Remarkably enhanced stability of HZSM-5 zeolite co-modified with alkaline and phosphorous for the selective conversion of bio-ethanol to propylene

• Selective conversion of bio-ethanol to propylene was investigated on HZSM-5.
• Phosphorus modification can improve propylene selectivity and catalyst stability.
• Co-modifications with NaOH and phosphorus exhibit the best catalytic stability.
• Phosphorus modified HZSM-5 catalyst was deactivated by carbon deposition.

The effects of alkaline, phosphorous and dual alkaline-phosphorous modifications on the selective conversion of bio-ethanol to propylene over HZSM-5 zeolite catalysts were investigated. The results demonstrate that the doubly modified HZSM-5 zeolite catalyst offers higher propylene selectivity and remarkably improved catalytic stability than the parent and singly modified counterparts, which can be contributed to the formation of new mesoporous and decreased amount of strong acid sites induced by the alkaline treatment and phosphorous modification, respectively. The deactivation of the phosphorous and dual alkaline-phosphorous modified HZSM-5 zeolite catalysts was caused by carbon deposition but not by dealumination, which can be attributed to the enhanced hydrothermal stability of the framework aluminum by the modification of ZSM-5 zeolite with phosphorus.

Dual modifications with alkaline and phosphorous significantly enhanced the catalytic stability of HZSM-5 zeolite for the selective conversion of bio-ethanol to propylene.Figure optionsDownload high-quality image (88 K)Download as PowerPoint slide