• Palladium is important catalyst in reactions involving electro-oxidation and reduction of oxygen.
• There are various palladium nanostructures preparation method, wherein the SPE reactors are used for the hydrogenation of organic compounds.
• However, untreated carbons are often hydrophobic in nature that allows poor adsorption of catalyst precursors and catalysts.
• The deposition of metals on the electrochemically activated carbon black substrates favored a good deposition and well dispersion, but with spherical  morphology.

Hence there is a need to develop an improved method to  overcome above-mentioned issues.

A method of preparing palladium dendrites without using  a template, surfactant and additive comprising:

• Coating carbon on a graphite substrate by  dispersing carbon powder in a mixture of  an ionomer and a solvent followed by  blending.
• Activating the carbon surface  electrochemically by potential cycling in  an acidic electrolyte.
• Electrodepositing palladium on the  electrochemically activated carbon coated  graphite substrate by potential cycling for  10 to 25 cycles using palladium chloride as  a precursor at a conc of 1.5 mM to 3 mM.

Wherein, the graphite substrate is graphite electrode,  and the carbon is Vulcan XC-72R, functionalized Vulcan  XC-72R, carbon nanotubes (CNT), functionalized CNT,  and made from wood apple fruit or graphene. Refer to  FIG 1 & 2.

• The morphology of the palladium particles is tailored from spherical to dendritic structure:

1. by increasing electrochemical activation cycles  from 25 to 100 cycles
2. by increasing the metal deposition cycles from 10 to 25 cycles
3. by increasing loading of the carbon substrate  from 100 µg cm-2 to 400 µg cm-2
4. by increasing the precursor concentrations from 1.5 mM to 3 mM.

Wherein controlling the activation cycles, deposition cycles, carbon loading & precursor concentrations increases dendrites growth and  initiates growth on already grown palladium  dendrites. The method has following Properties:

1. The ionomer is Nafion & the solvent is isopropanol, the acidic medium is perchloric acid with 0.01 M strength. The blending is  performed ultrasonically followed by air drying.
2. The acidic electrolyte is sulfuric acid with a strength of about 0.5 M. The electrochemical activation increases hydrophilicity and generates  surface defects on the carbon substrate.