Over the coming decades, human society has to transition from being dependent on fossil fuels to renewable energy sources. However, renewable energy sources bring with them several inherent problems that need to be solved to integrate them into our society. The power supply of renewable energy sources is intermittent and does not match the global energy demand, necessitating the need for energy storage to bridge the gap. Additionally, the chemical industry relies heavily upon the usage of fossil fuels as chemical feedstocks that cannot be directly replaced by (electrical) renewable energy. Electrochemical CO2 reduction to these synthetic fuels and chemicals provides a promising approach to both these problems. However, finding a suitable catalyst for this electrochemical reaction has proven difficult. So far, among the monometallic transition metals, only copper has been shown to actively reduce CO2 into the desired synthetic fuels and chemicals. Unfortunately, these reactions take place at high overpotentials and unselectively. Alloying different metals together provides an elegant way to find new promising catalyst materials for the electrochemical reduction of CO2 to synthetic fuels and chemicals. This thesis investigates different aspects of bimetallic electrochemical CO2 reduction to synthetic fuels and chemicals....@en

In this study, we experimentally screen a promising class of intermetallic alloys for the electrochemical reduction of CO₂ toward hydrocarbon products. Based on previous DFT-based screening papers, combinations of strongly CO-binding metals such as iron, cobalt, and nickel with weakly CO-binding metals such as gallium, aluminium or zinc were selected as potentially promising catalytic materials. Despite the challenging production of these alloys, we report a general two-step synthesis method for intermetallic alloys and discuss the specific synthesis conditions that must be taken into account when synthesising these materials. After their synthesis, we use a recently developed differential electrochemical mass spectrometry (DEMS) setup to rapidly quantify the CO₂ reduction products over a range of potentials. Almost all newly developed intermetallic catalysts are shown to produce methane and ethylene, while the CoSn catalyst showed higher selectivity towards formate production. However, all tested catalysts mostly produced hydrogen and only reduce CO₂ to a small extent, despite the favourable computational screening results. We discuss possible reasons for this discrepancy and outline a more holistic approach for linking future DFT studies with experiments.

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Most research into electrochemical CO2 conversion focusses on improving electrode materials, but neglects the role of the electrolyte. We show the buffer influence on the selectivity of a bimetallic gold–palladium electrode in an effort to elucidate observed inconsistencies between different studies. While hydrocarbons are produced in the phosphate buffer, they remain absent in the bicarbonate buffer, showing that the electrolyte choice plays a crucial role in the selectivity of the electrode.@en

Electrochemical carbon dioxide reduction to multi-carbon products such as ethylene and ethanol is a promising method to store electricity in chemical bonds and produce bulk chemicals from CO2. Simultaneous consideration of processes taking place at the molecular scale, electrolyser scale, and the process scale is crucial to efficiently move towards commercialization and avoid optimizing for unrealistic operating conditions. This chapter summarizes the relevant considerations at each vantage point and reviews the latest developments in CO2 reduction toward multi-carbon products at different scales.@en