Alleviating inhibitory effect of H2 on low-temperature water-gas shift reaction activity of Pt/CeO2 catalyst by forming CeO2 nano-patches on Pt nano-particles

Abstract

Pt/CeO2 has gained much attention for their high activity in low-temperature (LT) water-gas shift (WGS) reaction. However, the inclusion of H2 in the feed as in the practical reaction condition significantly degrades the LT-WGS activity of the Pt/CeO2 catalysts. In this contribution, the activity of Pt/CeO2 catalyst under the feed gas containing excess H2 (20 vol% of H2) was enhanced more than three times by forming CeO2 nano-patches on Pt nano-particles. Both in-situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculation results indicate that dissociated H2 on the Pt nano-particle inhibits the activity of the Pt/CeO2 catalysts by occupying the active sites (Pt nano-particle-CeO2 interface). On the other hand, thin CeO2 nano-patches on Pt nano-particle suppressed the H2 dissociation. As a result, the WGS reactivity of the active Pt nano-particle-CeO2 interface was less affected by H2, granting the catalysts the high activity under the practical reaction conditions.