Selective Formic Acid Dehydrogenation on Pt-Cu Single-Atom Alloys

Formic acid is a potential hydrogen storage molecule which dehydrogenates to form CO2 and H2 on metal surfaces. However, it can also decompose via a competing dehydration reaction that forms CO and H2O, reducing the amount of H2 produced and poisoning the catalyst with CO. Formic acid re-formation to hydrogen is typically performed by Pt and Pd catalysts, which while highly active for dehydrogenation also catalyze dehydration. Cu is typically not utilized, as it requires prohibitively high temperatures, although Cu surfaces are very selective toward dehydrogenation. We studied the reaction of formic acid on single-atom alloys (SAAs), consisting of single Pt atoms substituted into a Cu lattice. Surface science studies allowed us to relate alloy structure to reactivity and selectivity and visualize reaction intermediates. These experiments revealed that SAAs are able to selectively dehydrogenate formic acid with a 6-fold increase in yield in comparison to Cu. This increase in conversion is due to a more fac...