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Composition-directed FeXMo2−XP bimetallic catalysts for hydrodeoxygenation reactionsElectronic supplementary information (ESI) available: Reaction mechanisms (HDO2 and HDO3), lattice parameters (Table S1), surface energies (Table S2), molar ratios of Fe to Mo (Table S3), in situ DRIFT bands of pyridine (Table S4), bond lengths (Table S5), effect of the change in the K-points grid on activation energy barrier (Table S6), adsorption energies of n-alkanes (Table S7), activation energies required fo
The development of task-specific bimetallic phosphide catalysts can be accomplished by exploiting the electronic and bi-functional effects of multiple metal combinations, thus providing materials with tunable catalytic properties. Here, we present the modulation of metal compositions ( i.e. , Fe and...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Online Access: | Get full text |
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| Summary: | The development of task-specific bimetallic phosphide catalysts can be accomplished by exploiting the electronic and bi-functional effects of multiple metal combinations, thus providing materials with tunable catalytic properties. Here, we present the modulation of metal compositions (
i.e.
, Fe and Mo) in the synthesis of Fe
X
Mo
2−
X
P (0.88 ≤
X
≤ 1.55), leading to a series of
iso
-structural, orthorhombic Fe
X
Mo
2−
X
P catalysts
via
reduction at 750 °C. Hydrodeoxygenation of phenol was selected as a probe reaction to showcase the effect of metal composition on the catalytic performance. In particular, catalysts with Fe compositions between 0.99 and 1.14 (
i.e.
, Fe
0.99
Mo
1.01
P and Fe
1.14
Mo
0.86
P) exhibited high selectivities to C-O bond cleavage of phenol with H
2
to form benzene. The catalysts with the highest selectivities to C-O scission also exhibited the highest acidity as determined from NH
3
temperature programmed desorption experiments. Density functional theory (DFT) calculations indicate the high Lewis acidity for the ∼1 : 1 Fe : Mo compositions resulted from a greater charge separation between metallic species and P species. These compositions led to greater selectivities to benzene due to desired coordination environment of the phenol on catalytic surface, as evidenced by both DFT calculations and a time on stream study using a benzonitrile poison. Enhanced TOFs were also observed with catalysts exhibiting greater Lewis acid character, which reduce the activation energy required to cleave the C-O bond of phenol, as evidenced by DFT calculations. This structure-property study highlights the effects of metal composition in bimetallic phosphides to enhance the activity and selectivity for C-O bond cleavage reactions.
Compositional variation in Fe
X
Mo
2−
X
P catalysts alters their Lewis acidities, leading to modulated catalytic performance in the hydrodeoxygenation of phenol. |
|---|---|
| ISSN: | 2044-4753 2044-4761 |
| DOI: | 10.1039/c7cy00324b |