<![CDATA[The demand for high-quality fuel with a high-octane number or Research Octane Number (RON) continues to increase due to strict emission standards and the ban on lead-based additives. This study aims to develop a catalyst material based on Indonesian natural zeolites from Lampung (ZAL), Bayah (ZAB), and Tasikmalaya (ZAT) through pre-treatment optimization to obtain comparable mesoporous material properties with Mobil Composition of Matter No. 41 (MCM-41). This catalyst is designed for the isomerization process of n-hexane into iso-hexane as a model compound for light naphtha. The research focuses on utilizing Indonesian natural zeolite in combination with desilication techniques using NaOH and cetyltrimethylammonium bromide (CTAB) as surface directing agents. The catalyst is characterized by using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Surface Area Analysis (SAA), and Scanning Electron Microscopy (SEM) to identify the surface morphology of zeolite. XRD results show structural alteration in the low-to-high θ/2θ region with increasing NaOH concentration. XRF analysis reveals that the bulk Si and Al contents remain relatively stable (Si: 34.73-36.6 wt%; Al: 6.55-8.1 wt%), confirming that desilication occurs selectively at the crystal surface rather than altering the bulk composition. SAA data demonstrate substantial enhancement of textural properties, with the specific surface area increasing from 40.5 to 131.7 m²/g for ZAL, 36.5 to 134.9 m²/g for ZAT, and 46.9 to 101.0 m²/g for ZAB after 1.5 M NaOH treatment. SEM images reveal morphological changes from a defined crystalline texture to a more dispersed surface upon increasing NaOH concentration. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).]]>
