Preparation of RGO-MIL-68(Fe) composites by a simple self-assembly strategy for photocatalytic reduction of Cr(Ⅵ)
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摘要: 采用静电自组装方法制备氧化石墨烯(GO)-MIL-68(Fe)复合物,并通过简单溶剂热处理,将GO还原为还原氧化石墨烯(RGO),首次制得RGO-MIL-68(Fe)复合物。通过XRD、FESEM、紫外-可见漫反射光谱(UV-Vis DRS)等方法对RGO-MIL-68(Fe)复合催化剂的晶体结构、形貌、光吸收性能等物理化学性质进行表征。在可见光照射下,以草酸铵((NH4)2C2O4)为牺牲剂,对RGO-MIL-68(Fe)复合材料进行光催化还原Cr(Ⅵ)性能评价,结果表明,只需复合少量的RGO,MIL-68(Fe)的光催化活性就能显著地提高。当RGO含量为1wt%时,RGO-MIL-68(Fe)复合材料表现出最优的光催化活性,反应60 min,体系中的Cr(Ⅵ)的还原率高达81%。结合电化学分析可知,这主要是由于RGO的引入在增强MIL-68(Fe)光吸收性能的同时也促进了光生载流子的分离。
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关键词:
- 静电自组装 /
- MIL-68(Fe) /
- 还原氧化石墨烯(RGO)-MIL-68(Fe)复合物 /
- 光催化 /
- Cr (Ⅵ)
Abstract: Novel photocatalysts reduced graphene oxide (RGO)-MIL-68(Fe) were synthesized via an electrostatically derived self-assembly of MIL-68(Fe) with graphene, followed by solvothermal approach. The as-prepared RGO-MIL-68(Fe) composites were characterized by XRD, FESEM and UV-vis diffuse reflectance spectra (UV-vis DRS). The photocatalytic activity for reduction of Cr(Ⅵ) over RGO-MIL-68(Fe) composites were investigated under visible light irradiations using ammonium oxalate ((NH4)2C2O4) as a sac-rificial agent. The results show that the reduction of Cr(Ⅵ) over MIL-68(Fe) can be significantly increased by loading RGO. An optimum activity is achieved over 1wt%RGO-MIL-68(Fe) composite, giving a corresponding Cr(Ⅵ) reduction ratio of 81% after 60 min under visible light irradiation. Combining with photoelectrochemical analyses, it can be revealed that the introduction of RGO will minimize the recombination of photogenerated electron-hole pairs.-
Key words:
- self-assembly /
- MIL-68(Fe) /
- reduced graphene oxide (RGO)-MIL-68(Fe) composite /
- photocatalysis /
- Cr(Ⅵ)
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