Topics in Catalysis – Supplementary Information
̅𝟎𝟎)
CH3CH2OH, CD3CD2OD, and CF3CH2OH decomposition on ZnO(𝟏𝟏
Aaron Reinicker1, James B. Miller1, Wooseok Kim2, Kijung Yong2, Andrew J. Gellman1
1
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
2
Department of Chemical Engineering, Pohang University of Science and Technology,
Gyeongsangbuk-do, South Korea
* Corresponding author: gellman@cmu.edu, 412-268-3848
1
Table S1 – Matrix of mass spectral sensitivities, 𝛼𝑖𝑗 =
𝑑𝐼𝑖𝑗
𝑑𝑃
, for ionization fragments of
CH3CH2OH and its decomposition/desorption products CH3CH2OH, CH3CH=O, H2, H2O, and
CH2CH2. Each pure compound, i, was leaked into the UHV chamber at 4 different pressures and
the signals for ionization fragments, j, at m/z = 2, 18, 28, 29, and 31 were recorded to calculate
𝛼𝑖𝑗 . This matrix was used to convert the CH3CH2OH/ZnO(11̅00) TPRS signals at each m/z to
pressures of each product.
̅𝟎𝟎) TPRS Products
CH3CH2OH/ZnO(𝟏𝟏
m/z
H2
H2 O
CH2=CH2
CH3CH=O
CH3CH2OH
2
420
5.0
5.9
17
46
18
9.2
180
4.6
25
110
28
2.3
6.6
350
67
93
29
1.1
0.0
5.98
200
120
31
0.0
0.0
0.0
0.0
110
2
Table S2 – Matrix of mass spectral sensitivities, 𝛼𝑖𝑗 =
𝑑𝐼𝑖𝑗
𝑑𝑃
, for ionization fragments of
CD3CD2OD and its decomposition products CD3CD2OD, CD3CD=O, D2, D2O, and CD2CD2.
Each pure compound, i, was leaked into the UHV chamber at 4 different pressures and the
signals for ionization fragments, j, at m/z = 4, 20, 32, 30, and 34 were recorded to calculate 𝛼𝑖𝑗 .
This matrix was used to convert the CD3CD2OD /ZnO(11̅00) TPRS signals at each m/q to
pressures of each product.
̅𝟎𝟎) TPRS Products
CD3CD2OD/ZnO(𝟏𝟏
m/z
D2
D2O
CD2=CD2
CD3CD=O
CD3CD2OD
4
250
0.4
1.7
4.5
11
20
0.7
40
0.9
16
20
32
2.2
0.6
230
3.6
48
30
1.1
0.7
140
240
170
34
0.0
0.0
0.0
0.0
55
3
Figure S1. LEED pattern of the clean ZnO(11̅00) surface at 100 K (E = 150 eV).
4
2.5
CH3CH2OH
370 K
2.0
Pressure (x10-10 Torr)
Pressure (x10-10 Torr)
5
4
3
438 K
2
fitted
spectrum
1
0
300
350
400
450
500
550
600
650
435 K
CH3CH=O
495 K
1.5
1.0
0.5
fitted
spectrum
0.0
-0.5
300 350 400 450 500 550 600 650 700
700
Temperature (K)
Temperature (K)
Figure S2. Peak fitted TPRS spectra (black) of CH3CH2OH and CH3CH=O desorption from
̅𝟎𝟎). Two Lorentzian functions were used to fit
a 0.4 L exposure of CH3CH2OH to ZnO(𝟏𝟏
each spectrum. The blue curve shows the fitted TPR spectrum determined from the sum of
both peaks.
5
491 K
1.5
1.0
3.0
CD3CD=O
432 K
fitted
spectra
0.5
0.0
Pressure (x10-10 Torr)
Pressure (x10-10 Torr)
2.0
490 K
2.5
CD2=CD2
2.0
fitted
spectra
1.5
1.0
0.5
0.0
300 350 400 450 500 550 600 650 700
300 350 400 450 500 550 600 650 700
Temperature (K)
Temperature (K)
Figure S3. Peak fitted TPRS spectra (black) for CD3CD=O and CD2=CD2 desorption after a
0.9 L exposure of CD3CD2OD to ZnO(11̅00). Two Lorentzian functions were used to fit the
spectra of CD3CD=O while one Lorentzian function was used to fit the spectra of CD2=CD2.
The blue curve shows the fitted TPR spectrum determined from the peak(s).
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m/z
Signal (arb. units)
18
29
31
45
300 350 400 450 500 550 600 650 700
Temperature (K)
̅𝟎𝟎).
Figure S4. TPR spectra obtained following a 0.1 L exposure of CF3CH2OH to ZnO(𝟏𝟏
CF3CH2OH was exposed at 300 K by background dosing. The signal measured for H2O is
m/z =18, CF3CH=O (29), CF2=CH2 (45) CF3CH2OH (31). For a 0.1 L exposure, the signal at
m/z = 29 is greater than that at m/z = 31, while the opposite is true for the 4 L exposure shown
in Figure 6. This shows that the sites for CF3CH=O formation saturate before sites for
reversible CF3CH2OH adsorption.
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Signal (arb. units)
3 L D 2O
3 L H2O
background
300
350
400
450
500
550
600
650
700
Temperature (K)
Figure S5. TPR spectrum of H2O (m/z = 18) following a 3 L exposure of CH3CH2OH to
ZnO(11̅00) compared to a TPR spectrum of D2O (m/z = 20) from a 3 L exposure of
CD3CD2OD and a TPR spectrum (m/z = 18) after a 20 min exposure of the clean ZnO(11̅00)
surface to the chamber background. There is no evidence of H2O adsorption during exposure
of the clean surface to the background vacuum.
8