Structural understanding of IrFe catalyst for renewable hydrogen production from ethanol steam reforming

Ethanol steam reforming (ESR) is an attractive way to produce renewable H2 and has been intensely studied. An iron promoted Ir catalyst IrFe/Al2O3 is reported for the first time to show better performance than Ir/Al2O3 in ESR and the structural change in the IrFe/Al2O3 catalyst under realistic ESR conditions is investigated. IrFe alloy is observed after reduction in H2. However, the IrFe alloy is disrupted during ESR because of an adsorptioninduced structural change. Ir appears in metallic-like state while Fe exists as partially reduced FexOy under the reaction condition. The active center is therefore IrFexOy instead of IrFe alloy. The discovery of the transformation of IrFe alloy to IrFexOy during ESR deepens the understanding of the dynamic behaviour of IrFe catalyst and provides a correlation between the catalyst structure and catalytic performance.