In Situ Thermal Conductivity Measurement of Single-Crystal Zeolitic Imidazolate Framework‑8 by Raman-Resistance Temperature Detectors Method

The thermal conductivity measurement of metal–organic frameworks (MOFs), which plays an important role in thermal management of MOF-based gas separation, storage, and thermal energy conversion (e.g., adsorption heat pumps), has been a challenging task for decades. However, the direct thermal conductivity measurement of a single-crystal MOF is currently limited by their small crystal sizes, since no sophisticated approach has ever been reported. In this study, the Raman-resistance temperature detectors (Raman-RTDs) method was developed for in situ measuring of the thermal conductivity of single-crystal ZIF-8, whose system error resulting from the thermal contact resistance between sample and RTDs can be eliminated. According to the dependence of thermal resistance of MOF crystals on the laser spot location, the thermal conductivities of polycrystalline and single-crystal ZIF-8 were derived to be 0.21 ± 0.03 and 0.64 ± 0.09 W/(m·K), respectively. The proposed in situ thermal conductivity measurement method may be further extended to other types of microscale particles.