Before the batch reactions, RuM3/CeO2 and
M3/CeO2 (M = Fe, Co, Ni) catalysts were reduced
in a tube furnace by a 50 vol % H2/Ar flow at elevated
temperatures for 60 min with a ramp rate of 10 °C/min, with
the reduction temperature being determined via H2-TPR profiles,
similar to those described for CO chemisorption experiments. There
was no prereduction process for Ru/CeO2 since Ru could
be fully reduced below the reaction temperature (250 °C). Afterward,
the reduced sample was cooled down in Ar to room temperature and passivated
by 1 vol % O2/Ar for 15 min before being transferred to
the batch reactor, a 4598 Parr micro stirred reactor. For each measurement,
10–200 mg of the reduced catalyst was loaded into a small beaker
and mixed with 1 g of reactant (LDPE with Mw ∼ 4000 Da or n-hexadecane) before being
added to a 100 mL stainless steel autoclave. The reactor was tightly
sealed and purged with H2 (18 bar) six times prior to being
filled to the target H2 pressure (5 or 18 bar). The reactor
was heated to reaction temperature (200 or 250 °C) in 40 min,
maintained at the reaction temperature for a specific time (30–600
min) under agitation, and then cooled down to room temperature before
collecting gases, liquids, and solid residues for product analysis.
M3/CeO2 (M = Fe, Co, Ni) catalysts were reduced
in a tube furnace by a 50 vol % H2/Ar flow at elevated
temperatures for 60 min with a ramp rate of 10 °C/min, with
the reduction temperature being determined via H2-TPR profiles,
similar to those described for CO chemisorption experiments. There
was no prereduction process for Ru/CeO2 since Ru could
be fully reduced below the reaction temperature (250 °C). Afterward,
the reduced sample was cooled down in Ar to room temperature and passivated
by 1 vol % O2/Ar for 15 min before being transferred to
the batch reactor, a 4598 Parr micro stirred reactor. For each measurement,
10–200 mg of the reduced catalyst was loaded into a small beaker
and mixed with 1 g of reactant (LDPE with Mw ∼ 4000 Da or n-hexadecane) before being
added to a 100 mL stainless steel autoclave. The reactor was tightly
sealed and purged with H2 (18 bar) six times prior to being
filled to the target H2 pressure (5 or 18 bar). The reactor
was heated to reaction temperature (200 or 250 °C) in 40 min,
maintained at the reaction temperature for a specific time (30–600
min) under agitation, and then cooled down to room temperature before
collecting gases, liquids, and solid residues for product analysis.
