Decomposition of formic acid via carboxyl mechanism on the graphene nanosheet decorated by Cr, Mn, Fe, Co, Ni, Pd, Ag, and Cd metals: A DFT study

The carboxyl mechanism of formic acid decomposition was investigated on the graphene nanosheet decorated with 8 single metal atoms from the thermodynamics and kinetics point of view using DFT computations. The thermodynamic results showed that for all metal-doped graphene surfaces, the adsorption of studied entities in the gas phase was more favorable compared to the solution phase. The Mn-doped graphene surface was more suitable for the adsorption of studied entities than the other surfaces. Adsorption of CO as a poisoning entity was also more favored on Mn-doped graphene with the highest adsorption energy of-47.56 kJ/mol while the Pd and Co samples were less poisoned with CO intermediate. Our kinetic studies demonstrated that the C-H bond activation was the rate-determining step of formic acid decomposition for all of the examined systems in the gas and solution phases. Additionally, formic acid decomposition was kinetically more suitable on the Mn-doped graphene nanosheet with the lowest activation energy of 73.19 kJ/mol.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The carboxyl mechanism of formic acid decomposition on graphene nanosheets decorated with single metal atoms was investigated using DFT computations. The thermodynamic results showed that gas-phase adsorption was more favorable than solution-phase adsorption on all metal-doped graphene surfaces, with Mn-doped graphene being the most suitable. CO adsorption was favored on Mn-doped graphene with the highest adsorption energy. Kinetic studies revealed that the rate-determining step of formic acid decomposition was C-H bond activation for both gas and solution phases, with Mn-doped graphene showing the lowest activation energy.