Supporting Information

Concave Cubes as Experimental Models of Catalytic Active Sites for the Oxygen-Assisted Coupling of Alcohols by Dilute (Ag)Au Alloys

Daniel D. Robertson, Melissa E. King and Michelle L. Personick*

Department of Chemistry, Wesleyan University, 52 Lawn Avenue,

Middletown, Connecticut 06459, United States

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Fig. S1Photograph of prepared concave cube catalyst on glass wool in a fritted quartz reactor tube.

Fig. S2Representative mass spectra for methanol coupling: (a) water; (b) methanol; (c) methyl formate; and (d) dimethyl carbonate. Characteristic peaks for dimethyl carbonate are m/z 59 and m/z 90.

Fig. S3RepresentativeTCD chromatogram for methanol coupling. Peaks from left to right are: (1) excess oxygen; (2) a small amount of carbon dioxide (< 1%); (3) water; (4) excess methanol; and (5) methyl formate.

Fig. S4Steady conversion of methanol to methyl formate by concave cubes over an extended period of time. Conditions: 10% methanol and 20% O2 in He (50 mL/min), 150 °C, 6.0 mg of catalyst.

Table S1Range of methanol conversion rates with different catalyst preparation methods.

Activation Method / Mass (mg) / Conversion / Rate of Conversion of Methanol (mmol s-1 g-1) / Catalyst Preparation
Reactant / 4.69 / 75% / 0.59 / low centrifugation,
heavy washing
Reactant / 5.78 / 32% / 0.20 / moderate centrifugation, light washing
Reactant / 1.99 / 25% / 0.46 / moderate centrifugation, moderate washing
Reactant / 2.51 / 25% / 0.36 / moderate centrifugation, moderate washing
Reactant / 1.28 / 50% / 1.44 / high centrifugation,
heavy washing
Reactant / 1.64 / 34% / 0.77 / high centrifugation,
heavy washing
Reactant / 6.05 / 68% / 0.42 / low centrifugation,
heavy washing*
Ozone Treatment / 5.02 / 49% / 0.36 / low centrifugation,
heavy washing

* This preparation method gives the most reproducible activity and is described in detail in the Experimental section. The highlighted data is reported in the main text.

Fig. S5Representative GC-MS data for ethanol coupling. (a) GC chromatogram showing peaks for (c) acetaldehyde; (d) ethanol; and (e) ethyl acetate. The ethyl acetate peak is highlighted in the inset. A representative mass spectrum for each peak is shown in c-e. (b) TCD chromatogram showing excess oxygen and small peaks for acetaldehyde and ethanol.

Fig. S6 Large area SEM image of as-prepared concave cubes.

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