A DFT Study on the Adsorption of Formic Acid and Its Oxidized Intermediates on (100) Facets of Pt, Au, Monolayer and Decorated Pt@Au Surfaces

Abstract

In this work we have systematically characterized the adsorption of formic acid, its decomposed intermediates and products on the (100) surfaces of Pt, Au, monolayer and decorated Pt@Au surfaces. The calculated thermodynamic results validate our previous experimental results that the decorated Pt@Au surface may facilitate formic acid oxidation compared with the benchmark Pt catalyst; while the monolayer Pt@Au surface is not suitable for formic acid oxidation.

Formic acid decomposition on Au catalysts: DFT, microkinetic modeling, and reaction kinetics experiments

“…The latter orientation was found to adsorb with practically zero BE on all three surfaces. HCOOH* binds to the three facets via its carbonyl O atom on a top site with the OH and CH bonds pointing toward and away from the surface, respectively, and has a BE of −0.10 eV (−0.15 eV), −0.16 eV (−0.19 eV), and −0.21 eV on Au(111), Au(100), and Au(211), respectively. Formate has long been proposed as one of the key reaction intermediates in FA decomposition and has also been frequently cited as a possible intermediate in WGS and methanol synthesis reactions.…”

“…This structural data is in agreement with the available experimental (NEXAFS and IR) and theoretical evidence. It has a BE of −1.69 eV (−1.82 eV), −2.02 eV (−2.10 eV), and −2.19 eV on Au(111), Au(100), and Au(211), respectively.…”

“…The BEs of atomic hydrogen on Au(111), Au(100), and Au(211) are −1.90 eV (−2.03 eV, −2.20 eV), −2.06 eV (−2.29 eV), and −2.11 eV (−2.32 eV), respectively. H* binds preferentially on the bridge sites on Au(100) and Au(211), and on the threefold sites on Au(111).…”

“…Carboxyl exhibits two stable adsorption configurations: (a) one with H pointing downward toward the surface, the trans isomer (COOH*) and (b) one with H pointing away from the surface, the cis isomer (COOHcis*). COOH* has a BE of −1.27 eV, −1.48 eV (−1.61 eV), and −1.58 eV on Au(111), Au(100), and Au(211), respectively. The formyl radical binds preferentially through its C atom to the top sites of all three Au facets, with BEs of −1.05 eV, −1.26 eV, and −1.38 eV on Au(111), Au(100), and Au(211), respectively.…”

Phase properties of carbon-supported platinum–gold nanoparticles for formic acid eletro-oxidation

“…Therefore, the Pt active sites of 600 C treated sample are not inhibited by intermediates (CO ads ). Yu and coworkers indicated that lattice contraction effect is beneficial for enhancing adsorption energies of HCOOH molecules onto the electrode surface, and promoting COOH with its H atom tilts downward towards the surface to make it very difficult to activate the CeH bond in HCOO to form the final product CO 2 afterwards [36]. Therefore, when the Pt 50 Au 50 /C catalyst was treated at 300e600 C, the catalytic activity was found to markedly increase with increasing treatment temperature, which could be attributed to lattice contraction effect.…”