Protective Fabrics: Metal-Organic Framework Textiles for Rapid Photocatalytic Sulfur Mustard Simulant Detoxification

Abstract

•Rapid photocatalytic detoxification of vesicant simulant using Al-PMOF/fiber•Conformal and robust Al-PMOF film integration into polymer textiles•Lower-temperature synthesis of Al-PMOF photocatalyst using cosolvent strategy•Mechanism study on Al-PMOF formation driven by Al2O3 thin film Several unfortunate events in the recent news highlight the problem of violent and injurious use of deadly chemical warfare agents by terrorists and villainous states, raising the need for new materials to protect soldiers, first responders, and the public. This work reports for the first time that Al-PMOF (Al-porphyrin-based metal-organic framework) performs as a superior and rapid visible-light photocatalyst for detoxifying 2-chloroethyl ethyl sulfide, a mustard gas vesicant simulant. Also for the first time, active Al-PMOF is formed as a uniform and robust film on the surface of polymer fabrics, providing a pathway for scalable production of protective clothing, masks, and other gear. The multifunctional MOF-fiber textiles achieved in this study show great potential as field-deployable protective gear against toxic chemicals. Metal-organic frameworks (MOFs) can catalyze toxic chemical decontamination, but new MOF materials and synthesis strategies are needed to improve performance, particularly in field-usable MOF-textile formats. This article reports for the first time the exceptional photocatalytic reactivity of Al-PMOF (Al-porphyrin-based MOF), composed of an earth-abundant metal-containing Al(OH)O4 cluster bridged by H2TCPP (5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) chromophores, against the toxic sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) under visible-light irradiation. Furthermore, Al-PMOF is strongly immobilized into polymeric fibers via well-controlled Al2O3 solid film conversion using dimethylformamide/water cosolvent. The approach enables a secure integration of conformal Al-PMOF films onto polymer fibers at a relatively low synthesis temperature (120°C). In addition, on a per-unit mass of MOF basis, the surface-bound Al-PMOF films enable extremely rapid CEES detoxification turnover frequency, up to 170 molCEESmolchromophore−1min−1, more than 10-fold faster than the best MOF powders and 2-fold better than MOF films reported to date. Metal-organic frameworks (MOFs) can catalyze toxic chemical decontamination, but new MOF materials and synthesis strategies are needed to improve performance, particularly in field-usable MOF-textile formats. This article reports for the first time the exceptional photocatalytic reactivity of Al-PMOF (Al-porphyrin-based MOF), composed of an earth-abundant metal-containing Al(OH)O4 cluster bridged by H2TCPP (5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) chromophores, against the toxic sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) under visible-light irradiation. Furthermore, Al-PMOF is strongly immobilized into polymeric fibers via well-controlled Al2O3 solid film conversion using dimethylformamide/water cosolvent. The approach enables a secure integration of conformal Al-PMOF films onto polymer fibers at a relatively low synthesis temperature (120°C). In addition, on a per-unit mass of MOF basis, the surface-bound Al-PMOF films enable extremely rapid CEES detoxification turnover frequency, up to 170 molCEESmolchromophore−1min−1, more than 10-fold faster than the best MOF powders and 2-fold better than MOF films reported to date. 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A water-stable porphyrin-based metal-organic framework active for visible-light photocatalysis.Angew. Chem. Int. Ed. 2012; 51: 7440-7444Crossref PubMed Scopus (602) Google Scholar is built with aluminum, the most abundant metallic element in the Earth's crust, arranged into infinite trans-connected Al(OH)O4 polyhedra secondary building units (SBUs) connected along the b axis, linked by H2TCPP (5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) photosensitizer.24Lee C.Y. Farha O.K. Hong B.J. Sarjeant A.A. Nguyen S.T. Hupp J.T. Light-harvesting metal-organic frameworks (MOFs): efficient strut-to-strut energy transfer in bodipy and porphyrin-based MOFs.J. Am. Chem. Soc. 2011; 133: 15858-15861Crossref PubMed Scopus (643) Google Scholar Until now, MOF-functionalized textiles capable of selective and rapid partial oxidation of HD simulants have not been realized or reported. Using a new low-temperature mixed-solvent synthesis, Al-PMOF is formed as a conformal and dense layer on the surface of flexible textile fibers, demonstrating feasible routes to advanced protective clothing and other equipment. Successful integration of Al-PMOF into polypropylene (PP) fiber ([email protected]) leverages a metal oxide coordination replication approach, whereby Al2O3 thin films formed by atomic layer deposition (ALD) are converted to MOF films via synthesis assisted by a cosolvent (dimethylformamide [DMF] and water). The amorphous ALD Al2O3 film conformally deposited on PP provides a strong adhesive layer between fiber substrate and the MOF film. This is in contrast to conventional methods, which generally result in poor crystallization and adhesion of the MOF crystals to substrates. The MOF/fiber composites are versatile not only in fast neutralization of CEES but also in colorimetric pH sensing and selective organic contaminant removal. Hydrothermal synthesis of Al-PMOF powder was previously reported using AlCl3·6H2O and H2TCPP in water at 180°C.23Fateeva A. Chater P.A. Ireland C.P. Tahir A.A. Khimyak Y.Z. Wiper P.V. Darwent J.R. Rosseinsky M.J. A water-stable porphyrin-based metal-organic framework active for visible-light photocatalysis.Angew. Chem. Int. Ed. 2012; 51: 7440-7444Crossref PubMed Scopus (602) Google Scholar This required temperature is generally higher than the point where many polymeric fiber materials begin to degrade (e.g., 125°C for PP and 150°C for cotton).25Hyde G.K. Scarel G. Spagnola J.C. Peng Q. Lee K. Gong B. Roberts K.G. Roth K.M. Hanson C.A. Devine C.K. et al.Atomic layer deposition and abrupt wetting transitions on nonwoven polypropylene and woven cotton fabrics.Langmuir. 2010; 26: 2550-2558Crossref PubMed Scopus (139) Google Scholar Porphyrin MOFs are known to crystallize at moderate temperatures using DMF/water mixtures to solvate the hydrophobic linkers.26Zhao Y. Kornienko N. Liu Z. Zhu C. Asahina S. Kuo T.R. Bao W. Xie C. Hexemer A. Terasaki O. et al.Mesoscopic constructs of ordered and oriented metal-organic frameworks on plasmonic silver nanocrystals.J. Am. Chem. Soc. 2015; 137: 2199-2202Crossref PubMed Scopus (123) Google Scholar Therefore, to realize low-temperature Al-PMOF synthesis, a range of DMF/water solvent ratios were explored, combined with various sources of Al, including AlCl3·6H2O, commercial Al2O3 powder, and ALD Al2O3 thin films produced in our laboratory (Supplemental Experimental Procedures). Reactions between AlCl3·6H2O and H2TCPP precursors at 120°C in various solvent systems (pure DMF, DMF/water ratio [D/W] = 3:1 [v/v], D/W = 1:1, D/W = 1:3, or pure water) produced powders with a range of properties. Using pure water, the powders show undefined crystallinity by X-ray diffraction (XRD), and non-porous structure by N2 isotherms at 77 K (Figures 1B and 1C). Results in pure DMF, D/W = 3:1, or D/W = 1:1 also showed limited success (Figure S1). However, using D/W = 1:3 yielded crystalline patterns and UV-visible spectra27Sadeghi N. Sharifnia S. Do T.-O. Enhanced CO2 photoreduction by a graphene-porphyrin metal-organic framework under visible light irradiation.J. Mater. Chem. A. 2018; 6: 18031-18035Crossref Google Scholar (Figure S2) identical with Al-PMOF made at 180°C in pure water, and the Brunauer-Emmett-Teller (BET) surface area of 1,728 ± 250 m2/g was comparable with the previously reported range of 1,200–1,400 m2/g for this MOF prepared at 180°C.23Fateeva A. Chater P.A. Ireland C.P. Tahir A.A. Khimyak Y.Z. Wiper P.V. Darwent J.R. Rosseinsky M.J. A water-stable porphyrin-based metal-organic framework active for visible-light photocatalysis.Angew. Chem. Int. Ed. 2012; 51: 7440-7444Crossref PubMed Scopus (602) Google Scholar,27Sadeghi N. Sharifnia S. Do T.-O. Enhanced CO2 photoreduction by a graphene-porphyrin metal-organic framework under visible light irradiation.J. Mater. Chem. 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Chem. 2015; 87: 1051-1069Crossref Scopus (9149) Google Scholar Figure 1E shows scanning electron microscopy (SEM) images of powders formed at 120°C using AlCl3·6H2O and various DMF/water ratios. Consistent with XRD, all ratios with DMF display Al-PMOF crystals, while the synthesis with pure water results in only assembled H2TCPP salts (Figure S2). Low-temperature Al-PMOF synthesis was also achieved to a lesser extent under some conditions using solid Al2O3 in place of the AlCl3·6H2O salt. Using the favorable D/W = 1:3 synthesis at 120°C with commercial Al2O3 powder yielded only a partial reaction and non-porous solids with complex crystallinity (Figures S3 and S4; Supplemental Experimental Procedures). In contrast to solid powders, using ALD Al2O3 thin films formed at 90°C as an aluminum source showed significantly improved results. Al2O3 formed by low-temperature ALD is known to be less dense than higher-temperature pyrolyzed Al2O3 powders or films,31Groner M.D. Fabreguette F.H. Elam J.W. George S.M. Low-temperature Al2O3 atomic layer deposition.Chem. Mater. 2004; 16: 639-645Crossref Scopus (1168) Google Scholar consistent with it being more reactive than commercial Al2O3 powder. The innate uniformity and conformality of ALD thin films also make them suitable as source materials for MOF thin films on planar and non-planar surfaces. Figure 1F shows SEM results of thin film Al-PMOFs produced from ∼30 nm of ALD Al2O3 on a native-oxide-coated planar Si wafer using various DMF/water ratios. Consistent with results using AlCl3·6H2O, the D/W = 1:3 cosolvent system rendered the densest packing of surface-bound 2D nanometer-thick Al-PMOF film with remarkably large (micron-sized) lateral dimension. Using AlCl3·6H2O under similar conditions yielded crystals limited to ∼500 nm (Figure 1E). The successful synthesis of Al-PMOF from ALD Al2O3 enabled a direct pathway for Al-PMOF-textile formation, as outlined in Figure 2A. After PP fibers are coated with a conformal ALD Al2O3 film (∼30 nm),32Zhao J. Losego M.D. Lemaire P.C. Williams P.S. Gong B. Atanasov S.E. Blevins T.M. Oldham C.J. Walls H.J. Shepherd S.D. et al.Highly adsorptive, MOF-functionalized nonwoven fiber mats for hazardous gas capture enabled by atomic layer deposition.Adv. Mater. Interfaces. 2014; 1: 1400040Crossref Scopus (97) Google Scholar,[33]Lee DT Zhao J Oldham CJ Peterson GW Parsons GN UiO-66-NH2 metal-organic framework (MOF) nucleation on TiO2, ZnO, and Al2O3 atomic layer deposition-treated polymer fibers: role of metal oxide on MOF growth and catalytic hydrolysis of chemical warfare agent simulants.ACS Appl. Mater. Interfaces. 2017; 9: 44847-44855Crossref PubMed Scopus (130) Google Scholar the Al2O3 is allowed to react with H2TCPP linkers dissolved in solvent yielding Al-PMOF/fibers, as shown in Figure 2B, with best results obtained using the D/W = 1:3 cosolvent system. After the reaction was completed, the remaining reaction solution was passed through a filtration membrane and no Al-PMOF powder was observed, indicating that MOF formation occurred only on the fiber surface, and crystals did not dislodge from the fiber surface after growth. Results of analysis of Al-PMOF textiles and their Si wafer-bound counterparts are given in Figure 3. XRD peaks (Figure 3A) for Al-PMOF textiles formed at 120°C with D/W = 1:3 agree well with our Al-PMOF powders and its simulated pattern. BET surface area calculated from N2 isotherms (Figure 3B) further confirmed that the D/W = 1:3 solvent system promotes microporous Al-PMOF on fibers with a high surface area of 233 m2/g(MOF+fiber). Fourier transform infrared (FTIR) studies also verify characteristic vibrational modes of the coordination—vasym[C=O] (1,612 cm−1) and vsym[C=O] (1,442 cm−1)—between Al(OH)O4 clusters and the carboxyl groups of H2TCPP (Figures 3C and S5),27Sadeghi N. Sharifnia S. Do T.-O. Enhanced CO2 photoreduction by a graphene-porphyrin metal-organic framework under visible light irradiation.J. Mater. Chem. A. 2018; 6: 18031-18035Crossref Google Scholar as well as other modes expected in Al-PMOF (detailed characteristic vibrational modes are described in Supplemental Experimental Procedures). X-ray photoelectron spectroscopy (XPS) analyses (Figures 3D–3F) of Al-PMOF film made with D/W = 1:3 cosolvent on Si/SiO2 are also consistent with Al-PMOF,27Sadeghi N. Sharifnia S. Do T.-O. Enhanced CO2 photoreduction by a graphene-porphyrin metal-organic framework under visible light irradiation.J. Mater. Chem. A. 2018; 6: 18031-18035Crossref Google Scholar and analogous to those from MIL-53(Al).[33]Lee DT Zhao J Oldham CJ Peterson GW Parsons GN UiO-66-NH2 metal-organic framework (MOF) nucleation on TiO2, ZnO, and Al2O3 atomic layer deposition-treated polymer fibers: role of metal oxide on MOF growth and catalytic hydrolysis of chemical warfare agent simulants.ACS Appl. Mater. Interfaces. 2017; 9: 44847-44855Crossref PubMed Scopus (130) Google Scholar The high-resolution O 1s peak at 532.4 eV and Al 2p peak at 74.8 eV correspond to the coordination of the Al cations with the oxygen anions of the H2TCPP linker. Smaller peaks at 534 eV in O 1s and 76.2 eV in Al 2p are also observed, which is attributed to the presence of dangling carboxylic groups, by-products of Al-O/-OH, or defective sites in MOFs produced during the synthesis. MOF-formation energetics and kinetics are known to be adjustable by selection of solvent composition.34Ameloot R. Gobechiya E. Uji-i H. Martens J.A. Hofkens J. Alaerts L. Sels B.F. De Vos D.E. Direct patterning of oriented metal-organic framework crystals via control over crystallization kinetics in clear precursor solutions.Adv. Mater. 2010; 22: 2685-2688Crossref PubMed Scopus (198) Google Scholar In this case, however, the favorable results obtained with the ALD Al2O3 and D/W = 1:3 are understood by a balance between a solid surface reaction and favorable solvation control. Specifically, as confirmed by thermodynamic calculation35Roine A. Outotec HSC Chemistry Software. Outotec, 2018www.outotec.com/HSCGoogle Scholar (Supplemental Experimental Procedures), hydrophilic alumina undergoes favorable hydrolysis in water36Correa G.C. Bao B. Strandwitz N.C. Chemical stability of titania and alumina thin films formed by atomic layer deposition.ACS Appl. Mater. Interfaces. 2015; 7: 14816-14821Crossref PubMed Scopus (78) Google Scholar but is robustly resistant to DMF.29Moran C.M. Joshi J.N. Marti R.M. Hayes S.E. Walton K.S. Structured growth of metal-organic framework MIL-53(Al) from solid aluminum carbide precursor.J. Am. Chem. Soc. 2018; 140: 9148-9153Crossref PubMed Scopus (32) Google Scholar In contrast, the hydrophobic H2TCPP linker readily solvates in DMF but only weakly in water.37Persson I. Solvation and complex formation in strongly solvating solvents.Pure Appl. Chem. 1986; 58: 1153-1161Crossref Scopus (146) Google Scholar Figures 4A and 4B illustrate a proposed mechanism for the Al-PMOF formation driven by ALD Al2O3 film and H2TCPP in the D/W cosolvent. The rapid hydrolysis of the ALD Al2O3 surface yields surface-connected Al(OH)x<3 (Supplemental Experimental Procedures) as well as release of water-solvated Al3+ ions into the near-surface region.38Reboul J. Furukawa S. Horike N. Tsotsalas M. Hirai K. Uehara H. Kondo M. Louvain M. Sakata O. Kitagawa S. Mesoscopic architectures of porous coordination polymers fabricated by pseudomorphic replication.Nat. Mater. 2012; 11: 717Crossref PubMed Scopus (301) Google Scholar,39Robatjazi H. Weinberg D. Swearer D.F. Jacobson C. Zhang M. Tian S. Zhou L. Nordlander P. Halas N.J. Metal-organic frameworks tailor the properties of aluminum nanocrystals.Sci. Adv. 2019; 5: eaav5340Crossref PubMed Scopus (52) Google Scholar The hydroxylated oxide and solvated ions allow facile assembly of the SBUs.40Li Z. Wu Y. Li J. Zhang Y. Zou X. Li F. The metal-organic framework MIL-53(Al) constructed from multiple metal sources: alumina, aluminum hydroxide, and boehmite.Chem. A Eur. J. 2015; 21: 6913-6920Crossref PubMed Scopus (58) Google Scholar Likewise, the balanced solvent ratio allows the solvated H2TCPP to access and bind to surface coordination sites, promoting MOF lattice formation at low reaction temperature (i.e., 120°C) (Figures S6 and S7). Altering the DMF/water ratio impedes the desired reactions. Excess DMF produces insufficient surface hydrolysis and favors the strong resistance between DMF and hydroxide, thereby slowing MOF formation kinetics. Excess water depletes the H2TCPP concentration at the growth surface, and promotes Al3+ dissolution and homogeneous MOF nucleation in liquid phase. The proposed reaction mechanism is further supported by a cross-sectional analysis of the Al-PMOF film on silicon obtained by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM, Figures 4C and 4D). Starting from a seamless 30-nm Al2O3 ALD layer, the cross-section elemental distribution by high-resolution energy-dispersive X-ray analysis (EDX) mapping confirms a porous and swollen (∼40 nm) interface layer between Al-PMOF and the Si substrate,36Correa G.C. Bao B. Strandwitz N.C. Chemical stability of titania and alumina thin films formed by atomic layer deposition.ACS Appl. Mater. Interfaces. 2015; 7: 14816-14821Crossref PubMed Scopus (78) Google Scholar composed of porous hydrated alumina (i.e., AlO(OH) and Al(OH)x<3). As a control experiment, we also performed a heterogeneous Al-PMOF growth on ALD TiO2 surface coated on silicon wafer (Si/SiO2@TiO2) using AlCl3·6H2O and H2TCPP with solvent mixture (D/W = 1:3) at 120°C. Thermodynamic analysis35Roine A. Outotec HSC Chemistry Software. Outotec, 2018www.outotec.com/HSCGoogle Scholar shows that hydrolysis of TiO2 is energetically less favorable than for Al2O3. We find that even with AlCl3·6H2O present in solution, the TiO2 produces a sparser coating of Al-PMOF compared with Al2O3 (Figure S8), consistent with the aluminum hydroxide being an important intermediate in Al-PMOF film growth. Photo-oxidation of CWA simulant CEES (Figure 5A) was tested in contact with Al-PMOF powder (1.2 mgMOF, 0.7 mol %) and the Al-PMOF fabric composite catalyst (8.5 mg(MOF+fiber), 0.3 mgMOF, 0.2 mol %) under O2 and LED irradiation (Supplemental Experimental Procedures). In Figure 5B, the half-life for CEES degradation using the Al-PMOF powder and Al-PMOF-fabric was 16 and 4 min, respectively, with negligible degradation using PP or PP with Al2O3 only. Using H2TCPP linker only (1.2 mglinker, 0.8 mol %) produced a half-life of 6 min. Without light, CEES showed no measurable degradation even after 60 min in contact with the MOF-fabric catalyst (Figure S9). Experimental details, MOF mass fraction and catalyst loading calculation, resulting gas chromatography-mass spectrometry (GC-MS) spectra, and kinetic data analysis are given in Supplemental Experimental Procedures and Figures S10–S13. In this report, we calculated MOF mass fraction in Al-PMOF/fiber composites using a BET method, which can provide values for MOF mass loading as reliable as those from an inductively coupled plasma optical emission spectroscopy analysis after digesting the composites.22Zhao J. Lee D.T. Yaga R.W. Hall M.G. Barton H.F. Woodward I.R. Oldham C.J. Walls H.J. Peterson G.W. Parsons G.N. Ultra-fast degradation of chemical warfare agents using MOF-nanofiber kebabs.Angew. Chem. Int. Ed. 2016; 55: 13224-13228Crossref PubMed Scopus (160) Google Scholar As confirmed by GC-MS spectra in Figure 5C, the only product during the oxidation was the significantly less toxic 2-chloroethyl ethyl sulfoxide (CEESO), with no signal related to the toxic CEESO2 and ethyl vinyl sulfone (EVSO2), demonstrating highly selective partial oxidation in our photocatalytic system (Figures S10–S12). The result confirms that Al-PMOF is capable of absorbing the light, generating 1O2, and rapidly oxidizing CEES to CEESO. After complete removal of CEES, however, the amount of CEESO produced is about one-third of the CEES amount initially added. We speculate that some of the products are adsorbed onto or within the composite materials during the reaction, thus leading to a lesser amount of CEESO measured from the GC-MS. Turnover frequencies (TOFs) for CEES oxidation were determined (as described in Supplemental Experimental Procedures) to directly compare our Al-PMOF catalyst with previously reported Zr6-based MOFs, including PCN-222/MOF545,19Liu Y. Howarth A.J. Hupp J.T. Farha O.K. Selective photooxidation of a mustard-gas simulant catalyzed by a porphyrinic metal-organic framework.Angew. Chem. Int. Ed. 2015; 54: 9001-9005Crossref PubMed Scopus (210) Google Scholar,41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google Scholar NU-1000,18Liu Y. Buru C.T. Howarth A.J. Mahle J.J. Buchanan J.H. DeCoste J.B. Hupp J.T. Farha O.K. Efficient and selective oxidation of sulfur mustard using singlet oxygen generated by a pyrene-based metal-organic framework.J. Mater. Chem. A. 2016; 4: 13809-13813Crossref PubMed Google Scholar,41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google Scholar and UMCM-313,41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google Scholar which exhibited initial TOFs in between 8 and 14 molCEESmolchromophore−1min−1. The TOF values for Al-PMOF powder and Al-PMOF-textile were 9 and 170 molCEESmolchromophore−1min−1, respectively, showing a nearly 20-fold improvement in performance for the MOF fabric relative to the powder. The substantially improved rate for the MOF fabric is ascribed to more uniform illumination of the MOF catalyst when it is displayed on the fiber than when it is dispersed in solution via aggregation. Similarly, a recent report shows that photo-oxidation of CEES using UMCM-313 MOF catalyst proceeds 10-fold faster when the MOF is formed as a film on a planar substrate than as powder in solution (Table 1).41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google Scholar Importantly, our Al-PMOF film on fiber substrate shows even ∼2-fold higher photocatalytic activity than UMCM-313 film on flat substrate. This enhancement in catalytic performance is ascribed to the favorable arrangement of 2D Al-PMOF nanosheet crystals on fibers via our method. Images show that crystals are radially grown and effectively arranged with no aggregation on fiber surface (Figure S14), thus leading to greater local concentration of CEES per gram of MOF compared with micron-sized Zr6-based MOF films on a flat surface.42Lee D.T. Jamir J.D. Peterson G.W. Parsons G.N. Water-stable chemical-protective textiles via euhedral surface-oriented 2D Cu-TCPP metal-organic frameworks.Small. 2019; 15: 1805133Crossref PubMed Scopus (66) Google Scholar This distinct feature also enables a substantial exposure of Al-PMOF film to incident light with relatively less light scattering,43Heinke L. Wöll C. Surface-mounted metal-organic frameworks: crystalline and porous molecular assemblies for fundamental insights and advanced applications.Adv. Mater. 2019; 31https://doi.org/10.1002/adma.201806324Crossref PubMed Scopus (103) Google Scholar therefore effectively generating 1O2 to oxidize CEES. To the best of our knowledge, this is the first study to both substantiate an Al-based MOF as a promising photocatalyst and demonstrate Al-PMOF/fiber catalyst with prominently enhanced photocatalytic activity in CEES detoxification. In addition, the composite catalyst with flexible polymeric fiber components would be suitable for field-deployable applications, as they are less brittle and more flexible than other composite ceramic fibrous scaffold materials.44Nakahama M. Reboul J. Kamei K.I. Kitagawa S. Furukawa S. Fibrous architectures of porous coordination polymers-alumina composites fabricated by coordination replication.Chem. Lett. 2014; 43: 1052-1054Crossref Scopus (15) Google ScholarTable 1Comparison of Half-Lives of CEES Oxidation under Light Irradiation and O2 Environment Using MOF Powders or MOF Films Coated on Substrates as CatalystsMaterialCatalystCatalyst/CEES Ratio (mol %)SolventPhotosensitizerPhotoirradiation (LED) TypeHalf-Life (min)ReferencePowderPCN-2221MeOHporphyrinblue13Liu et al.19Liu Y. Howarth A.J. Hupp J.T. Farha O.K. Selective photooxidation of a mustard-gas simulant catalyzed by a porphyrinic metal-organic framework.Angew. Chem. Int. Ed. 2015; 54: 9001-9005Crossref PubMed Scopus (210) Google ScholarNU-10001MeOHpyreneUV6Liu et al.18Liu Y. Buru C.T. Howarth A.J. Mahle J.J. Buchanan J.H. DeCoste J.B. Hupp J.T. Farha O.K. Efficient and selective oxidation of sulfur mustard using singlet oxygen generated by a pyrene-based metal-organic framework.J. Mater. Chem. A. 2016; 4: 13809-13813Crossref PubMed Google Scholar[email protected]0.2MeOHBODIPYgreen2Atilgan et al.17Atilgan A. Islamoglu T. Howarth A.J. Hupp J.T. Farha O.K. Detoxification of a sulfur mustard simulant using a BODIPY-functionalized zirconium-based metal-organic framework.ACS Appl. Mater. Interfaces. 2017; 9: 24555-24560Crossref PubMed Scopus (83) Google ScholarNU-10000.5MeOHpyreneUV6Buru et al.41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google ScholarPCN-222/MOF-5450.5MeOHporphyrinblue11Buru et al.41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google ScholarUMCM-3130.5MeOHperyleneblue4Buru et al.41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google ScholarAg12TPyP0.01CD3ODporphyrinwhite1.5Cao et al.9Cao M. Pang R. Wang Q.-Y. Han Z. Wang Z.-Y. Dong X.-Y. Li S.-F. Zang S.-Q. Mak T.C.W. Porphyrinic silver cluster assembled material for simultaneous capture and photocatalysis of mustard-gas simulant.J. Am. Chem. Soc. 2019; 141: 14505-14509Crossref PubMed Scopus (113) Google ScholarAl-PMOF0.7MeOHporphyrinblue16this studyCompositeNU-1000 film on glass0.0032MeOHpyreneUV145Buru et al.41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google ScholarUMCM-313 film on glass0.0032MeOHporphyrinblue75Buru et al.41Buru C.T. Majewski M.B. Howarth A.J. Lavroff R.H. Kung C.-W. Peters A.W. Goswami S. Farha O.K. Improving the efficiency of mustard gas simulant detoxification by tuning the singlet oxygen quantum yield in metal-organic frameworks and their corresponding thin films.ACS Appl. Mater. Interfaces. 2018; 10: 23802-23806Crossref PubMed Scopus (54) Google ScholarAl-PMOF on fiber0.2MeOHporphyrinblue4this study Open table in a new tab The practical effectiveness of Al-PMOF/fiber composite can be extended to a colorimetric textile pH sensor, showing an instant and dramatic color change from maroon to green upon HCl vapor exposure (Figure 5D). The greenish color can immediately return to the original maroon color upon exposure to NH3 vapor given off from NH4OH solution (Figure 5D). The reversible color change is attributed to protonation/deprotonation of the nitrogen Lewis basic sites on the H2TCPP linker in Al-PMOF.28Wilcox O.T. Fateeva A. Katsoulidis A.P. Smith M.W. Stone C.A. Rosseinsky M.J. Acid loaded porphyrin-based metal-organic framework for ammonia uptake.Chem. Commun. (Camb.). 2015; 51: 14989-14991Crossref PubMed Google Scholar The adsorbed gas molecules can be removed by rinsing the composite materials in water and ethanol under stirring at 500 rpm for 10 min, with no MOF crystals peeling or dislodging from the fiber substrates. This shows that Al-PMOF films are strongly adhered to the fiber surface and reusable for the sensing application. The structural robustness of Al-PMOF after HCl exposure was also verified in a previous report.28Wilcox O.T. Fateeva A. Katsoulidis A.P. Smith M.W. Stone C.A. Rosseinsky M.J. Acid loaded porphyrin-based metal-organic framework for ammonia uptake.Chem. Commun. (Camb.). 2015; 51: 14989-14991Crossref PubMed Google Scholar The systematic exploration of reversible colorimetric and switchable pH response was implemented with PCN-222 containing H2TCPP as a linker.45Deibert B.J. Li J. A distinct reversible colorimetric and fluorescent low pH response on a water-stable zirconium-porphyrin metal-organic framework.Chem. Commun. (Camb.). 2014; 50: 9636-9639Crossref PubMed Google Scholar Furthermore, the Al-PMOF/fiber textile can be potentially exploited as an efficient adsorbent for organic solvents. As shown in Figure 5E, the chloroform droplets as a test solvent contaminated in water was rapidly and selectively absorbed by the MOF/fiber composite upon contact. The selective and immediate organic solvent suction over water is due to the relatively hydrophobic nature of the Al-PMOF film as demonstrated in the water isotherms of the MOF (Figure 1D) and in a simple test with water droplets cast on the composite surface (Figure 5E). In summary, for the first time we found Al-PMOF as a promising photocatalyst to generate reactive singlet oxygen species under LED irradiation, therefore rapidly and selectively oxidizing toxic CEES into non-hazardous CEESO. We further demonstrated surface-immobilized Al-PMOF thin films on polymeric non-woven textile substrates at relatively low temperature (120°C) by using a solid Al2O3 film conversion approach in a cosolvent system of DMF and water. The optimum solvent mixture allows beneficial surface hydrolysis of the Al2O3 and favorable solvation of the H2TCPP linker, allowing low-temperature synthesis of Al-PMOF textiles.