A sulfonic-acid-based covalent organic framework (TpPa-SO3H) has been synthesized that exhibits intrinsic proton conductivity under anhydrous conditions. The sulfonic acid groups are aligned on the two-dimensional (2D) layers at periodic intervals and promote the proton hopping inside the hexagonal one-dimensional channel. The intrinsic proton conductivity of TpPa-SO3H was measured as 1.7 × 10-5 S cm-1 at 120°C under anhydrous conditions. To enhance the proton conductivity, we have synthesized a hybrid COF TpPa-(SO3H-Py) by a ligand-based solid-solution approach that contains sulfonic acid as the acidic site, as well as pyridine as the basic site, in order to immobilize acidic proton carrier molecules. Impregnation of phytic acid molecules inside the framework increases the anhydrous proton conductivity up to 5 × 10-4 S cm-1 at 120°C. Such an approach highlights the advantage and first-time use of hybrid COF for interplaying intrinsic to extrinsic proton conductivity.
Bibliographical noteFunding Information:
R.B. acknowledges DST (No. SR/S1/IC-22/2009), DST Indo-Singapore Project (No. INT/SIN/P-05), DST Nanomission Project (No. SR/NM/NS-1179/2012G), and CSIR [Nos. CSC0122 and CSC0102] for funding. S.C. acknowledges UGC for SRF. T.K. and K.D. acknowledge CSIR (New Delhi, India) for SRF and JRF, respectively. S.C. acknowledges Mr. Bidhan Chandra Patra for help in synthesis, and R.B. acknowledges Ms. Harshitha Barike Aiyappa and Dr. Sreekumar Kurungot for their help with proton conduction.
© 2016 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry