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We developed α-alumina catalyst supports using sugars as templates. These supports had significantly larger surface areas than commercially available alternatives, which is beneficial for catalytic applications. We demonstrated that pure α-alumina is essential for achieving high selectivity toward ethylene oxide, a valuable precursor used in products such as antifreeze and plastics.

Silver nanoparticles were deposited onto these supports to investigate how their size and distribution influenced catalyst performance. We found that not only the particle size matters, but especially the ratio between the active silver surface area and the support surface area. This ratio determines how efficiently ethylene is converted into ethylene oxide and how much of the undesired side-product, COâ‚‚, is formed.

We also examined the effect of so-called promoters, such as rhenium and alkali metals (such as lithium, sodium, and cesium). Rhenium improved selectivity and lowered the overall catalytic activity but led to unwanted side reactions when combined with ethyl chloride, a commonly used gaseous promoter. In contrast, alkali species–particularly cesium–were effective in suppressing these side reactions, even at higher conversions.

This research highlights the importance of the composition and balance of all components in a catalyst. By carefully combining the support, silver, and promoters, we can develop more efficient and selective catalysts for the industrial production of ethylene oxide.