Hydrogen Adsorption/Desorption Isotherms on Supported Platinum Nanoparticles Determined by <i>in‐situ</i> XAS and ΔXANES Analysis
Masami Fujita, Akira Yamamoto, Naoki Tsuchiya, Hisao Yoshida
Abstract
Abstract Hydrogen atoms on supported metal nanoparticles (NPs) play a significant role in heterogeneous catalysis. Despite the extensive previous research, however, the adsorption of hydrogen onto practical supported NP catalysts is still unclear especially in the atmospheric pressure conditions. In this study, adsorption/desorption isotherms of hydrogen on Pt NPs supported on alumina (Al 2 O 3 ) were obtained in gas‐flow conditions using the analysis of the difference spectra of Pt L III ‐edge X‐ray absorption spectroscopy (XAS) at 303 K. From the analysis of extended X‐ray absorption fine structure (EXAFS), a positive linear relationship was observed between the hydrogen coverage and Pt−Pt bond distance. Additionally, the re‐adsorption experiment of hydrogen after the first adsorption/desorption cycle and the transient change of dispersive XAS spectra in the hydrogen adsorption suggests that the hydrogen adsorption induces the surface reconstruction of Pt NPs on Al 2 O 3 at around room temperature and atmospheric pressure.