Speaker:
Laura Milišić
Materials Research Laboratory,
University of Nova Gorica, Slovenia
Abstract:
The rising level of CO2 in the atmosphere is a primary environmental concern, significantly contributing to global warming and climate change. Converting CO2 into valuable chemicals, such as methanol, offers a promising approach to mitigate its impact, aligning with the goals of sustainability and circular carbon use. To understand CO2 conversion, highlighting reaction mechanisms and exploring the roles of thermal and photothermal conditions is necessary. The main catalytic system studied involves noble metals supported on mixed-metal oxides. The hydrogenation of CO2 to methanol occurs via the formate mechanism, where CO2 is directly hydrogenated to a formate intermediate, which then converts to methanol. This pathway is often preferred over the alternative reverse water-gas shift route, which initially reduces CO2 to carbon monoxide (CO). Emphasising the formate mechanism leads to higher methanol selectivity and prevents the formation of undesirable CO byproduct, thereby improving the overall efficiency of the process. While traditionally relying on thermal energy to drive the reaction, advanced catalytic systems are increasingly exploring photothermal strategies for improved efficiency. These photothermal methods, including both plasmonic phenomena in certain nanoparticles and non- plasmonic light absorption by semiconductor materials, offer unique ways to deliver energy to the reaction sites. Such light-driven activation can promote specific reaction pathways or lower activation barriers, thereby enhancing overall catalytic performance.
The mechanism may be influenced by the particular noble metal dispersion and the attributes of the support materials. Layered double hydroxides (LDHs) are highly versatile materials, widely employed as precursors for the fabrication of multifunctional catalyst supports. Their tunable composition, anion- exchange capacity, and structural flexibility allow for the co-incorporation of a broad range of metal cations, enabling precise control over catalytic properties. Upon calcination, LDH-derived mixed metal oxides exhibit high surface area, adjustable basicity, and well-dispersed active sites. The noble metals such as gold (Au) and palladium (Pd) can be introduced via ion exchange, ensuring uniform distribution and strong metal-support interactions.
The seminar will take place in hybrid mode
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