Rational Tuning the Proton Conductivity and Stability of Hydrogen-Bonded Organic Frameworks

Lin Xu; Mengyu Dang; Fengfan Yang; Feifan Lang; Beibei Li; Linfeng Liang; Jiandong Pang; Xian-He Bu

doi:10.1021/acs.inorgchem.4c02575

Rational Tuning the Proton Conductivity and Stability of Hydrogen-Bonded Organic Frameworks

Inorg Chem. 2024 Sep 23;63(38):17747-17754. doi: 10.1021/acs.inorgchem.4c02575. Epub 2024 Aug 29.

Authors

Lin Xu¹, Mengyu Dang², Fengfan Yang³, Feifan Lang¹, Beibei Li², Linfeng Liang³, Jiandong Pang¹, Xian-He Bu^{1

4}

Affiliations

¹ School of Materials Science and Engineering, Smart Sensing Interdisciplinary Science Centre, Nankai University, Tianjin 300350, China.
² Henan Key Laboratory of Polyoxometalate, College of Chemistry and Molecular Science, Henan University, Kaifeng, Henan 475004, China.
³ Institute of Crystalline Materials, Shanxi University, Taiyuan 030006, China.
⁴ State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.

PMID: 39207922
DOI: 10.1021/acs.inorgchem.4c02575

Abstract

In the development of proton conductors, it is crucial to regulate proton conduction pathways and enhance structural stability. In this study, we designed and constructed three hydrogen-bonded organic frameworks (HOFs), namely, NKM-HOF-9, NKM-HOF-10, and NKM-HOF-11, with different dimensional hydrogen-bonding pathways using 4,4'-sulfonyldibenzoic acid and various bases. They are cost-effective and easy to synthesize, allowing for their large-scale production at room temperature. By purposefully altering the ammonium ions, we achieved enhancements in the conductivity and stability of these HOFs. Proton conductivity studies at different humidities and temperatures revealed that at 85 °C and 98% relative humidity, the proton conductivity of NKM-HOF-10 reached 1.7 × 10^-3 S cm^-1, surpassing that of NKM-HOF-9 by 1 order of magnitude. This improvement was accomplished by increasing the number of proton donors from the base, which resulted in a transition of the hydrogen bond network from discontinuous to continuous, thereby enhancing the proton conduction performance. Moreover, stability tests showed that raising the base's pK_a could improve the stability of these frameworks. NKM-HOF-11, which features the highest pK_a, demonstrated superior stability by maintaining its structural integrity even at 450 °C.