金屬有機骨架材料（Metal–organic frameworks, MOFs）是一種由金屬節點與有機小分子連接組合而成的奈米孔洞材料，其具有極高的比表面積、規律有序的孔洞以及可調控的結構和修飾能力，基於此近年來用作質子傳導材料受到廣泛關注。其中，鋯基金屬有機骨架材料（Zirconium-based MOFs, Zr-MOFs）因其具備良好的水穩定性、電氣絕緣特性，以及鋯節點上可參與質子傳導的羥基，被視為具潛力的質子導體材料。本研究以一種具水穩的二維Zr-MOF，ZrBTB（BTB = 1,3,5-tri(4-carboxyphenyl)benzene）作為平台，導入富含親水性官能基之氧化石墨烯（graphene oxide, GO）形成複合材料，探討不同製備方式與調控GO添加量對質子傳導表現的影響。分別以化學接枝法與物理混摻法製備MOF-GO複合材料。當GO添加量為1 wt% 時，化學接枝所得的ZrBTB–0.01GO於60 °C、99% 相對濕度（relative humidity, RH）下的質子傳導率為3.93 × 10−3 S cm−1，低於原始 ZrBTB與GO，歸因於GO上的羧酸根與ZrBTB的鋯節點進行配位，使得可參與質子傳導的親水的官能基數量減少，導致形成不連續的氫鍵網路。
相較之下，物理混摻法可有效提升複合材料之質子傳導表現。其中ZrBTB/0.01GO於60 °C、99% RH條件下的質子傳導率可達4.01 × 10−2 S cm−1，相應的活化能為0.28 eV。隨後調控GO在複合材料的比例後，在親水官能基數量與材料孔洞性取得平衡的ZrBTB/0.005GO展現最佳的質子傳導表現，於相同條件下的質子傳導率達1.03 × 10−1 S cm−1，對應的活化能僅有0.18 eV，這可歸因於物理混摻法較能保留ZrBTB與GO原有的親水性官能基與良好的吸水能力，形成較鬆散之二維片狀堆疊結構，有助於水分子吸附與連續氫鍵網路的建立。本研究結果顯示，適當的GO添加量與挑選合適的複合材料製備方法可有效的提升二維MOF/GO複合材料的質子傳導率。

A water-stable two-dimensional (2D) zirconium-based metal–organic framework (MOF), ZrBTB (BTB = 1,3,5-tri(4-carboxyphenyl)benzene), serves as a porous platform to integrate with graphene oxide (GO) in order to achieve ultrahigh proton conductivity (σ). Two synthetic methods, chemical grafting and physical blending, are used for preparing various nanocomposites composed of ZrBTB and GO. The porosity, morphology, and proton-conducting characteristics of these composites and both pristine materials are investigated. The nanocomposite obtained by the grafting method with a GO loading of around 1 wt%, ZrBTB–0.01GO, possesses coordination bonds between GO and the hexa-zirconium nodes of ZrBTB; such chemical grafting reduces the number of accessible –OH/–OH2 pairs on the MOF nodes. ZrBTB–0.01GO thus exhibits a worse proton-conducting performance, with a σ of 3.93 × 10−3 S cm−1 at 60 °C and 99% relative humidity (RH), compared to those of the pristine ZrBTB (1.57 × 10−2 S cm−1) and pristine GO (8.68 × 10−3 S cm−1), respectively.
In contrast, the physical blending method yields considerably higher proton conductivities and lower activation energies at the same GO loading, with ZrBTB/0.01GO exhibiting a σ of 4.01 × 10−2 S cm−1 at 60 °C and 99% RH and an activation energy of 0.28 eV. At an optimal GO loading, the resulting 2D nanocomposite, ZrBTB/0.005GO, can achieve an ultrahigh σ of 1.03 × 10−1 S cm−1 at 60 °C under 99% RH with a low activation energy of 0.18 eV. The findings here suggest that compared to the commonly reported chemical grafting method, the physical blending method is more advantageous for preparing proton-conductive 2D MOF-based nanocomposites with more accessible proton-relaying functional groups and thus better performance.

[1] K.-D. Kreuer, Proton Conductivity:  Materials and Applications, Chemistry of Materials, 8, 610–641, 1996.
[2] K.-D. Kreuer, S. J. Paddison, E. Spohr and M. Schuster, Transport in proton conductors for fuel-cell applications: simulations, elementary reactions, and phenomenology, Chemical Reviews, 104, 4637–4678, 2004.
[3] R. Williams, Proton circuits in biological energy interconversions, Annual Review of Biophysics and Biophysical Chemistry, 17, 71–97, 1988.
[4] C. Laberty-Robert, K. Valle, F. Pereira and C. Sanchez, Design and properties of functional hybrid organic–inorganic membranes for fuel cells, Chemical Society Reviews, 40, 961–1005, 2011.
[5] P. Colomban, Proton conductors and their applications: A tentative historical overview of the early researches, Solid State Ionics, 334, 125–144, 2019.
[6] M. Carmo, D. L. Fritz, J. Mergel and D. Stolten, A comprehensive review on PEM water electrolysis, International Journal of Hydrogen Energy, 38, 4901–4934, 2013.
[7] K. Zhang, X. Liang, L. Wang, K. Sun, Y. Wang, Z. Xie, Q. Wu, X. Bai, M. S. Hamdy and H. Chen, Status and perspectives of key materials for PEM electrolyzer, Nano Research Energy, 1, e9120032, 2022.
[8] C. De Grotthuss, Mémoire sur la décomposition de l'eau: et des corps qu'elle tient en dissolution à l'aide de l'électricité galvanique, 1805.
[9] K. D. Kreuer, A. Rabenau and W. Weppner, Vehicle mechanism, a new model for the interpretation of the conductivity of fast proton conductors, Angewandte Chemie International Edition, 21, 208–209, 1982.
[10] D. K. Paul, A. Fraser and K. Karan, Towards the understanding of proton conduction mechanism in PEMFC catalyst layer: Conductivity of adsorbed Nafion films, Electrochemistry Communications, 13, 774–777, 2011.
[11] K. i. Otake and H. Kitagawa, Control of proton‐conductive behavior with nanoenvironment within metal–organic materials, Small, 17, 2006189, 2021.
[12] O. Markovitch and N. Agmon, Structure and energetics of the hydronium hydration shells, The Journal of Physical Chemistry A, 111, 2253–2256, 2007.
[13] O. Markovitch, H. Chen, S. Izvekov, F. Paesani, G. A. Voth and N. Agmon, Special pair dance and partner selection: Elementary steps in proton transport in liquid water, The Journal of Physical Chemistry B, 112, 9456–9466, 2008.
[14] Z. Cao, Y. Peng, T. Yan, S. Li, A. Li and G. A. Voth, Mechanism of fast proton transport along one-dimensional water chains confined in carbon nanotubes, Journal of the American Chemical Society, 132, 11395–11397, 2010.
[15] M. L. Brewer, U. W. Schmitt and G. A. Voth, The formation and dynamics of proton wires in channel environments, Biophysical Journal, 80, 1691–1702, 2001.
[16] C. Dellago, M. M. Naor and G. Hummer, Proton transport through water-filled carbon nanotubes, Physical Review Letters, 90, 105902, 2003.
[17] W. H. Ho, S.-C. Li, Y.-C. Wang, T.-E. Chang, Y.-T. Chiang, Y.-P. Li and C.-W. Kung, Proton-Conductive Cerium-Based Metal–Organic Frameworks, ACS Applied Materials & Interfaces, 13, 55358–55366, 2021.
[18] P. Colomban, Proton Conductors: Solids, membranes and gels-materials and devices, Cambridge University Press, Cambridge, United Kingdom, 1992.
[19] Y. Sone, P. Ekdunge and D. Simonsson, Proton conductivity of Nafion 117 as measured by a four‐electrode AC impedance method, Journal of the Electrochemical Society, 143, 1254–1259, 1996.
[20] T. Soboleva, Z. Xie, Z. Shi, E. Tsang, T. Navessin and S. Holdcroft, Investigation of the through-plane impedance technique for evaluation of anisotropy of proton conducting polymer membranes, Journal of Electroanalytical Chemistry, 622, 145–152, 2008.
[21] Y. Yamazaki, R. Hernandez-Sanchez and S. M. Haile, High total proton conductivity in large-grained yttrium-doped barium zirconate, Chemistry of Materials, 21, 2755–2762, 2009.
[22] L. Sun, S. S. Park, D. Sheberla and M. Dincă, Measuring and reporting electrical conductivity in metal–organic frameworks: Cd2(TTFTB) as a case study, Journal of the American Chemical Society, 138, 14772–14782, 2016.
[23] Z. Meng, A. Aykanat and K. A. Mirica, Proton conduction in 2D aza-fused covalent organic frameworks, Chemistry of Materials, 31, 819–825, 2018.
[24] M. R. Karim, K. Hatakeyama, T. Matsui, H. Takehira, T. Taniguchi, M. Koinuma, Y. Matsumoto, T. Akutagawa, T. Nakamura and S.-i. Noro, Graphene oxide nanosheet with high proton conductivity, Journal of the American Chemical Society, 135, 8097–8100, 2013.
[25] Y. Zheng, Y. Liu, H. Li, Z. Yang, W. Wu, J. Zhang, J. Wu and J. Wang, Carboxyl‐Driven Water Networks on 2D Metal Organic Frameworks for Enhanced Proton Conduction in PEMFCs, Advanced Functional Materials, 35, 2500151, 2025.
[26] S. Mikhailenko, M. Guiver and S. Kaliaguine, Measurements of PEM conductivity by impedance spectroscopy, Solid State Ionics, 179, 619–624, 2008.
[27] K. Ariyoshi, Z. Siroma, A. Mineshige, M. Takeno, T. Fukutsuka, T. Abe and S. Uchida, Electrochemical impedance spectroscopy part 1: fundamentals, Electrochemistry, 90, 102007–102007, 2022.
[28] A. J. Bard, L. R. Faulkner and H. S. White, Electrochemical methods: fundamentals and applications, John Wiley & Sons, Hoboken, New Jersey, United States, 2022.
[29] A. C. Lazanas and M. I. Prodromidis, Electrochemical impedance spectroscopy─a tutorial, ACS Measurement Science Au, 3, 162–193, 2023.
[30] G. He, J. Zhao, S. Hu, L. Li, Z. Li, Y. Li, Z. Li, H. Wu, X. Yang and Z. Jiang, Functionalized carbon nanotube via distillation precipitation polymerization and its application in Nafion-based composite membranes, ACS Applied Materials & Interfaces, 6, 15291–15301, 2014.
[31] P. Ramaswamy, N. E. Wong and G. K. Shimizu, MOFs as proton conductors–challenges and opportunities, Chemical Society Reviews, 43, 5913–5932, 2014.
[32] K. A. Mauritz and R. B. Moore, State of understanding of Nafion, Chemical Reviews, 104, 4535–4586, 2004.
[33] H. Furukawa, K. E. Cordova, M. O’Keeffe and O. M. Yaghi, The chemistry and applications of metal-organic frameworks, Science, 341, 1230444, 2013.
[34] O. M. Yaghi, G. Li and H. Li, Selective binding and removal of guests in a microporous metal–organic framework, Nature, 378, 703–706, 1995.
[35] O. M. Yaghi and H. Li, Hydrothermal synthesis of a metal-organic framework containing large rectangular channels, Journal of the American Chemical Society, 117, 10401–10402, 1995.
[36] M. Kondo, T. Yoshitomi, H. Matsuzaka, S. Kitagawa and K. Seki, Three‐Dimensional Framework with Channeling Cavities for Small Molecules:{[M2(4,4′‐bpy)3(NO3)4]·xH2O}n (M = Co, Ni, Zn), Angewandte Chemie International Edition, 36, 1725–1727, 1997.
[37] S. Kitagawa, R. Kitaura and S. i. Noro, Functional porous coordination polymers, Angewandte Chemie International Edition, 43, 2334–2375, 2004.
[38] O. M. Yaghi, M. O'Keeffe, N. W. Ockwig, H. K. Chae, M. Eddaoudi and J. Kim, Reticular synthesis and the design of new materials, Nature, 423, 705–714, 2003.
[39] M. Eddaoudi, D. B. Moler, H. Li, B. Chen, T. M. Reineke, M. O'keeffe and O. M. Yaghi, Modular chemistry: secondary building units as a basis for the design of highly porous and robust metal−organic carboxylate frameworks, Accounts of Chemical Research, 34, 319–330, 2001.
[40] A. J. Howarth, Y. Liu, P. Li, Z. Li, T. C. Wang, J. T. Hupp and O. K. Farha, Chemical, thermal and mechanical stabilities of metal–organic frameworks, Nature Reviews Materials, 1, 1–15, 2016.
[41] J. K. Schnobrich, K. Koh, K. N. Sura and A. J. Matzger, A framework for predicting surface areas in microporous coordination polymers, Langmuir, 26, 5808–5814, 2010.
[42] J. D. Wuest, Atoms and the void: modular construction of ordered porous solids, Nature Communications, 11, 4652, 2020.
[43] M. Sabo, A. Henschel, H. Fröde, E. Klemm and S. Kaskel, Solution infiltration of palladium into MOF-5: synthesis, physisorption and catalytic properties, Journal of Materials Chemistry, 17, 3827–3832, 2007.
[44] Y.-C. Chen, W.-H. Chiang, D. Kurniawan, P.-C. Yeh, K.-i. Otake and C.-W. Kung, Impregnation of graphene quantum dots into a metal–organic framework to render increased electrical conductivity and activity for electrochemical sensing, ACS Applied Materials & Interfaces, 11, 35319–35326, 2019.
[45] P. Deria, J. E. Mondloch, E. Tylianakis, P. Ghosh, W. Bury, R. Q. Snurr, J. T. Hupp and O. K. Farha, Perfluoroalkane functionalization of NU-1000 via solvent-assisted ligand incorporation: synthesis and CO2 adsorption studies, Journal of the American Chemical Society, 135, 16801–16804, 2013.
[46] H. Noh, Y. Cui, A. W. Peters, D. R. Pahls, M. A. Ortuño, N. A. Vermeulen, C. J. Cramer, L. Gagliardi, J. T. Hupp and O. K. Farha, An exceptionally stable metal–organic framework supported molybdenum(VI) oxide catalyst for cyclohexene epoxidation, Journal of the American Chemical Society, 138, 14720–14726, 2016.
[47] L. J. Murray, M. Dincă and J. R. Long, Hydrogen storage in metal–organic frameworks, Chemical Society Reviews, 38, 1294–1314, 2009.
[48] I. Senkovska, V. Bon, A. Mosberger, Y. Wang and S. Kaskel, Adsorption and separation by flexible MOFs, Advanced Materials, 37, 2414724, 2025.
[49] J.-R. Li, J. Sculley and H.-C. Zhou, Metal–organic frameworks for separations, Chemical Reviews, 112, 869–932, 2012.
[50] T. Chen and D. Zhao, Post-synthetic modification of metal-organic framework-based membranes for enhanced molecular separations, Coordination Chemistry Reviews, 491, 215259, 2023.
[51] Y. Liu, A. J. Howarth, J. T. Hupp and O. K. Farha, Selective photooxidation of a mustard‐gas simulant catalyzed by a porphyrinic metal–organic framework, Angewandte Chemie International Edition, 127, 9129–9133, 2015.
[52] Q. Wang and D. Astruc, State of the art and prospects in metal–organic framework (MOF)-based and MOF-derived nanocatalysis, Chemical Reviews, 120, 1438–1511, 2019.
[53] P. Horcajada, T. Chalati, C. Serre, B. Gillet, C. Sebrie, T. Baati, J. F. Eubank, D. Heurtaux, P. Clayette and C. Kreuz, Porous metal–organic-framework nanoscale carriers as a potential platform for drug delivery and imaging, Nature Materials, 9, 172–178, 2010.
[54] M. X. Wu and Y. W. Yang, Metal–organic framework (MOF)‐based drug/cargo delivery and cancer therapy, Advanced Materials, 29, 1606134, 2017.
[55] L. E. Kreno, K. Leong, O. K. Farha, M. Allendorf, R. P. Van Duyne and J. T. Hupp, Metal–organic framework materials as chemical sensors, Chemical Reviews, 112, 1105–1125, 2012.
[56] M. Ko, L. Mendecki, A. M. Eagleton, C. G. Durbin, R. M. Stolz, Z. Meng and K. A. Mirica, Employing conductive metal–organic frameworks for voltammetric detection of neurochemicals, Journal of the American Chemical Society, 142, 11717–11733, 2020.
[57] D. Sheberla, J. C. Bachman, J. S. Elias, C.-J. Sun, Y. Shao-Horn and M. Dincă, Conductive MOF electrodes for stable supercapacitors with high areal capacitance, Nature Materials, 16, 220–224, 2017.
[58] G. Lee, G. Park and S. S. Park, Molecular-level pore tuning in 2D conductive metal–organic frameworks for advanced supercapacitor performance, Journal of the American Chemical Society, 146, 29767–29772, 2024.
[59] Y. Ye, L. Gong, S. Xiang, Z. Zhang and B. Chen, Metal–organic frameworks as a versatile platform for proton conductors, Advanced Materials, 32, 1907090, 2020.
[60] D.-W. Lim and H. Kitagawa, Proton transport in metal–organic frameworks, Chemical Reviews, 120, 8416–8467, 2020.
[61] D. Castelvecchi and M. Naddaf, Chemistry Nobel awarded for ‘super sponge’ materials, Nature, 646, 16, 2025.
[62] N. C. Burtch, H. Jasuja and K. S. Walton, Water stability and adsorption in metal–organic frameworks, Chemical Reviews, 114, 10575–10612, 2014.
[63] M. Ding, X. Cai and H.-L. Jiang, Improving MOF stability: approaches and applications, Chemical Science, 10, 10209–10230, 2019.
[64] S. Yuan, L. Feng, K. Wang, J. Pang, M. Bosch, C. Lollar, Y. Sun, J. Qin, X. Yang and P. Zhang, Stable metal–organic frameworks: design, synthesis, and applications, Advanced Materials, 30, 1704303, 2018.
[65] W. Zheng and L. Y. S. Lee, Metal–organic frameworks for electrocatalysis: catalyst or precatalyst?, ACS Energy Letters, 6, 2838–2843, 2021.
[66] S. Yuan, J.-S. Qin, C. T. Lollar and H.-C. Zhou, Stable metal–organic frameworks with group 4 metals: current status and trends, ACS Central Science, 4, 440–450, 2018.
[67] S. Roy, Z. Huang, A. Bhunia, A. Castner, A. K. Gupta, X. Zou and S. Ott, Electrocatalytic hydrogen evolution from a cobaloxime-based metal–organic framework thin film, Journal of the American Chemical Society, 141, 15942–15950, 2019.
[68] K.-X. Zhao, G.-Q. Zhang, X.-R. Wu, H.-B. Luo, Z.-X. Han, Y. Liu and X.-M. Ren, Proton conduction in zirconium-based metal–organic frameworks for advanced applications, ACS Applied Electronic Materials, 7, 3164–3175, 2025.
[69] L. Zhu, H. Yang, T. Xu, F. Shen and C. Si, Precision-engineered construction of proton-conducting metal–organic frameworks, Nano-Micro Letters, 17, 87, 2025.
[70] J. M. Taylor, R. K. Mah, I. L. Moudrakovski, C. I. Ratcliffe, R. Vaidhyanathan and G. K. Shimizu, Facile proton conduction via ordered water molecules in a phosphonate metal−organic framework, Journal of the American Chemical Society, 132, 14055–14057, 2010.
[71] X. Chen and G. Li, Proton conductive Zr-based MOFs, Inorganic Chemistry Frontiers, 7, 3765–3784, 2020.
[72] H.-B. Luo, Q. Ren, P. Wang, J. Zhang, L. Wang and X.-M. Ren, High proton conductivity achieved by encapsulation of imidazole molecules into proton-conducting MOF-808, ACS Applied Materials & Interfaces, 11, 9164–9171, 2019.
[73] F. Yang, H. Huang, X. Wang, F. Li, Y. Gong, C. Zhong and J.-R. Li, Proton conductivities in functionalized UiO-66: tuned properties, thermogravimetry mass, and molecular simulation analyses, Crystal Growth & Design, 15, 5827–5833, 2015.
[74] P. M. Unnikrishnan, G. Premanand and S. K. Das, Fabricating MOF–GO composites by modulating graphene oxide content to achieve superprotonic conductivity, Inorganic Chemistry, 64, 3506–3517, 2025.
[75] L. Yang, B. Tang and P. Wu, Metal–organic framework–graphene oxide composites: a facile method to highly improve the proton conductivity of PEMs operated under low humidity, Journal of Materials Chemistry A, 3, 15838–15842, 2015.
[76] Z. Rao, K. Feng, B. Tang and P. Wu, Construction of well interconnected metal-organic framework structure for effectively promoting proton conductivity of proton exchange membrane, Journal of Membrane Science, 533, 160–170, 2017.
[77] M. K. Sarango‐Ramírez, M. Donoshita, Y. Yoshida, D. W. Lim and H. Kitagawa, Cooperative Proton and Li‐ion Conduction in a 2D‐Layered MOF via Mechanical Insertion of Lithium Halides, Angewandte Chemie International Edition, 62, e202301284, 2023.
[78] A. Pathak and B. Manna, Two‐Dimensional Metal–Organic Frameworks for Proton Conduction, Sensing, and Separation, ChemNanoMat, 12, e202500339, 2026.
[79] R. Wang, Z. Wang, Y. Xu, F. Dai, L. Zhang and D. Sun, Porous Zirconium Metal–Organic Framework Constructed from 2D → 3D Interpenetration Based on a 3,6-Connected kgd Net, Inorganic Chemistry, 53, 7086–7088, 2014.
[80] J. Ma, A. G. Wong-Foy and A. J. Matzger, The role of modulators in controlling layer spacings in a tritopic linker based zirconium 2D microporous coordination polymer, Inorganic Chemistry, 54, 4591–4593, 2015.
[81] Y. Wang, L. Feng, J. Pang, J. Li, N. Huang, G. S. Day, L. Cheng, H. F. Drake, Y. Wang and C. Lollar, Photosensitizer‐anchored 2D MOF nanosheets as highly stable and accessible catalysts toward artemisinin production, Advanced Science, 6, 1802059, 2019.
[82] Y.-L. Chen, C.-H. Shen, C.-W. Huang and C.-W. Kung, Terbium-modified two-dimensional zirconium-based metal–organic frameworks for photoluminescence detection of nitrite, Molecular Systems Design & Engineering, 8, 330–340, 2023.
[83] M. Szufla, A. Choroś, W. Nitek and D. Matoga, A porous sulfonated 2D zirconium metal–organic framework as a robust platform for proton conduction, Chemistry–A European Journal, 28, e202200835, 2022.
[84] T.-C. Lin, K.-C. Wu, J.-W. Chang, Y.-L. Chen, M.-D. Tsai and C.-W. Kung, Immobilization of europium and terbium ions with tunable ratios on a dispersible two-dimensional metal–organic framework for ratiometric photoluminescence detection of D2O, Dalton Transactions, 53, 11426–11435, 2024.
[85] L. Feng, Y. Qiu, Q.-H. Guo, Z. Chen, J. S. Seale, K. He, H. Wu, Y. Feng, O. K. Farha and R. D. Astumian, Active mechanisorption driven by pumping cassettes, Science, 374, 1215–1221, 2021.
[86] Z. Lu, J. Liu, X. Zhang, Y. Liao, R. Wang, K. Zhang, J. Lyu, O. K. Farha and J. T. Hupp, Node-Accessible Zirconium MOFs, Journal of the American Chemical Society, 142, 21110–21121, 2020.
[87] K.-C. Wu, M.-D. Tsai, C.-H. Wu, T.-H. Yang, Y.-L. Chen and C.-W. Kung, Redox-active cerium-based metal–organic layers coordinated on carbon nanotubes as materials for supercapacitors, APL Materials, 12, 2024.
[88] S. Goswami, D. Ray, K.-i. Otake, C.-W. Kung, S. J. Garibay, T. Islamoglu, A. Atilgan, Y. Cui, C. J. Cramer and O. K. Farha, A porous, electrically conductive hexa-zirconium(IV) metal–organic framework, Chemical Science, 9, 4477–4482, 2018.
[89] C.-W. Kung, K. Otake, C. T. Buru, S. Goswami, Y. Cui, J. T. Hupp, A. M. Spokoyny and O. K. Farha, Increased Electrical Conductivity in a Mesoporous Metal–Organic Framework Featuring Metallacarboranes Guests, Journal of the American Chemical Society, 140, 3871–3875, 2018.
[90] R. G. Linford and S. Hackwood, Physical techniques for the study of solid electrolytes, Chemical Reviews, 81, 327–364, 1981.
[91] P. Colomban and A. Novak, Proton transfer and superionic conductivity in solids and gels, Journal of Molecular Structure, 177, 277–308, 1988.
[92] L. Greenspan, Journal of Research of the National Bureau of Standards. Section A, Physics and chemistryHumidity fixed points of binary saturated aqueous solutions, Journal of Research of the National Bureau of Standards. Section A, Physics and Chemistry, 81, 89, 1977.
[93] C.-H. Shen, Y. Zhao, H. N. Nam, L. Zhu, Q. M. Phung, V. Austen, M. Kim, D. Jiang, X. Wei and T. Yokoshima, Unlocking coordination sites of metal–organic frameworks for high-density and accessible copper nanoparticles toward electrochemical nitrate reduction to ammonia, Chemical Science, 16, 7026–7038, 2025.
[94] L. Stobinski, B. Lesiak, A. Malolepszy, M. Mazurkiewicz, B. Mierzwa, J. Zemek, P. Jiricek and I. Bieloshapka, Graphene oxide and reduced graphene oxide studied by the XRD, TEM and electron spectroscopy methods, Journal of Electron Spectroscopy and Related Phenomena, 195, 145–154, 2014.
[95] A. Sharma, J. Lim, S. Jeong, S. Won, J. Seong, S. Lee, Y. S. Kim, S. B. Baek and M. S. Lah, Superprotonic conductivity of MOF‐808 achieved by controlling the binding mode of grafted sulfamate, Angewandte Chemie International Edition, 133, 14455–14459, 2021.
[96] Y. Li and R. T. Yang, Gas adsorption and storage in metal−organic framework MOF-177, Langmuir, 23, 12937–12944, 2007.
[97] J.-W. Chang, T.-C. Lin, Y.-L. Chen, P.-C. Han, S.-C. Yang, M.-D. Tsai, K. C.-W. Wu and C.-W. Kung, Dual modifications of sensitizers and lanthanide ions on a two-dimensional zirconium-based metal–organic framework for photoluminescent detection, CrystEngComm, 26, 2852–2861, 2024.
[98] S. Thakur and N. Karak, Green reduction of graphene oxide by aqueous phytoextracts, Carbon, 50, 5331–5339, 2012.
[99] G. Srinivas, J. W. Burress, J. Ford and T. Yildirim, Porous graphene oxide frameworks: synthesis and gas sorption properties, Journal of Materials Chemistry, 21, 11323–11329, 2011.
[100] V. Brusko, A. Khannanov, A. Rakhmatullin and A. M. Dimiev, Unraveling the infrared spectrum of graphene oxide, Carbon, 229, 119507, 2024.
[101] R. Al-Gaashani, A. Najjar, Y. Zakaria, S. Mansour and M. Atieh, XPS and structural studies of high quality graphene oxide and reduced graphene oxide prepared by different chemical oxidation methods, Ceramics International, 45, 14439–14448, 2019.
[102] L. Liu, Z. Qiao, X. Cui, C. Pang, H. Liang, P. Xie, X. Luo, Z. Huang, Y. Zhang and Z. Zhao, Amino acid imprinted UiO-66s for highly recognized adsorption of small angiotensin-converting-enzyme-inhibitory peptides, ACS Applied Materials & Interfaces, 11, 23039–23049, 2019.
[103] T. Shen, X. Feng, L. Fan, L. Li, Y. Zhang, B. Chai, U. Khan and X. Wang, Temperature-dependent synthesis of oxygen vacancy-rich NH2–UiO-66: a strategy for sustainable photocatalytic nitrogen fixation, Crystal Growth & Design, 25, 5312–5320, 2025.
[104] J. Liu, Z. Li, X. Zhang, K.-i. Otake, L. Zhang, A. W. Peters, M. J. Young, N. M. Bedford, S. P. Letourneau and D. J. Mandia, Introducing nonstructural ligands to zirconia-like metal–organic framework nodes to tune the activity of node-supported nickel catalysts for ethylene hydrogenation, ACS Catalysis, 9, 3198–3207, 2019.
[105] A. R. Heiba, M. Abdel-Salam, T. Yoon and E. El Sawy, Zr-MOF composites with zipped and unzipped carbon nanotubes for high-performance electrochemical supercapacitors, Nanoscale, 17, 459–473, 2025.
[106] T. E. DeCoursey and V. V. Cherny, Deuterium isotope effects on permeation and gating of proton channels in rat alveolar epithelium, Journal of General Physiology, 109, 415–434, 1997.
[107] D. W. Kang, K. S. Lim, K. J. Lee, J. H. Lee, W. R. Lee, J. H. Song, K. H. Yeom, J. Y. Kim and C. S. Hong, Cost‐Effective, High‐Performance Porous‐Organic‐Polymer Conductors Functionalized with Sulfonic Acid Groups by Direct Postsynthetic Substitution, Angewandte Chemie International Edition, 128, 16357–16360, 2016.
[108] F. Yang, G. Xu, Y. Dou, B. Wang, H. Zhang, H. Wu, W. Zhou, J.-R. Li and B. Chen, A flexible metal–organic framework with a high density of sulfonic acid sites for proton conduction, Nature Energy, 2, 877–883, 2017.