Browsing by Author "Bladergroen, Bernard J."

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    Ex-situ electrochemical characterization of iro2 synthesized by a modified Adams fusion method for the oxygen evolution reaction
    (MDPI, 2019) Felix, Cecil; Bladergroen, Bernard J.; Linkov, Vladimir
    The development of highly stable and active electrocatalysts for the oxygen evolution reaction (OER) has attracted significant research interest. IrO2 is known to show good stability during the OER however it is not known to be the most active. Thus, significant research has been dedicated to enhance the activity of IrO2 toward the OER. In this study, IrO2 catalysts were synthesized using a modified Adams fusion method. The Adams fusion method is simple and is shown to directly produce nano-sized metal oxides. The effect of the Ir precursor salt to the NaNO3 ratio and the fusion temperature on the OER activity of the synthesized IrO2 electrocatalysts, was investigated. The OER activity and durability of the IrO2 electrocatalysts were evaluated ex-situ via cyclic voltammetry (CV), chronopotentiometry (CP), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV).
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    The production of hydrogen through the use of a 77 wt% Pd 23 wt% Ag membrane water gas shift Reactor
    (Elsevier, 2016) Baloyi, Liberty N.; North, Brian C.; Langmi, Henrietta W.; Bladergroen, Bernard J.; Ojumu, Tunde V.
    Hydrogen as an energy carrier has the potential to decarbonize the energy sector. This work presents the application of a palladium-silver (PdeAg) membrane-based reactor. The membrane reactor which is made from PdeAg film supported by porous stainless steel (PSS) is evaluated for the production of hydrogen and the potential replacement of the current two stage Water-Gas Shift (WGS) reaction by a single stage reaction. The permeability of a 20 mm PdeAg membrane reactor was examined at 320 _C, 380 _C and 430 _C. The effect of continuous hydrogen exposure on the PdeAg membrane at high temperature and low temperature was examined to investigate the thermal stability and durability of the membrane. During continuous operation to determine thermal stability, the membrane reactor exhibited stable hydrogen permeation at 320 _C for 120 h and unstable hydrogen permeation at 430 _C was observed. For the WGS reaction, the reactor was loaded with Ferrochrome catalyst. The membrane showed the ability to produce high purity hydrogen, with a CO conversion and an H2 recovery of 84% and 88%, respectively. The membrane suffered from hydrogen embrittlement due to desorption and adsorption of hydrogen on the membrane surface. SEM analysis revealed cracks that occurred on the surface of the membrane after hydrogen exposure. XRD analysis revealed lattice expansion after hydrogen loading which suggests the occurrence of phase change from a-phase to the more brittle b phase.
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    Recovery of organic electrolyte solvents from spent perforated Li-ion cells using a low-temperature vacuum-assisted distillation process
    (Elsevier B.V., 2025) Tawonezvi, Tendai; Sinto, Anele; Zide, Dorcas; Bladergroen, Bernard J.
    Electrolyte solvent recovery is rarely addressed in current state-of-the-art lithium-ion battery (LiB) recycling processes, even though electrolytes are flammable, toxic, and hazardous. In conventional recycling processes, electrolytes typically evaporate or decompose uncontrollably during pre-treatment steps such as shredding, leading to both safety risks and environmental damage. To overcome these limitations, we investigated a controlled electrolyte solvent recovery process using mild-temperature vacuum distillation on perforated, intact batteries rather than shredded material. This method enabled safe handling and minimised uncontrolled emissions during pre-treatment. Analysis results demonstrate a successful 84 % recovery of the major electrolyte solvents, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), after 300 min of thermal-vacuum treatment at 110 °C and 80 mBar vacuum pressure. Decomposition products of Lithium Hexafluorophosphate (LiPF₆), which include hydrogen fluoride (HF) and phosphoryl fluoride (POF₃), were not identified in the exhaust gas, and the scrubber solution remained neutral during operation. These results demonstrate that thermal treatment below 110 °C is a non-complex, feasible, and environmentally friendly process for recovering electrolyte solvents prior to metal recovery, addressing a major gap in current LiB recycling processes.