Decoration of NH2-UiO-66 with FeOOH quantum dots for improving photo-degradation of organic dyes upon visible light irradiation

[Display omitted] •MOF materials such as NH2-UiO-66 was decorated for the first time with FeOOH QDs.•The prepared NH2-UiO-66/FeOOH QDs photocatalyst was used for water remediation.•Photo-Fenton activity of photocatalyst was found greater than individual MOF and QDs.•Transfer of photo-excited e- from MOF to FeOOH QDs resulted to charge separation.•Both h+ and •OH were responsible for efficient degradation of pollutants. Coupling of inexpensive and easily synthesized FeOOH quantum dots (QDs) with metal–organic frameworks (MOFs) is an outstanding subject in photocatalysis field, which no research works have been reported in this regard so far. For this purpose, a novel photocatalyst was prepared by in-situ formation of different amounts of FeOOH QDs (5, 10 and 15 wt%) in the presence of NH2-UiO-66 as visible light-harvesting MOF. HR-TEM analysis revealed uniform decoration of NH2-UiO-66 with 2–5 nm sized FeOOH QDs. Photo-Fenton behavior of the resulted NH2-UiO-66/FeOOH(10 %) composite in the degradation of methyl violet (MV) was found to be higher than other composites with different loadings of FeOOH QDs. The effect of H2O2 and photocatalyst dosage were also investigated and the best degradation efficiency of 82.2 % was achieved at optimal reaction conditions. It was observed that both FeOOH QDs and NH2-UiO-66 demonstrated poor photocatalytic activity individually, but their composite resulted in outstanding photo-Fenton activity because of effective electron transfer from photo-excited NH2-UiO-66 to FeOOH QDs. Scavenging experiments indicated that hydroxyl radicals and photo-generated hole are the main species responsible for photo-Fenton degradation of water contaminants.