Bor-dipirometen (BODIPY) boyalari kullanilarak fotokatalitik hi̇drojen üretimi

Today, the growing global reliance on fossil fuels to meet energy demands has led to a wide range of environmental problems, including air pollution, greenhouse gas emissions, water and soil contamination, ecosystem degradation, and acid rain, all of which also pose significant threats to human health. Therefore, transitioning to sustainable energy sources and enhancing energy efficiency have become critical requirements for reducing environmental impacts. Hydrogen energy has emerged as a promising clean energy carrier for the future. Among innovative methods, photocatalytic hydrogen production represents a sustainable approach that enables hydrogen generation through the decomposition of water using solar energy. In this process, semiconductor photocatalysts such as titanium dioxide (TiO2) are commonly employed; however, due to their wide band gap, they can only be activated under ultraviolet (UV) light, limiting their efficiency under visible light irradiation. To overcome this limitation, dye-sensitized systems capable of being excited by visible light have been developed and integrated into photocatalytic platforms. In this thesis, the use of boron-dipyrromethene (BODIPY)-based dyes, which exhibit high activity under visible light, was investigated as sensitizers for photocatalytic hydrogen production. BODIPY dyes possess superior optoelectronic properties such as high molar absorptivity, tunable absorption/emission wavelengths, and high fluorescence quantum yields, which enable efficient electron transfer and enhanced photocatalytic performance. In this study, BODIPY-thiophene-based covalent organic polymer (COP) structures were synthesized and functionalized with hydroxyl (-OH) groups to increase hydrophilicity, and were subsequently used as photocatalysts. These COP structures were combined with BODIPY units to enhance light absorption and supported with TiO2 nanoparticles to form composite photocatalytic systems. The resulting BODIPY-Th-COP-OH_TiO2 photocatalyst demonstrated superior hydrogen evolution performance compared to BODIPY-Th-COP-CH3_TiO2, attributed to the hydrophilic nature imparted by hydroxyl groups. Under visible light irradiation with methanol as the sacrificial agent, hydrogen production rates of 0.197 mmol g-1 h-1 and 0.132 mmol g-1 h-1 were achieved for BODIPY-Th-COP-OH_TiO2 and BODIPY-Th-COP-CH3_TiO2, respectively. The findings of this study demonstrate that the photocatalytic performance of BODIPY-based dyes can be optimized through functional modification, offering an effective strategy for sustainable hydrogen production. This work emphasizes the importance of innovative material design in environmentally friendly energy generation and contributes to the development of next-generation photocatalysts operable under visible light.