Research on the electrochemical degradation and hydrogen generation of Fraxinus mandshurica by polyoxometalate

The efficient utilization of wood waste is important for protecting the environment and solving the energy shortage problem. Taking Fraxinus mandshurica (FM) as an example, polyoxometalate (POM) was used as a catalyst for cyclic redox in an H-type electrolytic cell, where wood was oxidized to valuable small-molecule chemicals at the anode and hydrogen was generated at the cathode. The system successfully recycles energy, simultaneously converting biomass to chemical and electrical to hydrogen. Furthermore, the effects of various factors on the reaction were also investigated to obtain the optimal electrochemical conversion results for wood waste. At the optimal conditions, the FM degradation rate of 56.1%, with aromatic organic and carbonyl compounds as the main products, and the average Faraday efficiency of hydrogen generation can reach 93%, saving about 40% of energy consumption compared to water electrolysis at 0.1 A cm−2. Therefore, this electrochemical conversion method provides a new potential pathway for the application of wood waste.</p

Ultrafast Electron Transfer from Upper Excited State of Encapsulated Azulenes to Acceptors across an Organic Molecular Wall

In the context of generating reactive organic radical cations within a confined capsule and exploring photoinduced electron transfer from encapsulated organic molecules to organic and inorganic acceptors through an organic molecular wall, we have investigated electron transfer from the upper excited state (S₂) of azulene (Az) and guaiazulene (GAz) enclosed within an octa acid (OA) capsule to water-soluble 4,4′-dimethyl viologen²⁺ (MV²⁺) and pyridinium⁺ (Py⁺) salts or colloidal TiO₂. S₂ fluorescence of OA encapsulated Az and GAz was quenched by electron acceptors such as MV²⁺ and Py⁺ salts. That electron transfer is responsible for S₂ fluorescence quenching was established by recording the transient absorption spectrum of the MV^●+ in the femtosecond time regime. Femtosecond time-resolved fluorescence experiments suggested that the time constant for the forward and reverse electron transfer from encapsulated Az and GAz to MV²⁺ is 4 and 3.6 ps, and 55.7 and 36.9 ps, respectively. The observed S₂ fluorescence quenching by colloidal TiO₂ in aqueous buffer solution is attributed to electron transfer from encapsulated Az and GAz to TiO₂. Lack of quenching by the wider band gap material ZrO₂ supported the above conclusion. FT-IR-ATR experiments confirmed that OA capsules containing Az and GAz can be adsorbed on TiO₂ films, and excitation of these resulted in S₂ fluorescence quenching. The observations presented here are important in the context of establishing the value of OA type cavitands where charge separation and donor shielding are critical