Congratulations to Dr. Mirjam E. de Graaf on a successful PhD defense, during which she defended her PhD thesis, supervised by Prof. Bert Weckhuysen and Dr Eline Hutter.
In her PhD thesis, Mirjam investigated light-activated materials (photocatalysts) that could break down harmful volatile organic compounds (VOCs) in indoor environments. With people spending up to 90% of their time indoors, creating healthy indoor environments has become essential for human health. VOCs, released during everyday activities such as cooking or from new furniture, can cause headaches, fatigue, and eye irritation.
Mirjam studied photocatalysts that could potentially be incorporated into wall paint to create air-purifying walls. She investigated Co₃O₄/TiO₂ photocatalysts for degrading indigo carmine dye under sunlight and LED light, demonstrating that a 1.4 wt% loading of Co₃O₄ on TiO₂ resulted in the highest activity. She moved on to gas-phase VOCs, examining acetone degradation under UV light using TiO₂/zeolite ZSM-5 hybrid photocatalysts with varying silicon-to-aluminum ratios. She found that the degradation reaction was primarily influenced by the intensity of UV light.
Additionally, Mirjam designed and developed a specialized gas chromatography-based setup capable of detecting VOCs at concentrations as low as 1 ppm in a batch-type reactor mimicking closed-off indoor spaces. Finally, she tested photocatalysts in actual wall paint applications, emphasizing the crucial need for testing materials in their final application context, as materials that showed activity in laboratory conditions often demonstrated a lack of activity when incorporated into paint.
Mirjam’s PhD thesis is available to read here.