Summarizing the addition even of small amounts of Rh xA

From the calculated Tafel slopes (slope = 2.303RT/αFn) the electrons involved in the rate determining step can be estimated [68].
It should be noted that, in the current work, the estimated Tafel slopes (Table 4) are homologues very high (in comparison with the value of 120 mV decade−1), due to the high overpotential. The high overpotential may attributed to mass transport phenomena [71].