The research group Applied Electrochemistry & Catalysis (ELCAT) of professor Tom Breugelmans belongs to the Faculty of Applied Engineering and mainly focuses on electrochemistry. The core research activities within ELCAT are related to the development of state-of-the art electrochemical reactors and catalysts, with a view towards large-scale industrial development in the field of industrial electrification, in a green and sustainable way to ultimately replace the traditional chemical processes. The scope there is to improve controllability, flexibility and energy efficiency of the reactions through electrocatalyst and reactor design. This research can thus be subdivided in three main topics, which are interrelated: electrocatalysis, electrosynthesis and electrochemical reactor engineering.
From those research topics, two major aspects of the identity as a group clearly come to the surface: industrial application and green chemistry. Up to date, ELCAT mainly focused on the synthesis, characterization and application of supported (bi)metallic nanoparticles for different electrochemical applications with a focus on studying selectivity, activity and stability. It is our hope that by working on the different levels from the (electro)catalyst to the actual reactor, future industrial processes can be based on the environmentally more friendly electrochemical approach, replacing the conventional batch chemical processes.
Moving towards a decarbonized economy, the ambition to decouple industrial processes from fossil-fuel-derived energy sources will inevitably pass through the exploitation of renewable energy sources such as wind, water and sun. Chemical manufacturing is nowadays based on thermochemical processes which are highly energy-demanding, requiring large amounts of heat. Electrochemical processes represent the most promising green alternative to the chemical methods, especially thanks to the fact that redox reactions constitute the larger fraction of the manufacturing of chemicals.
Electrochemical synthesis allows the direct transformation of clean electricity, derived from renewable energy sources, into chemical energy, resulting in emission-free processes. In addition to this, the electrochemical synthesis of organic molecules also offers a big opportunity for improved efficiency and access to untapped reaction pathways. In fact, electrosynthetic routes, being based on the transfer of electrons at a potential that is specific for the electro-active group of the organic molecule, can be employed for potential-controlled electrolysis to generate targeted products in fewer steps, producing less waste, using cheaper reagents and requiring less auxiliaries.Moreover, electrochemical technologies often allow an easier scale-up than non-electrochemical ones since they can be conducted in mild conditions while using electricity as redox reagent and driving force for the reaction. At ELCAT we investigate electrosynthetic routes to produce value-added chemicals from aldols’ condensation reactions, organic halide reduction, intramolecular ring formation reactions and sugars electrooxidation.
ELECTROCHEMICAL REACTOR ENGINEERING
In the domain of electrochemical reactor engineering ELCAT focuses on development and optimisation of electrochemical reactors. Investigations in this research domain require a combined approach of know-how on (1) reactor design, (2) electrochemical analysis techniques, (3) electrocatalysis and (4) electrochemical synthesis.
Research efforts are focused on several types of electrochemical flow reactors: filter press type, capillary gap, parallel plate, 3D electrodes, etc. The most important design parameters under investigation are current and potential distribution, yield, selectivity, ohmic drop and electrolyte flow rate. Reactors are developed for electrochemical processes of industrial significance. The reactor structures have dimensions in the range of 0.1 mm to 500 mm. Chemical reactions occur continuously through these microstructures and can even be upscaled to yield metric tons of product per hour, therefore making the technology also suitable for large-scale commercial production. These electrochemical reactors possess some fundamental benefits, including selectivity, reliability, rapid mixing, effective heat exchange, minimal reagent and solvent volumes, speed, safety, easy process control and automation, simple scale-up, improved sustainability, reduced waste, and cost-effectiveness. In addition they also allow to undertake certain, often hazardous, reactions that are not possible in a batch reactor.
To facilitate this research topic, the ELCAT lab is equipped with several modular reactor setups that can be used to test both commercial and in-house designed reactors with varying dimensions. Flow rates as low as 1 µL/h and up to several L/h can be applied and the reactor temperature can be varied from -20°C to 300°C. The designed reactors can be constructed at the ELCAT facilities using a variety of specialised equipment such as a CNC milling robot, lathes and 3D printing. A wide range of materials can be used such as polymers (PEEK, PTFE, COC, PMMA, PC, POM, …) and metals (aluminium, copper, titanium, stainless steel, …).
Electrochemistry allows for a manifold of reactions to proceed on a laboratory or industrial scale under ambient conditions. At the same time, it benefits from a relatively high energy efficiency and selectivity, which can be tuned towards the desired product by adapting the operating potential and/or the electrocatalyst. The major drawback of electrochemical activation is the large overpotential which is required for many of these processes. In order to reduce those large overpotentials, we thus need a well suited electrocatalyst. A lot of attention has been devoted to develop electrocatalytic processes, either by utilizing homogeneous redox catalysts (e.g. metal complexes, aromatic mediators) or by using heterogeneous electrocatalytic materials (e.g. bulk metals, metal nanoparticles or core-shell nanoparticles).
In order to synthesize industrially applicable electrocatalysts, the surface to volume ratio has to be increased drastically. Therefore, the application of nanoparticles on a conductive and inert supporting material is frequently used. The main topic within the electrocatalysis research at the ELCAT research group is focused on the influence of the nanoparticle morphology on the electrochemical mechanism and activity. Furthermore, a lot of effort is put into the synthesis of novel catalysts which are more stable, while maintaining their state-of-the-art selectivity and productivity. Additionally, the influence of the supporting material on the electrochemical performance is also being investigated.