Hydrothermal Synthesis of a Novel 2D‐Layered Vanadium Pyrophosphate With Multi‐Channel and Outstanding Proton Transport Properties

ABSTRACT A novel vanadium pyrophosphate, (C 6 H 14 N 2 )[(VO)P 2 O 7 ] (denoted as 1 ), has been successfully synthesized via a one‐step hydrothermal method at 180°C. The compound exhibits a unique two‐dimensional (2D) layered architecture formed by the interconnection of helical one‐dimensional (1D) [(VO)P 2 O 7 ] 2− anionic chains and protonated C 6 H 14 N 2 2+ cations. Structural analysis reveals that the 1D chains are constructed through corner sharing of VO 5 square pyramids and P 2 O 7 pyrophosphate units. The protonated cations further assemble with these chains via hydrogen‐bonding interactions, generating a 2D framework with distinct rhombic, flower‐like, and rectangular channels along the crystallographic c ‐, b ‐, and a ‐axes, respectively. Notably, the hydrogen‐bonded network within this framework facilitates efficient proton conduction, achieving a conductivity of 3.3 × 10 −4 S cm −1 at 50°C and 100% relative humidity (RH). Electrochemical studies demonstrate that the compound 1 /Nafion composite exhibits significantly enhanced redox peak intensities in cyclic voltammetry (CV) compared to pristine Nafion membranes, clearly verifying its efficacy as a proton conductive medium. Furthermore, the proton transport mechanism was identified as a vehicle‐type process, supported by an activation energy of 1.66 eV derived from Arrhenius analysis.