RESUMO
Exploration of high-performance photoanodes is considered as an essential challenge in photoelectrochemical (PEC) water splitting due to the complex four-electron reaction in water oxidation. Herein, the nano-structured WO3-Se heterojunction decorated by organic Nafion layer is designed. The optimized WO3-Se200-0.05Nafion photoanode shows a remarkable photocurrent of 1.40 mA cm-2at 1.23 V versus reversible hydrogen electrode, which is 2.5-fold higher than that of pure WO3nanosheets (WO3NS) photoelectrode. Remarkably, the photocurrent increments of WO3-Se200-0.05Nafion is larger than the increment sum of WO3-Se200 and WO3-0.05Nafion, which affirming the synergistic effect of Se nanospheres and Nafion layer. The improved PEC performances are attributed to the quick charge separation and transfer, the increased electric conductivity, and the excellent kinetics of oxygen evolution, which is derived from the strong interaction among WO3, Se and Nafion. Meanwhile, the better visible-light harvesting from Se nanospheres as photosensitizer and the induction of transparent Nafion as a passivation layer can explain this synergy. It hopes this heterostructure design with organic Nafion decoration can inspire to exploit outstanding performance photoanodes for PEC water splitting.
RESUMO
Nowadays, high value-added and multifunctional textiles have attracted widespread attention due to the changing demands of modern life. This study focused on the fabrication of silk with photochromism, flame retardancy, UV resistance and durability using riboflavin sodium phosphate (RSP) and various metal ions (Fe2+, Fe3+, Al3+, and Ti4+). Attractively, the photochromic performance was one of the most distinctive features of the modified silk, and the yellow silk fabric turned into fluorescent green under UV lamp. After a detailed comparison, it was determined that RSP/Fe3+ hybrid system was most effective in improving anti-UV performance of the silk with a high UPF of 25.8, achieving a "Good" level of UV protection. Specifically, it achieved a B1 fire protection with a low damaged-length of 9.4 cm and a high LOI of 28.3 %. Additionally, the modified silk showed the lowest smoke density, reducing by approximately 84.1 % versus that of pristine silk. Moreover, the modified silk was able to meet the B1 classification and the "Good" UV protection requirements even after 75 washing cycles, making it more durable than most functional textiles reported. The further analysis indicated that RSP and metal ions can synergistically enhance the condensed-phase action, thereby improving the fire resistance of silk.
Assuntos
Seda , Têxteis , Têxteis/análise , ÍonsRESUMO
Transforming glyoxal to value-added glyoxylic acid (GA) is highly desirable but challenging due to the uncontrollable over-oxidation. In this work, we report on a first demonstration of semi-oxidation of glyoxal with high selectivity (86.5%) and activity on WO3 nanoplate photoanode through the photoelectrochemical strategy. The optimization of reactivity was achieved via crystal facet regulation, showing a satisfactory GA production rate of 308.4 mmol m-2 h-2, 84.0% faradaic efficiency, and 4.3% total solar-to-glyoxylic acid efficiency on WO3 with enriched {200} facets at 1.6 V versus RHE. WO3 with a high {200} facet ratio exhibits more efficient electron-hole transfer kinetics, resulting in the facilitated formation of hydroxyl radicals (â¢OH) and glyoxal radicals. Meanwhile, the theoretical calculation results indicate that the high selectivity and activity come from the strong adsorption ability for glyoxal and the low reaction energy for glyoxal radical generation on the (200) facets of WO3. Moreover, the high energy demand toward oxalic acid production on WO3 leads to the exciting semi-oxidation process.