Enhanced hydrogen selectivity from catalytic decomposition of formic acid over FeZnIr nanocatalyst at room temperature

Abstract

Hydrogen is considered a promising energy carrier for the future, especially for clean energy generation via fuel cell technologies. Formic acid is one of the prominent sources of clean and cheap hydrogen. In this work, Fe–Zn–Ir nanocatalysts show exceptional performance for selective hydrogen production via HCOOH decomposition, offering a promising alternative that could solve issues associated with hydrogen storage and distribution. Our results show that Fe atoms on the Fe–Zn–Ir surface are responsible for activating the HCOOH molecules; however, the identity of the surface metal atoms (Ir and Zn) dictate the selectivity of the reaction adjacent to the Fe atoms when there is no CO contamination. The high content of Fe atoms that reside at the Fe–Zn–Ir interface sites favored the dehydrogenation of HCOOH. The greater selectivity towards H2 was measured to be 97.4% at 30 min for the higher Fe content (50 wt%). These observations suggest that by controlling the arrangement of surface Fe, Zn, and Ir atoms, the reactivity and selectivity of HCOOH decomposition over Fe–Zn–Ir catalysts could be tailored, optimizing the surface composition. The findings in this study may prove informative for the rational design of Fe–Zn–Ir catalyst systems for reactions associated with hydrogen production, such as for fuel cell applications.