Steering the methanol steam reforming reactivity of intermetallic Cu-In compounds by redox activation: stability formation of an intermetallic compound-oxide interface
To compare the inherent methanol steam reforming properties of intermetallic compounds and a corresponding intermetallic compound-oxide interface, we selected the Cu-In system as a model to correlate the stability limits, self-activation and redox activation properties with the catalytic performance...
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| Published in | Catalysis science & technology Vol. 11; no. 16; pp. 5518 - 5533 |
|---|---|
| Main Authors | , , , , , , , , , |
| Format | Journal Article |
| Published |
16.08.2021
|
| Online Access | Get full text |
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| Summary: | To compare the inherent methanol steam reforming properties of intermetallic compounds and a corresponding intermetallic compound-oxide interface, we selected the Cu-In system as a model to correlate the stability limits, self-activation and redox activation properties with the catalytic performance. Three distinct intermetallic Cu-In compounds - Cu
7
In
3
, Cu
2
In and Cu
11
In
9
- were studied both in an untreated and redox-activated state resulting from alternating oxidation-reduction cycles. The stability of all studied intermetallic compounds during methanol steam reforming (MSR) operation is essentially independent of the initial stoichiometry and all accordingly resist substantial structural changes. The inherent activity under batch MSR conditions is highest for Cu
2
In, corroborating the results of a Cu
2
In/In
2
O
3
sample accessed through reactive metal-support interaction. Under flow MSR operation, Cu
7
In
3
displays considerable deactivation, while Cu
2
In and Cu
11
In
9
feature stable performance at simultaneously high CO
2
selectivity. The missing significant self-activation is most evident in the
operando
thermogravimetric experiments, where no oxidation is detected for any of the intermetallic compounds.
In situ
X-ray diffraction allowed us to monitor the partial decomposition and redox activation of the Cu-In intermetallic compounds into Cu0.9In0.1/In
2
O
3
(from Cu
7
In
3
), Cu
7
In
3
/In
2
O
3
(from Cu
2
In) and Cu
7
In
3
/Cu0.9In0.1/In
2
O
3
(from Cu
11
In
9
) interfaces with superior MSR performance compared to the untreated samples. Although the catalytic profiles appear surprisingly similar, the latter interface with the highest indium content exhibits the least deactivation, which we explain by formation of stabilizing In
2
O
3
patches under MSR conditions.
To compare the properties of intermetallic compounds and intermetallic compound-oxide interfaces, Cu-In was used as a model to correlate stability limits, self-activation and redox activation with the inherent methanol steam reforming performance. |
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| Bibliography: | 10.1039/d1cy00913c Electronic supplementary information (ESI) available. See DOI |
| ISSN: | 2044-4753 2044-4761 |
| DOI: | 10.1039/d1cy00913c |