Formic acid oxidation has been studied on bismuth modified Pt(1 1 1) electrodes in perchloric acid media using non-rotating and hanging meniscus rotating disk (HMRD) electrodes. On unmodified Pt(1 1 1) electrodes, the voltammetric profiles are controlled simultaneously by reaction paths going through the active intermediate and the poison (CO). For the Bi-Pt(1 1 1) electrodes, high oxidation currents are always obtained and poison formation is inhibited. Using HMRD electrodes in 0.1 M HClO4+0.05 M HCOOH, full kinetic control of the active intermediate reaction path can be achieved, and no accumulation of poison was detected. The Tafel slope for this process was also calculated, resulting in a value of 120 mV. With this value, a detailed mechanism for this path can be proposed, which coincides with that found in UHV environments. (C) 2003 Published by Elsevier B.V.