@article{PRASETYA2024115713,

title = {Investigation of the free-base Zr-porphyrin MOFs as relative humidity sensors for an indoor setting},

author = {Nicholaus Prasetya and Salih Okur},

url = {https://www.sciencedirect.com/science/article/pii/S0924424724007076},

doi = {https://doi.org/10.1016/j.sna.2024.115713},

issn = {0924-4247},

year  = {2024},

date = {2024-10-16},

urldate = {2024-01-01},

journal = {Sensors and Actuators A: Physical},

volume = {377},

pages = {115713},

abstract = {Maintaining optimal relative humidity is paramount for human comfort. Therefore, the utilization of quartz crystal microbalance (QCM) as a relative humidity sensor platform holds significant promise due to its cost-effectiveness and high sensitivity. This study explores the efficacy of three free-base Zr porphyrin metal-organic frameworks (MOFs) - namely MOF-525, MOF-545, and NU-902 - as sensitive materials for QCM-based relative humidity sensors. Our extended experimental findings reveal that these materials exhibit notable sensitivity, particularly within relative humidity ranges of 40–100 %. However, we observe potential irreversible adsorption sites within the MOF-545 framework, hindering its ability to revert to its initial state after prolonged exposure. In light of this observation, we conduct periodic cycling experiments at relative humidity levels of 40–70 % to evaluate the measurement repeatability and feasibility of these sensors for indoor applications. Interestingly, the periodic cycling study demonstrates that MOF-545 shows promising repeatability, positioning it as a strong contender for indoor relative humidity sensing. In contrast, MOF-525 may necessitate extended desorption time, and NU-902 displays diminished sensitivity at low relative humidity levels. Nevertheless, a preliminary treatment of the MOF-545 QCM sensor may be necessary to address irreversible adsorption sites and uphold measurement repeatability, as only reversible adsorption sites are currently accessible. This study underscores the potential of MOF-based QCM sensors for effective relative humidity monitoring in indoor environments, thus facilitating improved comfort and environmental control.},

keywords = {Adsorption, QCM Sensor SiO2, QCM sensors, Relative humidity, SiO2, Zr-porphyrin metal-organic framework},

pubstate = {published},

tppubtype = {article}

}