the four-plate counter electrode, b = 0.95. The fact that the four-plate device gives greater values of b suggests that this device has a higher turbulence-promoting action than the others. The mass transport at the RCE with four plates has a performance similar to the concentric counter electrode, which is important from the technical and economics standpoints.