Electrocatalysis

ElectroCat

- in close collaboration with the group of Electron Microscopy and Catalysts from Department for Materials Chemistry (D10)

Dr. Nejc Hodnik
nejc.hodnik(at)ki.si

@Electrocatalyst

CV

Researchgate

Google Scholar
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Our motivation:

"Global energy crisis and subsequent climate changes (raising CO₂ levels in the athmospehere) are forcing world leaders to reconsider the fossil fuels as an energy source. The obvious long-term solution is to choose something that does not cause any harm to the environment and is available widely free of cost. All renewable energy sources like solar, wind, geothermal, hydropower and ocean energy are considered sustainable as they are stable and available in plenty. The current grand challenge is to store this intermittent energy to meet the demand. In the next years, we will witness the transition of a modern digital society to the hydrogen and circular economy where energy conversion (electricity to molecules and back) and critical raw materials recycling will play an essential role."

Appearance in the media: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

Our primary goal is to provide state of the art and fun working environment as a basis for successful pursuit of scientific challenges in the field of Energy Conversion & Corrosion where we are involved in electrochemical characterisation of materials for electrocatalytic applications in low temperature (PEM) Fuel Cell and Electrolyzers with techniques like Thin Film Rotating Disc Electrode (RDE), XRD, Identical Location Electron Microscopy (IL-EM), in-situ Microscopy, Electrochemical Flow Cell coupled to ICP-MS, ...

We are also looking for new ideas and ways to optimize electrochemical techniques, reactors, catalysts, synthesis procedures, ... Our ambition is to increase the performance of PEM fuel cells and electrolyzers (boost their activity and stability). We are also involved in developing new processes for platinum group metals recycling.

We are always looking for new collaborations either from industry or academic institutions. We also welcome young scientist that would like to experience working in a dynamic and relaxed scientific environment. We offer many interesting diploma topics.

Supported by:

Basic postdoctoral research project Z2-8161

(ARRS project)

Electrochemical recycling of noble metals

Department Team:

Léonard Jean Moriau, dr. Andraž Pavlišič, dr. Primož Jovanovič,

Visiting researchers:

- Bart Vanrenterghem (Researchgate), University of Antwerp, Belgium ("The reduction of benzylbromide at Ag-Pb nanoparticles prepared by galvanic replacement" - IL-SEM study) - 2016

Research projects:

Design of PEM (low temperature) fuel cell electrocatalysts with enhanced electrochemical activity

*In collaboration with Department for Materials Chemistry (D10), Department of analytical Chemistry (D4) and Mebius d.o.o.

In the world of nanocatalysts further increase of oxygen reduction reaction activity and stability of platinum based electro-catalysts demands precise architecture on the atomic level. Two samples of PtCu3 nanoparticles embedded on a graphitic carbon support are carefully prepared with identical initial composition, particle dispersion and size distribution, yet with different degrees of structural ordering. The partially ordered structure (Pm3-m) exhibits and retains significantly higher (20–30%) specific activity compared to the fully disordered sample. For the first time the enhancement effect of structural ordering is systematically demonstrated. This new finding provides opportunity to further increase low-temperature polymer electrolyte membrane fuel cells efficiency and thus assist it in becoming more competitive with conventional combustion powered systems that are limited with theoretically less efficient Carnot cycle.

* Interested reader is invited to read our article

** Interested reader is also invited to read our new article

*** Interested reader is also invited to read our 2^nd new article

Design of PEM (low temperature) fuel cell electrocatalysts with enhanced electrochemical stability

^{*In collaboration with Department for Materials Chemistry (D10) and Department of analytical Chemistry (D4)}

Typical PEM fuel cell electrocatalysts like platinum based nanoparticles deposited on high surface area carbon are prone to stability issues. Pt tends to dissolve, Pt-alloy selectively leaches less noble metal and carbon corrodes. By doping PtCu₃ nono-alloy wit 1 % of gold dealloying of copper and carbon. corrosion are inhibited.

*Interested reader is invited to read our article

Design and understanding of PEM (low temperature) electrolyzer electrocatalysts with enhanced electrochemical performaces

*Interested reader is invited to read our article

A process for recycling of noble metals (Pt, Pd, Rh, Au, Ru, Ir, Os, Ag) by alternatively employing oxidative and reductive conditions inducing dissolution (leaching)

* In collaboration with Electrocatalysis group at Max-Planck-Institut für Eisenforschung GmbH and Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (Erlangen, Germany)

Platinum and other PGMs are very precious and scarce metals and are known to have excellent resistance to corrosion. Thus it is very difficult to leach them. For instance Pt only effectively dissolves at extreme conditions like in boiling aqua regia; a hazardous mixture of concentrated nitric and hydrochloric acid. We have achieved a complete dissolution of platinum black powder in low concentrated acid (0.3 M) at room temperature by exchanging between oxidative and reductive gasses. Our completely new concept of dissolving platinum utilizes the so-called transient dissolution mechanism that is triggered by the change of Pt oxidation state. Control over electrochemical surface potential is obtained only by exposing Pt suspension to appropriate gasses, importantly, without using any external electric current or electrodes. This enables recycling of unconducive materials like ceramic based catalytic converts.

*German patent application no. DE 10 20 15 118 279.3.

* Interested reader is invited to read our article

Development of advanced electrochemical characterisation tools:

Identical Location Electron Microscopy

*In collaboration with Laboratory for Materials Chemistry (L-10)