SCIENCEsciencemag.org 9JULY2021•VOL 373 ISSUE 6551 221
Fig. 4. Characterization of Pt 1 Sn 1 /SiO 2 catalysts.(A)DRIFTSspectraof
adsorbed CO on Pt 1 Sn 1 /SiO 2 .(B) Pt 4f photoemission spectra of reduced
Pt 1 Sn 1 /SiO 2 .(C) Sn 3d photoemission spectra of reduced Pt 1 Sn 1 /SiO 2.
(D) EXAFS magnitude of the Fourier transform (FT) of Pt 1 Sn 1 /SiO 2 measured
at room temperature in He after reduction in H 2 at 373 K. Coordination
numbers for Pt-Sn and Pt–Pt are 4.2 ± 0.4 and 3.9 ± 0.9, respectively, and
bond distances for Pt-Sn and Pt-Pt are 2.72 ± 0.01 and 2.75 ± 0.02,
respectively (table S3). R, radial distance. (E)PtLIII-edge XANES spectra of
Pt 1 Sn 1 /SiO 2 reduced at 600°C and of Pt foil. (Inset) Pt LIII-edge XANES
spectra of Pt 1 Sn 1 /SiO 2 collected at different temperatures while the catalyst
was reduced from 55° to 600°C. (F) Sn K-edge XANES spectra of Pt 1 Sn 1 /SiO 2 ,
SnO 2 , and Sn foil.RESEARCH | REPORTS