The impact of preparation route on the performance of silver dodecatungstophosphate/β zeolite catalysts in the ethylene production

Abstract

Heteropolyacids and their salts comprise catalytic centers for the production of ethylene, one of the most important constituents in the chemical industry. The paper emphasizes different synthesis routes of hybrid materials consisting of dodecatungstophosphoric acid silver salt (AgPW) and β zeolite—stepwise wet impregnation, silver-exchange in β zeolite, and dry mixing of precursors. Composite preparation procedures induced minor effects on the weak acid sites, while strong acid sites were increased significantly. β/AgPW composites prepared by two-steps wet impregnation and ion-exchange procedures have strong acid sites content and total acidity higher in comparison to the pure AgPW salt and β zeolite. This is a result of precursors synergetic effect—cumulative strong acidic sites are generated in the presence of well-dispersed Keggin ions on the zeolite network. Composite samples with a higher content of strong acid centers exhibit higher conversion in the ethanol dehydration reaction, i.e., the ion-exchanged βAgPW sample has attained a conversion over 81%, while the wet-impregnated sample has a significant 86%. The distribution and presence of AgPW active phase are found to be crucial for both stable conversion and high selectivity results in ethylene production from ethanol, which is regarded as one of the most significant processes in environmental and sustainable industrial chemistry. Graphic abstract: [Figure not available: see fulltext.]