A robust zirconium amino acid metal-organic framework for proton conduction

Abstract

Proton conductive materials are of significant importance and highly desired for clean energy-related applications. Discovery of practical metal-organic frameworks (MOFs) with high proton conduction remains a challenge due to the use of toxic chemicals, inconvenient ligand preparation and complication of production at scale for the state-of-the-art candidates. Herein, we report a zirconium-MOF, MIP-202(Zr), constructed from natural α-amino acid showing a high and steady proton conductivity of 0.011 S cm−1 at 363 K and under 95% relative humidity. This MOF features a cost-effective, green and scalable preparation with a very high space-time yield above 7000 kg m−3 day−1. It exhibits a good chemical stability under various conditions, including solutions of wide pH range and boiling water. Finally, a comprehensive molecular simulation was carried out to shed light on the proton conduction mechanism. All together these features make MIP-202(Zr) one of the most promising candidates to approach the commercial benchmark Nafion.

Improving MOF stability: approaches and applications

“…Not limited to acids, NH 3 and amino were also modied within MOFs via the de novo process or post-synthetic strategy, improving their proton-conducting ability. 223,224 Wang et al reported a highly stable MOF, MIP-202(Zr), assembled by L-aspartate and Zr 4+ and investigated its proton-conduction properties at 90 C and 95% RH. 224 The interaction between NH 3 + groups (proton source) and water molecules in the cavities generated an extended hydrogen-bonded network in MIP-202(Zr), endowing it with a desirable and steady proton conductivity of 0.011 S cm À1 .…”

“…223,224 Wang et al reported a highly stable MOF, MIP-202(Zr), assembled by L-aspartate and Zr 4+ and investigated its proton-conduction properties at 90 C and 95% RH. 224 The interaction between NH 3 + groups (proton source) and water molecules in the cavities generated an extended hydrogen-bonded network in MIP-202(Zr), endowing it with a desirable and steady proton conductivity of 0.011 S cm À1 . Hong and co-workers utilized a microwave-assisted solvothermal reaction to obtain Ni-MOF-74, which remained stable even at a pH value as low as 1.8.…”

Conductive metal‐organic frameworks: Recent advances in electrochemical energy‐related applications and perspectives

“…Besides, the K 3 Fe 2 [PcFe‐O 8 ] (K 3 Fe 2 [(2,3,9,10,16,17,23,24‐octahydroxy phthalocyaninato)Fe]) is also synthesized by dissolving PcFe‐OH 8 , iron acetate, and potassium acetate in the mixed solution of N ‐methyl‐2‐pyrrolidone (NMP)/H 2 O at 150°C 45 . Another zirconium‐MOF, that is, MIP‐202(Zr), is also achieved at 120°C 48 . One particularly notes that several conductive MOFs even can be obtained at lower temperatures, the M 2 (BOBDC)(DMF) 2 (M = Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ; H 4 DOBDC = 2,5‐dihydroxybenzene‐1,4‐dicarboxylic acid; DMF = N,N ‐dimethylformamide), M 2 (DSBDC)(DMF) 2 (M = Mn 2+ , Fe 2+ ; H 2 DSBDC = 2,5‐disulfhydrylbenzene‐1,4‐dicarboxylic acid), M 2 Cl 2 (BTDD)(DMF) 2 (M = Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ ; H 2 BTDD = bis(1H‐1,2,3‐triazolo[4,5‐b],[4′,5′‐i]dibenzo[1,4]dioxin)), and M(1,2,3‐triazolate) 2 (M = Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Cu 2+ , Zn 2+ , Cd 2+ ) all acquired under freezing in Ar atmosphere 40,49 .…”

Water-based routes for synthesis of metal-organic frameworks: A review

“…This method is expected to realize the breakthrough of high-performance production of Zr-MOFs from the laboratory scale to industrial production. Another example of the green scalable synthesis of Zr-MOFs was reported by Wang et al [155], who reported a green and scalable method to synthesize a stable amino acid-based Zr-MOFs (Zr-MIP-202) at reflux conditions. The STY of the obtained Zr-MIP-202 was as high as 7000 kg m −3 per day, which is higher than that of Al-MOFs currently being produced on ton scale (>1000 m (363 K, 95% relative humidity (RH)).…”