Promoting Effect of Hydrocarbon Impurities on the Electro-Oxidation of Formic Acid at Pt Nanoparticles Modified GC Electrodes

This paper addresses a systematic study of the unexpected enhancement of some hydrocarbon impurities towards formic acid oxidation (FAO) at Pt nanoparticles modified GC electrode, for the first time. That is, the oxidation current peak observed at ca. 0.25 V (assigned for the direct FAO to CO2,Ip(d)) increases in the presence of a minute amount (similar to ppm range) of Acetonitrile > Acrylonitrile > Acetamide > Pyridine vinyl acetate > Pyrrole > Methyl Acrylate > toluene with a concurrent decrease of the second oxidation peak current (assigned for the indirect oxidation of FA, I-p(ind)) observed at ca. 0.65 V. Moreover, the onset potential of FAO is favored by shifted towards the negative potentials together with a noticeable increase of the stability of the current transients measured during FAO in the presence of impurities. The enhanced activity is believed to originate from interrupting the contiguity of Pt sites by the pre-adsorption of the respective impurity at nano-Pt surface thus impedes/weakens the adsorption of the poisoning CO. (C) 2015 Elsevier Ltd. All rights reserved.