How Do Structurally Distinct Au/α‐Fe₂O₃ Interfaces Determine Surface OH/H₂O reactivity, Intermediate Evolution, and Product Formation in Low‐temperature Water‐gas Shift Reaction?

Abstract

Three structurally distinct interfaces, i. e. Au/α‐Fe2O3‐THB‐Air, Au/α‐Fe2O3‐HS‐Air, and Au/α‐Fe2O3‐QC‐Air, with the major substrate facet being {113}, {001}, and {012} respectively, were controllably prepared. The low temperature water gas shift (WGS) reaction (100–260 °C) was applied to these unique systems to reveal how these structurally distinct interfaces can impact on the reaction behavior. With the detailed performance evaluation plus the characterizations of CO‐TPSR, XPS, and in situ‐FTIR in particular, the correlations between the evolution of different intermediates and the distinct catalytic behaviors have been established. The substrate facet structure and the Au entity largely determine the form and reactivity of surface OH/H2O species which in turn determine the formation of different intermediates and eventually the product formation. The Au/α‐Fe2O3‐THB‐Air is enriched with oxygen vacant sites, favorable for dissociative adsorption of H2O, carboxyl intermediate formation and H2 production. The Au/α‐Fe2O3‐HS‐Air is enriched with surface lattice oxygen, favorable for molecular adsorption of H2O, formate intermediate formation, and CO2 production. The Au/α‐Fe2O3‐QC‐Air interface is enriched with surface Fe sites, favorable for dissociative adsorption of H2O and evolution of stable carboxyl intermediate as well as isolated OH species at low reaction temperatures. The findings are informative to control the interfacial structure for the WGS and other reactions.

A Pt/SnO2/rGO interface more capable of converting ethanol to CO2 in ethanol electro-oxidation: a detailed experimental/DFT study

“…Our previous studies revealed that when the noble metals were deposited on the same kind of oxide with different facets, the resulting interfacial systems behaved very differently in a few catalytic reactions such as CO oxidation, water gas shi, hydrocarbon oxidation/ combustion, etc. [50][51][52][53][54][55] Here, not only the structural conguration but also the electron properties of the metal entity can be affected by the specic surface structure of the exposed SnO 2 substrate. In addition, the hydroxylation varies over the different facets of an oxide (specically SnO 2 in the current study), and the resulting OH species will be naturally distinct in reactivity.…”

Atomic Layer Deposition of Pt Fine Clusters over the Structurally Defined SnO2 Facets for Efficient Formic Acid Decomposition and H2 Evolution

“…In this way, metal particles with controllable particle sizes can be precisely deposited onto the structurally clear oxide support to establish unique metal–oxide interfaces applied for certain catalytic processes and to achieve a structure–performance correlation in depth. This is the major tactic of the present study, and such tactics have been successfully applied for a variety of catalyst systems and reactions in our lab. − …”