Improving proton conduction of the Prussian blue analogue Cu3[Co(CN)6]2·nH2O at low humidity by forming hydrogel composites. Issue 9 (18th March 2021)

• Record Type: Journal Article
• Authors: Qiao, Qiao; Wang, Hua-Jiang; Li, Cui-Ping; Wang, Xiao-Zu; Ren, Xiao-Ming
• Is Part Of: Inorganic chemistry frontiers. Volume 8:Issue 9(2021)
• Page Start: 2305
• Page End: 2314
• Publication Date: 2021-03-18
• Subjects: Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1qi00070e
• Languages: English
• ISSNs: 2052-1553

Abstract

Abstract : Composites of Prussian blue analogue (PBA) adsorbed imidazole-acetic acid with polyvinyl alcohol hydrogel show excellent water-retention capacity and fast proton conduction at 25% RH in 298–353 K, herein X is the mass ratio of PBA to hydrogel. Abstract : In this study, we have synthesized Prussian blue analogue nanocrystals of copper hexacyanocobaltate (CuHCC), and their derivatives via a facile stepwise encapsulation of 1, 3-diaza-2, 4-cyclopentadiene (Im; Im@CuHCC) and acetic acid (HAc; Im-HAc@CuHCC) into the CuHCC framework. These materials were characterized by powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, N2 adsorption/desorption and scanning electron microscopy. Im-HAc@CuHCC shows humidity dependent proton conduction with conductivity ( σ ) in the 0.933–8.55 × 10 −2 S cm −1 range at 98% relative humidity (RH) while σ ≈ 10 −6 –10 −5 S cm −1 at 25% RH in the 298–353 K range. We further prepared and characterized a series of composites of Im-HAc@CuHCC with a polyvinyl alcohol (PVA) hydrogel, labeled Im-HAc@CuHCC-PVA- X ( X = 0, 2, 5 and 10%, and represents the mass ratio of Im-HAc@CuHCC and the hydrogel). Regarding PVA hydrogel, the tensile strength of composites is enhanced at least 1.5 times. Importantly, the X = 10% composite shows superior proton conduction with σ = 0.81–6.5 × 10 −2 S cm −1 at 25% RH in the 298–353 K range, confirming that the formation of the hydrogel composite is a facile but efficient strategy to enhance the water-retention capacity and proton conduction at low humidity for porous proton conductors.