Performance evaluation of a newly developed transition metal-doped HZSM-5 zeolite catalyst for single-step conversion of C₁-C₃ alcohols to fuel-range hydrocarbons

This study investigated the performance of metal-doped HZSM-5 catalysts in the conversion of low alcohols to hydrocarbons (LATH). Catalysts, including unmodified HZSM-5 and metal-modified (Ni, Fe, and Co) HZSM-5, were evaluated at 350 and 400 °C with space velocities of 7 and 12 h⁻¹ for LATH conversion. Characterisation techniques such as XRD, FTIR, SEM-EDS, PSD, N₂ adsorption, and TGA-DTA were employed. The characterisation results showed the successful metal incorporation in the HZSM-5 support catalyst. The overall evaluation of catalyst performance for LATH conversion revealed that the metal-doped catalysts showed a clear preference for liquid hydrocarbons with >99% average low alcohol conversion compared to the unmodified catalysts. In particular, Co/HZSM-5 and Fe/HZSM-5 showed a considerable preference for C₅-C₈ (62.81% and 54.95%), while Ni/HZSM-5 improved the synthesis of C₉-C₁₂ (11.40%), C₁₂⁺ (20.91%) and BTX (7.01%). The study on coke deposition indicated that Ni/HZSM-5 exhibited stability with minimal coke formation, while Co/HZSM-5 experienced higher coke deposition and deactivation tendencies in MTH and ETH conversions, respectively. Co/HZSM-5 exhibited the lowest weight loss, whereas Fe/HZSM-5 showed lower stability in PTH conversion. Notably, Ni/HZSM-5 demonstrated remarkable stability and performance in LATH conversion. These findings contribute to the advancement of catalysis and the transition towards a sustainable energy future.