Work

Chelate Anchoring at Open Sites of Zirconium‐Oxo Cluster by Bifunctional Carboxyl‐Sulfonyl Ligand Enhancing Stability and Proton Conductivity in MOF Fibrous Membrane

Year: 2026

Type: article

Abstract: ABSTRACT Developing high‐performance metal–organic framework (MOF) ‐based proton exchange membranes requires balancing proton conductivity and stability. Conventional sulfonation often compromises framework integrity by treating ‐SO 3 H groups only as proton donors. Herein, a chelate anchoring strategy uses a bifunctional carboxyl‐sulfonyl ligand that firmly binds to open metal sites on zirconium‐oxo clusters. Carboxylate groups chelate to Zr 6 ‐oxo clusters to form robust Zr 6 ‐O‐O'‐C‐CH 2 ‐SO 3 H linkages, significantly enhancing structural stability, while pendant ‐SO 3 H groups act as efficient proton carriers. Aliovalent metal substitution and dimethyl‐functionalization of the ligand further reinforce rigidity. The resulting Zr‐TPTC(Me 2 )‐SO 3 H exhibits exceptional thermal stability (827.80 K), surpassing both In‐TPTC(Me 2 ) (702.27 K) and Zr‐TPTC(Me 2 )‐SO 3 H ( 821.40 K). Well‐anchored ‐SO 3 H groups, in concert with adsorbed water, establish dense hydrogen‐bonding networks (‐SO 3 H⋯H 2 O), enabling ultrahigh proton conductivity of 6.15 × 10 −2 S cm −1 at 338 K and 95% RH, with a low activation energy (0.29 eV). Theoretical simulations corroborate enhanced water binding energy of ∆ E = ‐53.17 kcal mol −1 and extensive hydrogen‐bonding interactions that stabilize the Zr 6 clusters and facilitate efficient proton transport. Electrospinning with poly(vinyl alcohol) (PVA) yields flexible Zr‐TPTC(Me 2 )‐SO 3 H@PVA hybrid membranes, demonstrating promising practical applicability. This work provides a new paradigm for functional MOFs that transcends conventional sulfonation strategies by integrating structural reinforcement with proton conduction functionality.

Source: Advanced Functional Materials

DOI: 10.1002/adfm.74451

Authors: Ling Yu, Hui Gao, Fu‐Qiang Zhang, Xian‐Ming Zhang

Institutions: Shanxi Normal University, Changzhi Medical College, Yuncheng University

Language: English

Topic: Fuel Cells and Related Materials

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: bronze

Funder: National Natural Science Foundation of China

Award: G6072333906