Oregano Biomass as a Support for the Biosynthesis of Non-Precious Metal Catalysts

The energy production through fossil fuels and industrial processes has led to a crisis in energy pollution, being the main cause of greenhouse gas emissions responsible for climate change. One of the alternatives to reduce the environmental consequences associated with rising temperatures, sea level rise, and ocean acidification is the reduction of fossil energy consumption. Several alternatives are being explored to address this problem. One of these options is the use of fuel cells. Fuel cells provide a solution by generating energy from chemical reactions that result in the release of water vapor. The two principal reactions in these devices are the Hydrogen Evolution Reaction (HER) and the Oxygen Reduction Reaction (ORR). Both reactions require the use of catalysts for high performance and efficiency. The most widely used and efficient catalyst known is platinum. However, platinum and other efficient precious metals required as catalysts for these reactions are costly and scarce on the planet, highlighting the urgent need to develop non-precious metal catalysts.<br/>This project focuses on the development of non-precious metal catalysts for fuel cell fabrication using titanium dioxide as a support material for metal oxides, specifically targeting the ORR occurring at the cathode, since the HER occurring at the anode is a well-studied and understood reaction. Nevertheless, the ORR faces limitations regarding its dependency on costly catalysts and slow reaction kinetics, which impacts reaction performance.<br/>To address this, titanium dioxide is utilized due to its high chemical and thermal stability, large surface area, abundance, and semiconductor properties, making it an alternative for supporting the development of non-precious metal catalysts. Additionally, biotemplated titanium dioxide was synthesized using oregano biomass as a template for controlled particle growth, inducing the formation of a titanium dioxide chain that protects the catalyst from degradation. Particles were synthesized through the sol-gel method and characterized based on their size, chemical composition, and crystallinity. The analysis included data from X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR) , and X-ray photoelectron spectroscopy (XPS).<br/>The results for the iron-doped samples were then compared with those from biotemplated and non-biotemplated controls. Preliminary results indicate that the use of biomass as a mold affects the color, particle size, and crystallinity of the synthesized materials.