Enhancement of Aqua‐Ammonia Vapor on Proton Conduction for Two Water‐Tolerant Complicated Copper Cluster Compounds

Abstract

By adopting two similar acyl thiourea‐based carboxylate ligands, 2‐(3‐benzoylthioureido)propionic acid (H3BTPA) and 2‐(3‐benzoylthioureido)ethanoic acid (H3BTEA) to react with Cu(OAc)2, respectively, one 2D cluster polymer [CuI6CuII6(BTPA)6(H2O)10]n (1) and one 0D cluster [CuI6CuII6(BTEA)6(H2O)10(DMF)2]⋅6H2O (2) (DMF=N, N‐dimethylformamide) were successfully prepared and structurally characterized. The optimized proton conductivity for 1 is 1.16 × 10−5 S⋅cm−1 under 98% RH and 100 °C, which can be increased to a higher value of 7.70 × 10−4 S⋅cm−1 under aqua‐ammonia vapor from 2.0 M of NH3⋅H2O solution. For 2, the largest proton conductivity of 9.80 × 10−4 S⋅cm−1 could be obtained under aqua‐ammonia vapor. Through PXRD determinations, water and ammonia adsorption measurements, Ea calculations, a clear understanding of their proton conduction mechanisms as well as the enhancement of aqua‐ammonia vapor on the proton conduction has been obtained.

Multiple Strategies to Fabricate a Highly Stable 2D CuIICuI–Organic Framework with High Proton Conductivity

“…Nafion is the first and currently the most widely used proton conduction material . However, its large-scale applications are limited by its high cost and limited working temperatures. , Therefore, recently, researchers have been working on the design and development of alternatives.…”

“…Metal–organic frameworks (MOFs) offer diverse and highly regular network structures, and they provide abundant functionality , by changes in the metal ions and organic ligands. Thus, they have been applied in a wide variety of applications, − including use as proton conductors. − Two-dimensional (2D) MOFs have received an increasing amount of attention in recent years due to the exposure of the functional groups and the open interface . The large specific surface areas of 2D MOFs can provide more proton jumping sites, and the highly open interlayer channels also allow guest molecules carrying protons to enter, which synergistically improves proton transfer effectiveness .…”