Yohannes Kiros
Senior researcher, Docent / Forskare förste, Docent
Email:
yoki@ket.kth.se
Phone: +468 790 8242
Address: TEKNIKRINGEN 42, Level 6
Room: 683
Research field
Electrocatalytic materials incorporated into gas diffusion electrodes (GDEs) are of great importance for electrochemical energy conversion and storage in fuel cells, metal-air batteries and battery systems, electrolyzers and other industrial processes. For example, oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER), either for the demanding reaction with its complex mechanisms or for the facile reactions for the proper functioning of the performance/stability characteristics need active materials for electrocatalysis to take place. Furthermore, combination with supports for dispersion, promotion of high surface and porosity as well as conductivity together with the design aspects of the GDEs, especially for the low and medium-temperature fuel cells and other electrochemical applications can significantly enhance the outcome in the form of high current or power densities with lower overvoltages. The dependence on noble metal catalysts or their alloys, albeit in low loadings in many electrochemical systems, especially for application in fuel cells or electrolyzers has so far hampered commercialization due to their high costs, instability and accessibility globally. The research approach is mainly multifaceted, viz. preparation of highly functional materials from the transition d-metals with additives and/or promoters as heterogeneous catalysts, integration of the same in a robust electrode configuration and physicochemical characterization of the electrocatalytic materials using various analytical tools.
Furthermore, work on heterogeneous materials as alternative to homogeneous catalysts, presently used on wide-scale for biodiesel production from vegetable oils (edible and non-edible) is challenging in a three-phase system, where the presence of free-fatty acids has to be addressed. Different parameters including the type and structure of the catalyst that affect the yield of biodiesel have to be optimized in order to find application. Biofuels in the form of ethanol through direct fermentation (DF), simultaneous saccharification (SSF), separate hydrolysis and fermentation (SHF) and enzymatic method of biomass residues is also another area of interest. Unit operation systems such as adsorption and absorption is also another area of interest, where adsorbents can be prepared from different precursors.
Projects
Innovative Iron-Air Battery
The project "Innovative iron-air battery", which is a joint project between KTH and SU addresses research and development on the iron/air battery in order to strengthen and build competencies in innovation, system approach and knowledge of materials within the battery technology. The combination of an iron anode and an air cathode is a reliable solution that could handle large scale solutions, considering the volume and accessibility of the materials and reactants. The iron anode despite its high energy density, long cycle life, cheap and minor environmental footprint has not yet receieved much attention. It is a primary goal of this project to develop functionalized iron/air batteries on a "Höganäs process", where porous and spongy iron particles are produced and tailormade for the purpose and progress of this project.
Bioconversion processes for liquid fuels production
This project is a joint project between KTH and UMSS with SIDA funding, addressing research and development for the production of energy in the form of biodiesel and bioethanol. The two-pronged approach filling the energy gap, especially for the transportation sector in Bolivia is of importance impacting on self-sufficiency with sustained socio-economic development.
Heterogeneous catalysts for the transesterification reaction are essentially a surface and chemical phenomena, where the reaction mixture constitutes a three-phase system, i.e., oil/methanol/catalyst. Therefore, the study of catalytic processes involves the surface properties of the solid, surface diffusion, reaction kinetics, selectivity and chemical properties.
On the other hand, research on ethanol production will be carried out. The use of second generation ethanol feedstock is also important in increasing agricultural productivity gains and reduce the amounts of biomass residues either by direct frementation, simultaneous Saccharification and fermentation or enzymatic route.
Publications
- Alagar Raj Paulraj, Yohannes Kiros,Mats Göthelid, Malin B. Johansson, NiFeOx as bifunctional electrocatalyst for oxygen reduction (OR) and evolution (OE) reaction in alkaline media. Catalysts, 8 (2018) 328.
- Alagar Raj Paulraj, Yohannes Kiros, La0.1Ca0.9MnO3/Co3O4 for oxygen reduction and evolution reactions (ORER) in alkaline electrolyte, J Solid State Electrochem., (2018)
- E. Menya, P.W. Olupot, H. Storz, M. Lubwama, Y. Kiros, Production and performance of activated carbon from rice husks for removal of natural organic matter from water: A review, Chem. Eng. Research & Design, 129 (2018) 271-296.
- Inna L. Soroka, Nadezda V. Tarakina, Anton Hermansson, Lukas Bigum, Rickard Widerberg, Mikael S. Andersson, Roland Mathieu, Alagar R. Paulraj, Yohannes Kiros, Radiation-induced synthesis of nanoscale Co- and Ni- based electro-catalysts on carbon for oxygen reduction reaction, Dalton Trans. 46 (2017) 9995-10002.
- Alagar Raj Paulraj, Yohannes Kiros, Björn Skårman, Hilmar Vidarsson, Core/Shell structure nano-iron/iron carbide electrodes for rechargeable alkaline iron batteries, J Electrochem Soc, 164 (2017) A1665-A1672
- J-P. Spets, P. Kanninen, T. Kallio, J. Selkäinaho, Y. Kiros, K. Saari, M. Larmi, Towards and efficient direct glucose anion exchange membrane fuel cell system with several electro-oxidation units, Int. J. Electrochem. Sci., 12 (2017) 3697-3708.
- J. L. Solis, A. L. Berkemar, L. Alejo, Y. Kiros, Biodiesel from rapeseed oil (Brassica napus) by supported Li2O and MgO, Int J Energy Environ Eng, 8 (2017) 9-23
- J. L. Solis , Y. Kiros, L. Alejo, Calcium and tin (IV) oxides for heterogeneous transesterification of Babassu oil (Attalea speciosa), J Environ Chem Eng., 4 (2016) 4870-4877.
- Nima Fotouhi Tehrani, Javier. S. Aznar, Yohannes Kiros, Coffee extract residue for production of ethanol and activated carbon, J. Cleaner Prod, 91 (2015) 64.
- T. Eriksson, Y. Kiros, Temperature swing adsorption device for oxygen-enriched air, J. Cleaner Prod, 76 (2014) 174.
- S. Marini, P. Salvi, P. Nelli, R. Pesenti, M. Villa, Y. Kiros, Stable and inexpensive electrodes for the hydrogen evolution reaction, Int. J. Hydrogen Energy, 38 (2013), 11484.
- S. Marini, P. Salvi, P. Nelli, R. Pesenti, M. Villa, Y. Kiros, Oxygen evolution in alkali with gas diffusion electrodes, Int. J. Hydrogen Energy, 38 (2013) 11496.
Link to DiVA page
kth.diva-portal.org/dream/info.jsf
Teaching activities
Undergraduate
Engineering Chemistry (KE1140)
Graduate courses
Experimental Process Design (KE2195)