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    Hydrophilic porous organic polymers with fluorene-viologen units for enhanced photocatalytic hydrogen production
    (Elsevier, 2025) Altinisik, Sinem; Yildiz, Gizem; Turgut, Kubra; Yayla, Cansu; Patir, Imren Hatay; Koyuncu, Sermet
    The rising energy demand and environmental concerns have intensified the search for clean energy solutions. Photocatalytic water splitting offers a promising route, yet efficiency remains limited by the need for advanced photocatalysts with enhanced light absorption, charge separation, and water interaction. Porous organic polymers (POPs) are emerging as efficient materials for solar energy conversion due to their ordered conjugated structures. This study explores the impact of a ketone moiety on the hydrophilicity and photocatalytic hydrogen evolution efficiency of fluorene-bridged bicarbazole-viologen-based POPs (POP-MB-TP(DCzFO) and POP-MB-TP (DCzF)). Our results show that POP-MB-TP(DCzF) achieves a hydrogen evolution rate of 3.37 mmol g- 1 h- 1, nearly twice that of POP-MB-TP(DCzFO) (1.72 mmol g- 1 h- 1). This improvement highlights the role of hydrophilicity in charge transport and catalytic efficiency, providing insights for designing highly efficient organic photocatalysts for sustainable hydrogen production.
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    Light driven photocatalytic hydrogen generation using BODIPY-thiophene-covalent organic polymers
    (Pergamon-Elsevier Science Ltd, 2025) Turgut, Ki bra; Ozdemir, Mucahit; Yildiz, Gizem; Yalcin, Bahattin; Koyuncu, Sermet; Koksoy, Baybars; Patir, Imren Hatay
    Boron-dipyrromethene (BODIPY)-based dyes have recently garnered attention as sensitizers for photocatalytic hydrogen production. They exhibit high catalytic activity through efficient electron transfer, owing to their unique properties such as high molar absorptivity, adjustable absorption and emission energies, and high fluorescence quantum efficiencies. In this study, the effect of a-OH subunit that can increase hydrophilicity on the photocatalytic hydrogen evolution in BODIPY-thiophene-based covalent organic polymers (COP) was investigated. In the conducted research, COP structures were integrated into BODIPY to enhance their light absorption capabilities, aiming to serve as photocatalysts for energy conversions under simple conditions. In the proposed system, Thiophene-BODIPY-based dyes are integrated into COP structures, where they facilitate electron excitation upon light absorption, thereby playing an effective role in photocatalytic reactions by promoting electron transfer. The photocatalyst, modified with titanium dioxide (TiO2) nanoparticles, exhibited notable performance in enhancing the efficiency of the hydrogen production process, owing to its light absorption capabilities, multifunctional fluorescent properties, and electron-accepting characteristics. The synthesized BODIPY-Th-COP-OH_TiO2 photocatalyst demonstrated higher hydrogen activity compared to BODIPY-Th-COP-CH3_TiO2, attributed to the presence of hydroxyl groups promoted hydrophilic character in the catalyst structure. Therefore, BODIPY-Th-COP-X_TiO2 photocatalysts (X: OH, CH3) utilizing methanol as sacrificial agent yielded hydrogen amounts of 0.197 mmol g-1 h-1 and 0.132 mmol g-1 h-1 for BODIPY-Th-COP-OH_TiO2 and BODIPY-Th-COP-CH3_TiO2 photocatalysts, respectively, under visible light illumination.