Ag-Promoted ZrBEA Zeolites Obtained by Post-Synthetic Modification for Conversion of Ethanol to Butadiene

1,3‐Butadiene was synthesized from ethanol using zirconium‐containing zeolite beta (ZrBEA) catalysts doped with 1 wt % silver. The Zr was planted using post‐synthesis modification by dealumination of the parent zeolite followed by treatment with ZrOCl2 in a DMSO solution. FTIR and NMR spectroscopy were used to investigate the planting process by preparing materials with different Si/Al ratios and crystal sizes. The results showed preferential grafting of Zr to the terminal silanols present on the external surface of the zeolite crystals instead of incorporation of Zr into silanol nests. The grafting yielded highly accessible Zr(OSi)3OH open sites with high Lewis acidity, as confirmed by FTIR spectroscopy of adsorbed CO. These sites are shown to be extremely active for the conversion of ethanol to butadiene. Ag/ZrBEA catalysts prepared using the post‐synthesis method showed significant advantages compared with Ag/ZrBEA catalysts synthesized using a conventional hydrothermal procedure. The best catalyst performance in terms of butadiene formation rate (3 μmol g−1 s−1) was observed over Ag/Zr(3.5)BEA(75) (containing 3.5 wt % Zr), which had the smallest crystal size and the highest content of Zr open sites of the prepared catalysts. The Ag goes to Zeolites! Ag/ZrBEA (zirconium‐containing zeolite beta) catalysts prepared using a post‐synthesis method show significant advantages compared with Ag/ZrBEA catalysts synthesized using a conventional hydrothermal procedure. Parent AlBEA materials with different Si/Al ratios and crystal sizes are used to determine the best catalyst for the conversion of ethanol to butadiene.