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A novel fluorinated diamine monomer (FPMDA ) was synthesized from p-fluorobenzaldehyde and 2, 6-dimethylaniline, and then reacted with pyromellitic anhydride to obtain a fluorinated polyimide (FPI). The structures of the synthesized FPMDA diamine monomer and polyimide were characterized by FTIR, nuclear magnetic hydrogen spectroscopy, and mass spectrometry (MS) ;the thermal properties of the polyimide film were characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results showed that FPI has excellent solubility in solvents such as DMF, NMP, and THF. FPI also shows good thermal stability, under nitrogen environment, with thermal decomposition temperature Td5% of 550 °C, Td10% of 580 °C, and char yield of 58.7% at 1 000 °C, its glass transition temperature is greater than 400 °C . [ABSTRACT FROM AUTHOR]

Due to the advantages of non-toxicity, high chemical stability, high activity and low cost, TiO2 is deemed as ideal material for photocatalytic degradation. However, due to its relatively high band-gap energy, anatase TiO2 can only absorb UV light and light with higher energy. In this work, the anatase TiO2 particles were decorated with two organic photosensitizers hemin and eosin Y. The morphology and chemical structure of the composites were verified by SEM, XRD patterns and Raman spectra, the light absorption ability and generation of free radicals were also investigated. The band-gap energy of TiO2, hemin/TiO2 and EY/TiO2 were found to be 2.82 eV, 0.72 eV and 0.95 eV, respectively. Additionally, absorption of more visible light and generation of more superoxide radicals were achieved after decoration of photosensitizers. Consequently, the photocatalytic degradation activity was largely improved, when the TiO2 particles was decorated with 3% of hemin, the degradation rate of methyl blue reached 76.89% and 63.82% in 120 min under UV light and visible light, respectively, which were 1.86 and 1.84 times that of neat TiO2. Comparatively, the ferric ions in hemin may capture the electrons generated by TiO2 and then deliver the electrons to oxygen to generate more superoxide radicals, thus hemin/TiO2 exhibits higher photocatalytic degradation activity than EY/TiO2. [ABSTRACT FROM AUTHOR]

Modulating the electronic structure of the electrocatalyst plays a vital role in boosting the electrocatalytic performance of the oxygen evolution reaction (OER). In this work, we introduced a one-step solvothermal method to fabricate 1,1-ferrocene dicarboxylic acid (FcDA)-decorated self-evolved nickel sulfide (Ni 3 S 2 ) nanosheet arrays on a nickel foam (NF) framework (denoted as FcDA-Ni 3 S 2 /NF). Benefiting from the interconnected ultrathin nanosheet architecture, ligand dopants induced and facilitated in situ structural reconstruction, and the FcDA-decorated Ni 3 S 2 (FcDA-Ni 3 S 2 /NF) outperformed its singly doped and undoped counterparts in terms of OER activity. The optimized FcDA-Ni 3 S 2 /NF self-supported electrode presents a remarkably low overpotential of 268 mV to achieve a current density of 10 mA cm -2 for the OER and demonstrates robust electrochemical stability for 48 h in a 1.0 M KOH electrolyte. More importantly, in situ electrochemical Raman spectroscopy reveals the generation of catalytically active oxyhydroxide species (NiOOH) derived from the surface construction during the OER of pristine FcDA-Ni 3 S 2 /NF, contributing significantly to its superior electrocatalytic performance. This study concerns the modulation of electronic structure through ligand engineering and may provide profound insight into the design of cost-efficient OER electrocatalysts.