Catalytic activities of Pt thin films electrodeposited onto Bi coated glassy carbon substrate toward formic acid electrooxidation

Abstract

Catalytic activities of Pt thin films electrodeposited onto Bi coated glassy carbon substrate toward formic acid electrooxidation,

Correlation between Formic Acid Oxidation and Oxide Species on Pt(Bi)/GC and Pt/GC Electrode through the Effect of Forward Potential Scan Limit

“…Transition in the region with higher slope (II), that is, the region of irreversibly adsorbed oxygenated species, occurred ∼100 mV earlier on Pt(Bi)/GC electrode indicating a faster transformation of oxygenated species from reversible to irreversible state. Similar slope in the first region (I) is expected since there is an overlap in CVs up to 0.6 V [28]. For higher potentials, larger content of charge on Pt(Bi)/GC in relation to Pt/GC electrode brings about a steeper slope.…”

“…Platinum-bismuth deposits on glassy carbon (GC) substrate were prepared by a two-step process as described previously [28]. To recapitulate, Bi was deposited onto the GC from 2 mM Bi perchlorate in 0.1 M H 2 SO 4 using chronocoulometry at −0.1 V versus SCE.…”

“…The results are compared to Pt/GC treated in the same manner. Real surface area of the investigated electrodes was calculated from the charge of CO stripping, assuming 420 Ccm −2 for the CO monolayer [28].…”

“…Limit in Base Voltammograms. The bimetallic catalyst was prepared by a two-step process using chronocoulometry in a way that controlled the amount of Bi that was electrodeposited onto glassy carbon followed by electrodeposition of Pt layer [28]. Cyclic voltammetry revealed Bi leaching from the electrode surface indicating that Bi was not completely occluded by Pt.…”

“…It has been shown that a number of neighboring Pt sites on the electrode surface determine the reaction path in the sense that the dehydration path needs an ensemble of at least three adjacent Pt atoms, while the dehydrogenation path is possible on a smaller atomic ensemble [37]. The obtained behavior is explained primarily by the ensemble effect induced by surface Bi oxides interrupting Pt domains but to some extent could also be attributed to the influence of the underlying Bi onto the Pt surface layer, affecting the extent of poison adsorption on the Pt [28]. The results of the potentiodynamic measurements for HCOOH oxidation support the finding of the quasisteady-state measurements [28].…”