Molecular Engineering of Perylene Diimide Polymers with a Robust Built-in Electric Field for Enhanced Solar-Driven Water Splitting.

The built-in electric field of the polymer semiconductors could be regulated by the dipole moment of its building blocks, thereby promoting the separation of photogenerated carriers and achieving efficient solar-driven water splitting. Herein, three perylene diimide (PDI) polymers, namely oPDI, mPDI and pPDI, are synthesized with different phenylenediamine linkers. Notably, the energy level structure, light-harvesting efficiency, and photogenerated carrier separation and migration of polymers are regulated by the orientation of PDI unit. Among them, oPDI enables a large dipole moment and robust built-in electric field, resulting in enhanced solar-driven water splitting performance. Under simulated sunlight irradiation, oPDI exhibits the highest photocurrent of 115.1 µA cm-2 for photoelectrochemical oxygen evolution, which is 11.5 times that of mPDI, 26.8 times that of pPDI and 104.6 times that of its counterparts PDI monomer at the same conditions. This work provides a strategy for designing polymers by regulating the orientation of structural units to construct efficient solar energy conversion systems.

Highly selective photocatalytic oxidation of alcohols under the application of novel metal organic frameworks (MOFs) based catalytic system.

Carboxylic acid is one of the most crucial and widely used organic chemicals in daily human life activities. Hence preparation of this important chemical was performed under the application of the highly selective photo-catalysts through oxidation of alcohols to carboxylic acids. Herein, we have designed and disclosed a binary NH2-MIL-125(Ti)/ NaBr) catalyst system to realize the effective transformation of alcohols into carboxylic acids under visible light irradiation. Hence, derivatives of benzyl alcohol containing either electron withdrawing and donating groups as well as aliphatic primary alcohols were effectively converted into the corresponding carboxylic acids. Based on our findings, NH2-MIL-125(Ti) based photocatalytic system has shown efficient and highly selective activities for oxidation of alcohol especially the in-situ conversion of co-catalyst NaBr into the corresponding free radical can enhance the alcohol oxidation performance of the catalytic system.