The rapid global climate change associated with increasing planetary CO$_2$ levels is possibly one of the greatest challenges existing currently. In order to address this grave problem, a variety of solutions and approaches have been proposed. It is likely that a combination of these approaches would be required to solve the multi-dimensional problem of climate change. One potential approach to mitigate carbon emissions is the concept of a ‘Circular Carbon Economy’. This approach encompasses the concept of capturing carbon emissions and reusing the captured CO$_2$ to make fuels and chemicals using renewable energy. Use of fuels and chemicals manufactured via this approach would thus avoid ‘new’ CO$_2$ emissions and prevent the accumulation of additional CO$_2$ in the atmosphere as these products will be CO$_2$-neutral. The use of CO$_2$-neutral fuels would especially be beneficial as not only would it cause a significant impact on CO$_2$ emissions in terms of volume but also it would provide a way to store energy from intermittent sources like solar, wind etc. Furthermore, these fuels can be used without requiring a significant overhaul of the energy infrastructure.
One of the most promising routes for the synthesis of fuels and chemicals from CO$_2$ is via the thermal hydrogenation of CO$_2$ using multifunctional heterogeneous catalysis. Multifunctional catalysis refers to the combination of catalysts having different functionalities into a single reactor (one-pot). This catalytic route is a powerful tool for tuning the product distribution during a reaction and for enhancing the yield of target products.
Thus, this PhD Thesis describes the design of several multifunctional catalyst combinations which have been applied for producing various hydrocarbon products of interest from CO$_2$ ranging from light olefins, aromatics and fuel range paraffins. The catalyst combinations consisted of a metal/metal oxide and a zeolite and depending on the configuration used, enhanced the selectivity to target products. Various advanced characterization techniques have also been utilized in order to reveal the status of active species and the underlying reaction mechanism(s).
|Date of Award||Feb 2022|
|Original language||English (US)|
- Physical Sciences and Engineering
|Supervisor||Jorge Gascon (Supervisor)|
- CO2 Hydrogenation
- heterogeneous catalysis
- catalyst design