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nanoparticles formed by leaf powder and leaf extract at dif erent pH values
of 4-8 and in the temperature range of 300-373 K. Using leaf powder was
found to be advantageous over leaf extract due to the elimination of the
seasonal ef ects and also because its concentration can be optimized; it was
also concluded that Au nanoparticles were more stable at pH 6, while Ag
nanoparticles were found to be stable at pH 8.
10.2.4 Palladium Nanoparticles
Currently, the applications of palladium nanoparticles in many i elds have
increased the interest of researchers in the development of green chemis-
try, ei cient methods for its synthesis. Fabrication of palladium nanopar-
ticles with mean size of nanoparticles, ranging from 3.2 to 6.0 nm, using
broth of Cinnamomum camphora leaf without adding surfactant, capping
agent, and/or template have been reported by Yang and coworkers [102].
Kanchana et al. [103] used leaf extract of Solanum trilobatum to produce
palladium nanoparticles of dif erent sizes. Sathishkumar and coworkers
[104] also reported for the i rst time the production of nanocrystalline pal-
ladium nanoparticles by using Curcuma longa tuber extract as biomaterial.
h ey proposed that the polyphenolic compounds present in the extract
are responsible for the reduction of palladium nanoparticles. Likewise,
in their research experiment Bankar and colleagues [46] synthesized pal-
ladium nanoparticles by using boiled, crushed, acetone precipitated, and
air-dried  peel extract of banana as a reducing material. Song et al. [47]
investigated the reducing properties of the leaf extract of Diopyros kaki
for the extracellular synthesis of platinum nanoparticles from an aqueous
H 2 PtCl 6 6H 2 O solution. h ey reported that a leaf broth concentration of
>10% could result in the 90% conversion of platinum ions to nanoparticles
with average particle size ranging from 2 to12 nm.
Sheny et al. [101] have studied the formation of spherical palladium
nanoparticles by using the dried leaf powder of  Anacardium occidentale.
X-ray dif raction (XRD) results proved that the palladium nanoparticles
had crystalline forms with fcc structure. h e TEM analysis showed that
the formed nanoparticles were about 2-5 nm in size. h is synthesis pro-
posed that the polyols  found in the leaf extracts are responsible for the
reduction of Pd(II) ions. Another biosynthesis of Pd nanoparticles
(3-5  nm) in the presence of palladium chloride using antioxidants such
as geniposide, chlorogenic acid, crocins and crocetin of Gardenia jasmin-
oides Ellis as reducing and stabilizing agents has been reported by Jia et al.
[105]. Nadagouda and Varma [106] have prepared silver and palladium
nanoparticles by a simple green approach using cof ee and tea extract at
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