Proton conductive metal phosphonate frameworks

This review covers basic design principles and offers a cross-section of the current status of phosphonate MOFs as proton conductors. Metal phosphonates are often sustained by strong bonds that render them very stable materials. The phosphonate group can also coordinate as a protonated species. These factors, coupled with the inherent structural versatility intrinsic to any metal organic framework family, are the foundation of their interest as proton conducting materials. This review summarizes the recent progress in this topical field as well as some of the existing challenges for further development. The present state of application of the materials is still largely in the academic domain but increasingly, new structures with the necessary proton conducting ability and stability to merit further development as membranes are being reported. The review concludes with a discussion of future challenges for development of this promising field. (C) 2017 Elsevier B.V. All rights reserved.