Technology Category/Market
Chemical Engineering: Process design, Reaction Industry: Fuel cell, Reactor Design, Chemical mfg. Â Applications: Organic synthesis, hydrogen storage
Market: The global Palladium Catalyst market size was  valued at USD 547.99 M in 2022, expected with CAGR of  4.79%, reaching USD 725.68 million by 2028.
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Problem Statement
- Palladium is a catalyst used in variety of reactions involving electro-oxidation and reduction.
- Solid polymer electrolyte (SPE) reactors are made of palladium catalysts and allow facile transport of ionic species to the catalyst surface through the membrane  under an applied potential.
- However, the control over morphology of palladium nanostructures on carbon or CNTs based substrates has been difficult, especially with the conventional  method of the chemical reduction.
Hence, there is a demand of a new method to address  the above mentioned issues.
Technology
A method of preparing palladium dendrites
a) Coating carbon nano-tubes (CNTs) on a graphite substrate
b) Activating the substrate electrochemically
c) Electrodepositing palladium on the activated substrate
wherein steps a) to c) are carried out without  using a template, surfactant and/or additive.
- The morphology of the palladium particles from spherical to dendritic structure is tailored by controlling the deposition potential on  electrochemically activated CNTs substrate.
- The dendritic nanostructures is grown by increasing the precursor concentration at an appropriate deposition potential.
- The preparation of palladium dendrites is done at room temperature and atmospheric pressure.
- The CNT is coated as a thin layer on a graphite substrate (graphite electrode) by dispersing CNTs in a mixture of an ionomer (Nafion®) and solvent  (isopropanol), followed by blending ultrasonically.
- CNT loading on the graphite substrate is about 100 μg cm-2 and coated graphite is air dried.
- The CNT coated graphite substrate is activated electrochemically by potential cycling (100 cycles) in acidic electrolyte (sulfuric acid with  0.5M strength) that helps to improve hydrophilicity  & generates CNT surface defects.
- Platinum wire and Ag/AgCl (3M NaCl) is used as counter & reference electrodes, respectively.
- The potential range is -0.2 to 1.1 V vs. Ag/AgCl and scan rate is 100 mV s-1.
- Palladium is deposited by constant potential technique and the deposition potential and precursor concentration are modified to increase  the dendritic morphology.
Fig. 1 provides scanning electron micrographs of  electrodeposited Pd on electrochemically activated  CNT coated substrate at
a) 2 V, b) 0.3 V, c) 0.4 V and d) 0.5 V.
Fig. 2 provides scanning electron micrographs of  electrodeposited Pd on electrochemically activated  CNT coated substrate at 0.2 V with varying  precursor concentrations:
(a) 1 mM, (b) 1.5 mM and (c) 2 mM.
Wherein, CNTs were electrochemical activation in nitrogen saturated 0.5 M H2SO4 prior to deposition.
Key Features/Value Proposition
Technical Perspective
- The palladium dendrites have increased surface area and highly efficient catalytic activity, that is highly preferable for their use.
Industrial Perspective
- Used in the field  of fuel cells, organic synthesis, hydrogen storage and sensing.
- Used in the SPE reactors to enhance the hydrogenation reaction rates of triglycerides.
User Perspective
- Environment friendly & are widely preferred.
Questions about this Technology?
Contact for Licensing
Research Lab
Prof: Raghuram Chetty
Department of Chemical Engineering
Intellectual Property
- IDF Ref: 889
- IN Patent No. 306280 (Granted)
- PCT Application No. PCT/IN2013/000522
Technology Readiness Level
TRL- 3/4
Proof of concept ready Stage
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