Construction of oxygen-enriched graphitic carbon nitride polymers for highly efficient and selective H2O2 production via photocatalytic O2 reduction.

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The development of organic materials for visible light driven photocatalytic is regarded as one of the most promising avenues to solve environment and solar-energy utilization issue. Here, we present that one-dimensional supramolecular organic nanofibers, self-assembled by a carboxy-substituent perylene diimide (PDI) molecule through H-type π-π stacking and hydrogen bonding, can act as a robust and effective photocatalyst for both organic pollutants degradation and water oxidation under visible light without the apparent need for an added metal co-catalysts. We corroborate that the highly efficient and stable activity of such supramolecar photocatalyst are attributed to the introduction of terminal carboxyl group, which leads to well-defined and stable Htype π-π stacking, and constructs the internal electric field in supramolecular nanofibers, thereby resulting in the deepening of valence band (VB) and the enhancement of migration and separation efficiency of photo-induced charge carriers. Our findings may help the development of semiconducting-based organic supramolecular materials for applications in environment protection and water splitting.

Efficient organic solar cells (OSCs) often use combination of polymer donor and small molecule acceptor. Herein we demonstrate efficient and thermally stable OSCs with combination of small molecule donor and polymer acceptor, which is expected to expand the research field of OSCs. Typical small molecule donors show strong intermolecular interactions and high crystallinity, and consequently do not match polymer acceptors because of large-size phase separation. We develop a small molecule donor with suppressed π-π stacking between molecular backbones by introducing large steric hindrance. As the result, the OSC exhibits small-size phase separation in the active layer and shows a power conversion efficiency of 8.0%. Moreover, this OSC exhibits much improved thermal stability, i.e. maintaining 89% of its initial efficiency after thermal annealing the active layer at 180 °C for 7 days. These results indicate a different kind of efficient and stable OSCs.

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Four deep eutectic solvents (DESs) were synthesized, and 5–30% polyethylenimine (PEI) was added to make functional DESs (FDESs) for dynamic absorption experiments of hydrogen sulfide. The synthesized FDESs were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and nuclear magnetic resonance. The results demonstrated the successful synthesis of FDESs. The interaction between H2S and the FDESs was discussed at a molecular level via the quantum chemical calculations. It was noticed that FDESs prefer chemisorption on H2S. In this work, the 25% PEI/FDES@EG showed the highest desulfurization performance. The effects of H2S concentration and temperature on the desulfurization performance were investigated. It was found that a relatively low temperature (30 °C) was favorable for the absorption of H2S. The 25% PEI/FDES@EG could remove H2S efficiently over a low H2S concentration. Moisture played an important role in the FDES desulfurization system. The absorption/desorption cycle experiment indicated that the FDESs retain their good regeneration performance for at least five times.

HPLC-MS/MS method is sensitive and selective and can be suitable for the reliable quality control of Abri mollis Herba and Abri Herba.

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