doi:10.1021/acsanm.5c03130engPérez-Miana, MartaFernández de Luis, RobertoFidalgo-Marijuan, ArkaitzLi, JunyanMayoral, ÁlvaroCoronas, JoaquínHigh Pressure-Based Synthesis of Nanoporous Metal–Organic Framework ZIF-93 Giving Rise to a Phase for Proton ConductionART-2025-146294This study aims to develop a green, solvent-free synthesis of ZIF-93 (ZIF stands for zeolitic imidazolate framework) and to explore the formation of different phases. We report the solvent-free synthesis of a previously unreported nanoporous ZIF phase, ZIF-93_HP (HP referring to “high-pressure”), from zinc oxide using a dual high-pressure (150 MPa) and thermal (110 °C) method. The influence of key synthesis parameters, such as the amount of NH4NO3 promotor and reaction steps, was systematically investigated to maximize the conversion of ZnO into the intermediate ZIF-93_HP, while, in parallel, preventing its further conversion into nanoporous ZIF-93 phase. The material was extensively characterized by X-ray diffraction, thermogravimetry, electron microscopy and N2 and CO2 adsorption, which revealed insights into the structure, morphology and nanoporosity of ZIF-93_HP. ZIF-93_HP, with empirical formula of Zn(C5N2OH5)2·1.2(NH4NO3)·(H2O), is related to the previously reported ZIF-93 (Zn(C5N2OH5)2). Water washing of this phase led to the transformation into ZIF-93 and a significant increase in the BET specific surface area (from 4 to 181 m2/g). In addition, the presence of NH4+ and NO3– ions into its structure makes ZIF-93_HP proton conductor at room temperature and moisture conditions (3.76 × 10–3 S/cm), a property that decreases with increasing temperature due to dehydration. The discovery of ZIF-93_HP highlights the potential of the high-pressure, solvent-free synthesis as a powerful tool for the exploration of different ZIFs and reticular materials that are inaccessible through traditional solvothermal methods. As crystallization under solvent-free conditions is often influenced by nonthermodynamic equilibrium, this approach holds a great potential for expanding the material landscape by enabling the discovery of different phases and structures with unique properties, such as the promising proton conductivity demonstrated here.2025http://zaguan.unizar.es/record/16413210.1021/acsanm.5c03130http://zaguan.unizar.es/record/164132oai:zaguan.unizar.es:164132info:eu-repo/grantAgreement/ES/DGA/E13-23Rinfo:eu-repo/grantAgreement/ES/DGA/T68-23Rinfo:eu-repo/grantAgreement/ES/MCIU/RYC-2018-024561-Iinfo:eu-repo/grantAgreement/ES/MICIU/CEX2023-001286-Sinfo:eu-repo/grantAgreement/ES/MICIU/CNS2023-144346info:eu-repo/grantAgreement/ES/MICIU/PID2021-122940OB-C31info:eu-repo/grantAgreement/ES/MICIU/PID2022-138582OB-I00ACS APPLIED NANO MATERIALS 8, 43 (2025), 20713-20725byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess