Unraveling the Intrinsic Activity of Nanoparticles: A Journey Towards Selective CO₂ Electroreduction

The climate crisis poses an unprecedented threat to our planet, intensified by the increasing
release of greenhouse gases, particularly carbon dioxide (CO₂), into the atmosphere. As global temperatures rise, ecosystems suffer, and extreme weather events become more frequent, urgent action is required to lower CO₂ emissions and mitigate the impacts of global warming. Renewable energy sources offer a promising avenue for reducing our reliance on fossil fuels, but challenges remain in efficiently storing and distributing this energy.
This thesis explores the potential of catalysis in addressing the climate crisis, in the particular case of electrochemical CO₂ reduction. By converting CO₂ into high-value chemicals using renewable electricity, catalysis offers a pathway to both reducing atmospheric CO₂ levels and producing valuable products. Nanoparticles and clusters, with their high surface-to-volume ratio, emerge as key players in catalysis, offering enhanced efficiency and selectivity.
Through a series of meticulously conducted electrochemical experiments, this thesis investigates the catalytic performance of monometallic and bi-metallic nanoparticles, addressing challenges in experimental methodology and implementing setup enhancements to ensure robust results. Comprising nine chapters, the thesis begins by establishing and adjusting the experimental methodology, followed by presenting the obtained results and implications for future research. The main investigations focus on evaluating how nanoparticle size influences catalytic performance, particularly for gold and copper nanoparticles, alongside preliminary studies of bi-metallic systems. These results contribute to identifying the structural features of catalysts that yield high selectivity towards desirable products, including carbon monoxide, ethylene, and methane. The findings illuminate the intricate relationship between nanoparticle structure and catalytic activity.
The objective of this thesis is to enhance our comprehension of catalysis in CO₂ electroreduction, with a focus on designing efficient and selective catalysts to mitigate climate change. By conducting rigorous experimentation and comprehensive analysis, it provides a foundation for future research aimed at accelerating the transition to a carbon-neutral society.