Stabilization of Iron-Based Catalysts against Oxidation: An In Situ Ambient-Pressure X-ray Photoelectron Spectroscopy (AP-XPS) Study

Stabilization of base metals at low oxidation state is of vital importance in their application as heterogeneous catalysts, especially in the presence of water. In this work, addition of a small amount of Pd on Fe surface was found to provide a remarkable enhancement of its stability in hydrodeoxygenation (HDO) of m-cresol. The deactivation of Fe catalyst and the effect of Pd on the stability of Fe were uncovered with an in situ ambient-pressure X-ray photoelectron spectroscopy (XPS). The deactivation is attributed to oxidation of the catalytic active metallic Fe during reaction, while Pd addition limits the steady-state coverage of oxidized Fe on the surface.