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Description
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Two-dimensional covalent organic frameworks (2D-COFs) and conjugated polymers represent an emerging class of organic materials with well-defined periodic architectures, extended π-conjugation, and high chemical robustness, making them promising for electrocatalysis and energy-conversion technologies. Herein, we report a solvent-free, vapor-phase route for the synthesis of porphyrin-based donor–acceptor 2D polymer thin films via solid–vapor Schiff-base condensation. Free-base and Ni-metalated 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP and NiTAPP) were reacted with thieno[3,2-b]thiophene-2,5-dicarbaldehyde (ThDAL) under reduced pressure to form extended imine-linked networks (PP-Th and NiPP-Th) directly on solid substrates. Spectroscopic and surface analyses (FTIR, UV–Vis, XPS, and LDI-HRMS) confirm successful imine bond formation, preservation of the porphyrin core, and the emergence of donor–acceptor electronic coupling across the 2D framework. The resulting vapor-grown films exhibit reduced optical band gaps and favorable band alignment for oxygen redox reactions. Notably, NiPP-Th demonstrates significantly enhanced photo-assisted oxygen evolution reaction (OER) activity, with lower charge-transfer resistance, reduced Tafel slopes, higher electrochemically active surface area, and superior operational stability compared to metal-free analogues. These results highlight vapor-phase porphyrin polymerization as a versatile strategy to access robust, substrate-bound 2D electrocatalysts with tunable electronic structure. (2026-04-08)
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