Supporting Information Study of methane oxidation over alumina supported Pd-Pt catalysts using in situ DRIFTS and XAS techniques Natalia M. Martin,∗,† Johan Nilsson,† Magnus Skoglundh,† Emma Adams,† Xueting Wang,† Gudmund Smedler,‡ Agnes Raj,¶ David Thompsett,¶ Giovanni Agostini,§ Stefan Carlson,k Katarina Norén,k and Per-Anders Carlsson† Competence Centre for Catalysis, Chalmers University of Technology, Gothenburgh, 412 96, Sweden, Johnson Matthey AB, Västra Frölunda, 421 31, Sweden, Johnson Matthey, Reading, RG 9NH, United Kingdom , European Synchrotron Radiation Facility, Grenoble, 38043, France, and MAX-IV Laboratory, Lund University, Lund, 221 00, Sweden E-mail: [email protected] Figure S1 shows the integrated IR peak areas for the CO adsorbed on linearly and bridge configurations on the metal during the transient methane oxidation reaction performed by periodic variation of the gas composition between net-oxidising (1.5% O2 + 0.1% CH4 ) and net-reducing (0.1% CH4 ) conditions at 360 ◦ C. ∗ To whom correspondence should be addressed Chalmers University ‡ Johnson Matthey, Sweden ¶ Johnson Matthey, UK § ESRF k MAX IV Laboratory † S1 Pd-Pt F500 IR peak area Pd-Pt L800 bridging CO bridging CO 400 2 300 1 CO linear CO 200 CO linear CO 0 CO linear CO 100 0 1600 1800 2000 Time (s) 2200 2400 1600 1800 2000 Time (s) 2200 2400 1600 1800 2000 Time (s) 2200 2400 Figure S1: Transient oxidation of 0.1% CH4 over the Pd-Pt/Al2 O3 F500 (left panels), PdPt/Al2 O3 F800 (middle panels) and Pd-Pt/Al2 O3 L800 (right panels) powder catalysts during periodic variation of the feed gas composition between lean (0.1% CH4 and 1.5% O2 , pale red marked areas) and rich (0.1% CH4 ) periods for 180 s at 360 ◦ C. The figure shows the integrated peak areas of linearly (blue, IR bands between 2000-2100 cm−1 ) and bridge (red, IR bands between 1730-2000 cm−1 ) adsorbed CO on the metal (Pd/Pt) versus time recorded during the lean-rich cycling experiment (cycles no. 5 to 7), together with the CO outlet concentration (black) measured by a mass spectrometer. Figure S2 shows the selected IR spectra during the isothermal CO exposure measurement (0.05% CO) after the methane and oxygen have been removed from the feed at the end of the methane oxidation experiments performed at 360 ◦ C. S2 CO concentration (ppm) bridging CO 3 Pd-Pt F800 Pd-Pt F500 Pd-Pt F800 1922 cm-1 1922 cm-1 1922 cm-1 2051 cm-1 Absorbance (arb.u.) Pd-Pt L800 605 s 605 s 562 s 562 s 519 s 519 s 476 s 476 s 433 s 433 s 2051 cm -1 605 s 562 s 519 s 476 s 433 s 390 s 390 s 390 s 2051 cm-1 347 s 347 s 347 s 304 s 304 s 304 s 261 s 261 s 261 s 218 s 218 s 218 s 175 s 175 s 175 s 2400 132 s 132 s 132 s 89 s 89 s 46s 46s 0s 0s 2200 2000 1800 Wavenumber (cm-1) 89 s 46s 1600 2400 0s 2200 2000 1800 Wavenumber (cm-1) 1600 2400 2200 2000 1800 Wavenumber (cm-1) 1600 Figure S2: Evolution of IR absorption bands in the wavenumber region 1500-2500 cm−1 for the Pd-Pt/Al2 O3 F500 (left panel), Pd-Pt/Al2 O3 F800 (middle panel) and Pd-Pt/Al2 O3 L800 (right panel) catalysts exposed to 0.05% CO for 10 min after methane oxidation reaction at 360 ◦ C. The insert numbers indicate the time (in seconds) where the spectra were recorded. S3
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