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Aqueous-Phase Reforming and BioForming Process
considered liquid byproducts. At 250°C, hydrogen selectivity was always higher than
80% and the formation of CO was very low (<3%). The addition of Cu decreased the
formation of methane.
Wen et al. [39] examined the activities and stabilities of Pt, Ni, Co, and Cu
catalysts and supports for H 2 production by APR of glycerol. The experimental data
were taken in a continuous flow fixed-bed reactor. It was found that the activity of
the metal catalysts increased in the order of Co, Ni, Cu, and Pt. Additionally, Pt
was highly stable, whereas Ni and Co showed a significant deactivation with time
on stream. It was also found that the activity of Pt catalysts on various supports
follows the order: SAPO-11 < active carbon (AC) < HUSY < SiO 2 < MgO < Al 2 O 3 .
Moreover, the basic support resulted in high activity and higher hydrogen molar
concentration, whereas acidic support and neutral Al 2 O 3 support tended to increase
alkanes formation. It was shown by x-ray diffraction (xRD) that Pt was caused to
sinter on all of the supported Pt catalysts during the reaction. In addition, a trace
amount of carbon deposition was found on all of the supported Pt catalysts. However,
no remarkable deactivation was observed over Pt/Al 2 O 3 , Pt/SiO 2 , Pt/AC, and Pt/
HUSY catalysts. Two zeolite-supported catalysts showed low activities as well as
the collapse of the support. In addition, little influence of the collapse of the support
on the stability of Pt/HUSY was observed. Pt/SAPO-11 catalyst exhibited very high
deactivation.
Cho et al. [57] examined APR of glycerol over Ni-based catalysts for hydrogen
production. The reforming was carried out at 225°C, 23 bar, and liquid hourly space
velocity (LHSV) = 4 h −1 . The Ni-based catalyst was prepared by an incipient wetness
impregnation method. It was found that Ni (20 wt%)−Co (3 wt%)/γ-Al 2 O 3 catalyst
showed higher glycerol conversion and hydrogen selectivity than Ni (20 wt%)/γ-Al 2 O 3
catalyst. There were no major changes in Ni particles after the reaction over Ni−Co/
γ-Al 2 O 3 catalyst. The results suggest that the Ni−Co/γ-Al 2 O 3 catalyst can be applied
to the hydrogen production system using APR of glycerol.
6.5.4.2 aPr of sugar and Glucose (Primary Feedstock
with low Vapor Pressure)
Tanksale et al. [42] examined the hydrogen production by APR of sugar solutions
using metal-supported catalysts. The aim of this study was to examine the influence
of several reaction parameters on hydrogen production using liquid-phase reforming
of sugar solution over Pt, Pd, and Ni supported on nanostructured supports. It was
found that the desired catalytic pathway for H 2 production involves cleavage of C–C,
C–H, and O–H bonds that adsorb on the catalyst surface. Thus, a good catalyst for
the production of H 2 by liquid-phase reforming must facilitate the C–C bond cleavage and promote the removal of adsorbed CO species by the water–gas shift reaction,
but the catalyst must not facilitate the C–O bond cleavage and hydrogenation of CO
or CO 2 . Apart from studying various catalysts, a commercial Pt/γ-alumina catalyst
was also examined at three different temperatures: 458, 473, and 493  K. On the
surface of some of the spent catalysts, the amorphous and organized form of coke
was found. APR of sugar solution was also studied by Blommel and Cortright [15],
Cortright [8,66], and Held [67].