Formic acid formation via direct hydration reaction (CO + H2O → HCOOH) on magnesia-silver composite

Abstract

Formic acid provides broad range application with significant importance in pharmaceutical industry and chemical industry for producing many basic medicines and fine chemical products such as rubber and leather. Traditional synthesizing routes for generating formic acid involve toxic reactants, harsh reaction condition or low atomic efficiency. The commercial synthesizing strategy is also far from satisfactory, because of the poisonous waste fluid, non-recyclable byproduct and complicated separation processes. Herein we propose direct hydration reaction (CO + H2O → HCOOH) on magnesia-silver composite utilizing periodic Van der Waals density-functional calculations. The hydration reaction of carbon monoxide shows a small barrier 0.29 eV for obtaining the essential intermediate state *CO ⋯*OH. Formic acid production with water assistance at magnesia-silver composite shows an intermediate state, and energy barriers with small relative energies 0.17 eV and 0.188 eV. The thermodynamic and dynamic feasibility for water-assisted formic acid production at silver-supported magnesia film is verified by the calculations of equilibrium structures, adsorption energetics, Bader charge populations, differential charge densities, crystal orbital Hamilton populations and potential energy profiles. As far as we know, the direct hydration reaction of carbon monoxide for producing formic acid on oxide film has never been proposed before this contribution. It is anticipated that our results could provide useful clue for obtaining formic acid via direct hydration strategy on oxide-metal composite.