高产且稳定的共价有机骨架(COF)材料的便捷,环保的制造一直限制了它们的大规模生产和应用。在这项工作中,球磨用于在环境温度下通过1,3,5-三甲酰基间苯三酚(Tp)和三聚氰胺(MA)之间的机械化学反应合成COF。研究了不同的途径(无液体,溶剂辅助和催化剂辅助)和液体(溶剂或催化剂)的比例。当在研磨过程中添加各种量的液体时,获得了两种形态。两种形式是交织的线状和脱落的薄带状结构。此外,研究了COFs两种结构的可见光光催化性能(λ> 400 nm)和机理。剥落的带状结构表现出较高的苯酚光降解率,并且在使用四次后仍保留了初始光降解的87.6%。液体催化剂的加入不仅改善了COF材料的结晶度,而且提高了光催化反应的速率。通过球磨合成的TpMA的剥离结构的光催化活性与使用溶剂热法制备的光催化剂相当,而制备催化剂的时间缩短了36倍,溶剂用量减少了8-在室温下折叠。机械化学合成是大规模生产COF的有前途的潜在工具,它将更多地利用COF降解污染物。使用四次后,初始光降解的6%。液体催化剂的加入不仅改善了COF材料的结晶度,而且提高了光催化反应的速率。通过球磨合成的TpMA的剥离结构的光催化活性与使用溶剂热法制备的光催化剂相当,而制备催化剂的时间缩短了36倍,溶剂用量减少了8-在室温下折叠。机械化学合成是大规模生产COF的有前途的潜在工具,它将更多地利用COF降解污染物。使用四次后,初始光降解的6%。液体催化剂的加入不仅改善了COF材料的结晶度,而且提高了光催化反应的速率。通过球磨合成的TpMA的剥离结构的光催化活性与使用溶剂热法制备的光催化剂相当,而制备催化剂的时间缩短了36倍,溶剂用量减少了8-在室温下折叠。机械化学合成是大规模生产COF的有前途的潜在工具,它将更多地利用COF降解污染物。通过球磨合成的TpMA的剥离结构的光催化活性与使用溶剂热法制备的光催化剂相当,而制备催化剂的时间缩短了36倍,溶剂用量减少了8-在室温下折叠。机械化学合成是大规模生产COF的有前途的潜在工具,它将更多地利用COF降解污染物。通过球磨合成的TpMA的剥离结构的光催化活性与使用溶剂热法制备的光催化剂相当,而制备催化剂的时间缩短了36倍,溶剂用量减少了8-在室温下折叠。机械化学合成是大规模生产COF的有前途的潜在工具,它将更多地利用COF降解污染物。
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Ball Milling Synthesis of Covalent Organic Framework as a Highly Active Photocatalyst for Degradation of Organic Contaminants
Facile, environmentally-friendly fabrication of high-yield and stable covalent organic framework (COF) materials has been a limitation to their large-scale production and application. In this work, ball milling was used to synthesize COF by mechanochemical reaction between 1,3,5-triformylphloroglucinol (Tp) and melamine (MA) at ambient temperature. Different routes (liquid-free, solvent-assisted and catalyst-assisted) and proportions of liquids (solvents or catalyst) were investigated. Two morphologies were obtained when various amounts of liquid were added during grinding. The two forms were interwoven thread-shaped and exfoliative thin ribbon-like structures. Further, visible-light photocatalytic (λ > 400 nm) performance and mechanism of the two structures of COFs were investigated. The exfoliative ribbon-like structures exhibited greater rates of photodegradation of phenol and retained 87.6% of initial photodegradation after being used four times. Addition of liquid catalyst not only improved crystallinity of the COF materials, but also enhanced rates of photocatalytic reactions. Photocatalytic activity of the exfoliative structure of TpMA synthesized by ball milling was comparable with that of the photocatalyst prepared by use of the solvothermal method, while time to prepare the catalyst was shortened by 36-fold and the amount of solvent used was reduced by 8-fold at room temperature. Mechanochemical synthesis is a promising potential tool for large-scale production of COFs, which will make greater use of COFs for degradation of pollutants.