Temperature-programmed reduction (TPR) profiles were recorded using
a Micrometrics AutoChem II chemisorption analyzer.
TPR was used to determine the number and type of redox species
present in the catalysts.
Before
TPR analysis, 48mg of the sample was heated in helium at 365 K for 15
min and then cooled to room temperature. The calcined samples were
heated ( 10 oC
min-1)
under a 12 v% H2-Ar
mixture (feed flow rate: 50 mL min-1)
and hydrogen consumption was measured by a thermal conductivity
detector (TCD).
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