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