BSc Physics and Chemistry, University of Limpopo, Polokwane, 2010

BSc Honours Chemistry, University of Limpopo, Polokwane, 2011

MSc Chemistry, Rhodes University, Grahamstown, 2013

P. Modisha, E. Antunes and T. Nyokong. Photodegradation of Orange-G using zinc-octacarboxyphthalocyanine supported on Fe3O4 nanoparticles. Journal of Molecular Catalysis A: Chemical 380 (2013) 131-138.

P. Modisha, E. Antunes and T. Nyokong. Photophysical properties of zinc tetracarboxy phthalocyanines conjugated to magnetic nanoparticles. Journal of Nanoscience and Nanotechnology. 2015; 15(5):3688-96.

P. Modisha and T. Nyokong. Fabrication of phthalocyanine-magnetite hybrid nanofibers for degradation of Orange-G. Journal of Molecular Catalysis A: Chemical 381 (2014) 132-13.

P. Modisha and D. Bessaravbov. Electrocatalytic process for ammonia electrolysis: A remediation technique with hydrogen co-generation. Intenational Journal of Electrochemical Science 11 (2016)

P. M. Modisha, J. H.L. Jordaan, A. Bosmann, P. Wasserscheid, D. Bessarabov. Analysis of reaction mixtures of perhydro-dibenzyltoluene using two-dimensional gas chromatography and single quadrupole gas chromatography: 43 (2018) 5620-5636.

P.M. Modisha, C.N. Ouma, R. Garidzirai, P. Wasserscheid, D. Bessarabov. The Prospect of Hydrogen Storage Using Liquid Organic Hydrogen Carriers. Energy & Fuels. 2019;33(4):2778-96.

P. Modisha, P. Gqogqa, R. Garidzirai, C.N. Ouma, D. Bessarabov. Evaluation of catalyst activity for release of hydrogen from liquid organic hydrogen carriers. International Journal of Hydrogen Energy. 2019 Aug 13:44 (39):21926-35.

Evaluation of perhydrodibenzyltoluene dehydrogenation parameters and durability over noble metal catalysts for hydrogen production

Dibenzyltoluene (DBT) based liquid organic hydrogen carriers (LOHC) system has numerous advantages over conventional hydrogen storage systems. Most importantly, hydrogen storage and transport in the form of LOHC systems enables the use of the existing infrastructure for fuel. From a thermodynamic point of view, hydrogen storage in LOHC systems requires an exothermic hydrogenation step and an endothermic dehydrogenation step. Interestingly, hydrogenation and dehydrogenation can be carried out at the same temperature level. Under high hydrogen pressures (typically above 20 bar as provided from electrolysis or methane reforming), LOHC charging occurs and catalytic hydrogenation takes place. Under low hydrogen pressures (typically below 5 bar), hydrogen release from the LOHC system takes place. Since hydrogenation reaction is not challenging, understanding the course of the dehydrogenation reaction is important for catalyst and process optimization. Therefore, reliable and exact methods to determine the degree of dehydrogenation (DoD) and to analyse reaction mixtures are important. Possible techniques are: comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (2D-GC-TOF-MS) and single quadrupole-mass spectrometry gas chromatogram system (GC-SQ-MS). 1H NMR and GC-SQ-MS are employed as additional analytical techniques for validation. Furthermore, the effects of temperature, Pt metal loading, bimetallic catalyst (Pt-Pd) and Sn as a promoter are investigated for dehydrogenation perhydrodibenzyltoluene (H18-DBT). The properties of the catalysts employed are characterised using Brunauer–Emmett–Teller (BET), temperature-programmed reduction (TPR), CO pulse chemisorption and transmission electron microscopy (TEM). In addition, the amount of H2 charging and discharging cycles the LOHC material can tolerate will be investigated using both hydrogenation and dehydrogenation systems.

Supervisors: Dr. Dmitri Bessarabov