10.1021/acs.cgd.6b01564.s001 Maeva Borel Maeva Borel Mathias Dodin Mathias Dodin T. Jean Daou T. Jean Daou Nicolas Bats Nicolas Bats Bogdan Harbuzaru Bogdan Harbuzaru Joël Patarin Joël Patarin SDA-Free Hydrothermal Synthesis of High-Silica Ultra-nanosized Zeolite Y American Chemical Society 2017 high-silica ultra-nanosized zeolite Y crystals display synthesis protocol High-Silica Ultra-nanosized Zeolite Y hydrocracking processes crystallization conditions microsized counterparts zeolite Y nanocrystals textural properties zeolite Y SDA-Free Hydrothermal Synthesis 30 nm S BET gel composition V micropore physicochemical properties template-free medium aluminum ratio silica source 2017-02-07 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/SDA-Free_Hydrothermal_Synthesis_of_High-Silica_Ultra-nanosized_Zeolite_Y/4659055 Despite having been used in hydrocracking processes for decades, zeolite Y is still nowadays the subject of intense research aiming at improving its physicochemical properties. Here, and for the first time, the synthesis of zeolite Y nanocrystals prepared in organic template-free medium, featuring both extremely reduced dimensions (mean diameter below 30 nm) and a high silicon to aluminum ratio (Si/Al ≈ 2.2), is reported. The singularity of the protocol lies in the progressive adding of a silica source during synthesis combined with the use of prolonged aging times. These high-silica ultra-nanosized zeolite Y crystals display excellent textural properties (<i>V</i><sub>micropore</sub> = 0.33 cm<sup>3</sup>/g and <i>S</i><sub>BET</sub> = 830 m<sup>2</sup>/g), comparable to their microsized counterparts. In this work, the extensive study of the influence of various parameters (<i>i.e.</i>, gel composition, aging time, and crystallization conditions) intended for the optimization of the synthesis protocol is also presented.