Green Chemistry
Communication
the Analytical Science Division, Indian Institute of Petroleum
for analytical services and the CSIR, New Delhi for the finan-
cial support in the form of 12 FYP Project (CSC-0125 and
CSC-0117). The XAFS measurements were performed at
KEK-IMSS-PF, Tsukuba, Japan with the approval of the Photon
Factory Advisory Committee (project 2013 G 210).
Notes and references
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Scheme 2 Probable mechanistic pathway.
pound which will further reduce to the hydroxyamino com-
pound. Finally, hydroxyl amine will reduce to aniline. To
obtain an insight into the reaction pathway involved in the
reduction process, the reaction intermediates involved in both
the routes were separately subjected to a reduction process
using the 0.9% Pt-CeO2 catalyst; when p-nitrosophenol was
subjected to a reduction, it gave p-aminophenol within 5 h
and when p-(hydroxyamino) phenol was subjected to
a reduction it produced aminophenol within 3 h (Table 2,
entries 11 and 12).
The reusability of the catalyst 0.9% Pt-CeO2 was studied
without any regeneration. The catalyst was repeatedly washed
with ethanol and acetone and dried overnight at 100° C and
used as such. It was observed that the catalyst 0.9% Pt-CeO2
does not change its activity (conversion and selectivity) after
five successive runs (ESI Fig. S4†). The amount of Pt present in
the catalyst after 5 runs is almost the same as the fresh catalyst
(estimated by ICP-AES), confirming the true heterogeneity of
the catalyst.
In summary, Pt-nanoparticles with size between 2 and
5 nm supported on the nanocrystalline CeO2 were prepared by
the hydrothermal method in the presence of the surfactant.
0.9 (wt%) Pt supported on the CeO2 support shows a p-nitro-
phenol conversion of 100% with 99% p-aminophenol selecti-
vity after 6 h at 25 °C in the presence of molecular hydrogen.
This catalyst shows very good activity towards chemoselective
reduction for different nitro-compounds. The catalyst can be
reused several times without any considerable decrease in
its physiochemical properties and reactivity. This catalyst
can replace the existing hydrogenation process where hazar-
dous hydrogenating agents like LiAlH4, NaBH4 can be avoided
and can make this process environmentally friendly. This cata-
lyst can be used for the removal of harmful pollutants from
waste water at 25 °C.
Acknowledgements
The Director, CSIR-IIP, is acknowledged for his help and
support. R. S. thanks UGC for a fellowship. The authors thank
This journal is © The Royal Society of Chemistry 2014
Green Chem.