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Abstract:The functional application of metallic glasses in the catalytic field has widely attracted research attention due to its unique atomic structure compared to crystalline materials. It has been reported that metallic glasses can effectively activate H 2 O 2 and persulfate, yet the activation of peroxymonosulfate by metallic glasses is not studied well. In this work, the metallic glass with atomic composition of Fe 78 Si 9 B 13 was applied for investigating the peroxymonosulfate (PMS) activation on degradation of naphthol green B (NGB) dye. The change of surface morphology indicated the important role of oxide films during the dye degradation. The effects and first-order kinetics model of various reaction parameters were evaluated systematically, including PMS concentration, catalyst dosage, irradiation intensity, and dye concentration. The results showed that about 98% of the dye removal rate could be achieved only within 10 min under rational conditions. The reaction kinetics k of 0.1339 min −1 without ribbons was sharply improved to 0.3140 min −1 by adding 0.5 g/L ribbons, indicating the superior activation ability of Fe 78 Si 9 B 13 metallic glass. The recycling experiment revealed that the Fe 78 Si 9 B 13 ribbons exhibited the excellent surface stability and catalytic reusability for activating PMS even after reused for 10th run.

The mechanisms of electron transport and back-reaction in dye-sensitized solar cells (DSCSs) are investigated by intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS). The DSCSs with and without TiCl4-treated nanoporous TiO2 films are measured by IMPS/IMVS. The results indicate that the electron lifetime (n), the diffusion coefficient (Dn), the diffusion length (Ln), the incident photon to current efficiency (IPCE) and the photoinduced charge (Qoc) increase markedly, while the dark current and the electron transit time (d) decreases for the TiCl4-treated nanoporous TiO2 films. The influence of TiCl4-treatment of nanoporous TiO2 film on the electron generation, the transport and the recombination processes is investigated at a microscopic level.

For the dye-sensitized solar cells (DSSCs), trap states exist in the TiO2 based photoanode and play an important role on the dynamic process of charge transport and recombination in the DSSCs. Generally, trap states mainly result from impurities, interface adsorption of ions, the breakdown of the lattice periodicity in the semiconductor, dangling bonds and/or the rearrangement of surface atoms. In this paper, we compare trap states of different nanoparticles based TiO2 photoanode films. The result of X-ray photoelectron spectroscopy (XPS) indicates that Ti3+ and the content of oxygen vacancies in the porous films decrease with the increase of particle sizes. Furthermore, to confirm the difference of trap states in these photoanodes, the measurements of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed. It is found that compared with the larger particle size, the TiO2 photoanode films based on the smaller nanoparticles possess more trap states. This research provides a useful description of microscopic mechanism for the effect of porous films with different sizes on cell photovoltaic performances.