Oxidation Mechanism of Formic Acid on the Bismuth Adatom-Modified Pt(111) Surface

Abstract

In order to improve catalytic processes, elucidation of reaction mechanisms is essential. Here, supported by a combination of experimental and computational results, the oxidation mechanism of formic acid on Pt(111) electrodes modified by the incorporation of bismuth adatoms is revealed. In the proposed model, formic acid is first physisorbed on bismuth and then deprotonated and chemisorbed in formate form, also on bismuth, from which configuration the C−H bond is cleaved, on a neighbor Pt site, yielding CO 2 . It was found computationally that the activation energy for the C−H bond cleavage step is negligible, which was also verified experimentally.

On the activation energy of the formic acid oxidation reaction on platinum electrodes

“…In order to get insight in to the oxidation mechanism, extensive DFT calculations have been carried out using well defined surfaces [12][13][14][15]. In these studies, different intermediates and reaction schemes have been proposed.…”

Peculiarities in the electrocatalytic behavior of ultralow platinum deposits on gold synthesized by galvanic displacement

“…6) currents turned out to be very low (due to accumulation of chemisorption products, first of all, СО ads ) and, the more so, insufficiently reproducible to be used for correct comparison of the activity of Pt n 0 Au at different n. Figure 7 shows anodic CVA branches for Pt n 0 Au (curves 1-3) and pc Pt electrodes in solution of 0.5 М НСООН + 0.5 М Н 2 SO 4 . It is known [6,7,29,30,52] that currents below ~ 0.60 V are…”

“…Since the 60s of the last century up to nowadays, the electrooxidation of HCO compounds (small organic molecules) was always in the focus of attention of scientists [1][2][3][4][5][6][7][8]. First of all this is associated with the fuel cell problem.…”

“…Among numerous chemical and electrochemical methods proposed for modifying the Pt catalyst surface, the method of galvanic displacement (GD) (also called galvanic replacement, spontaneous deposition, surface-limited redox deposition) [17,[21][22][23][24][25] shows the best promise. In this method, adatoms of the less electropositive non-noble metal ( [3,[6][7][8]28] and by the interaction by adsorbed species with adsorbed oxygen (probably, in the form of ОН ads ) for MOR [1, 2,5]. There are also differences in the composition of adsorbed species both weakly bound and SCS [2,[5][6][7]22].…”

“…In this method, adatoms of the less electropositive non-noble metal ( [3,[6][7][8]28] and by the interaction by adsorbed species with adsorbed oxygen (probably, in the form of ОН ads ) for MOR [1, 2,5]. There are also differences in the composition of adsorbed species both weakly bound and SCS [2,[5][6][7]22].…”