Two-step catalytic dehydrogenation of formic acid to CO2 via formaldehyde

Formic acid has been decomposed into hydrogen and carbon dioxide through a two-step process involving the formation of formaldehyde. This allows the formation of carbon dioxide and hydrogen in two different steps, negating the need for gas separation. A novel system for the catalytic disproportionation of formic acid into formaldehyde and carbon dioxide was thus far developed using monoclinic bismuth chromate hydroxide protocatalyst, m-Bi(OH)CrO4. The catalytically active species, BiCrO4, was isolated and its activity assessed for thermal disproportionation of formic acid under mild conditions (200 -300 degrees C, tube furnace). A maximum formaldehyde production rate of 0.065 mmol/mmol catalyst/hour was observed using bismuth chromate at 250 degrees C. The formaldehyde produced through this method was selectively dehydrogenated to formate by an IrCl3 catalyst at room temperature under basic conditions, with a dehydrogenation rate of 20.1 mmol of hydrogen/mmole catalyst/hour. This completes a step-by-step and yet efficient cycle of formic acid dehydrogenation. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.