Mn-doped Zn/Al layered double hydroxides as photocatalysts for the 4-chlorophenol photodegradation

• Zn/Al layered double hydroxides doped with Mn 1% molar preserves the structure
• Mn as dopant in LDH increase the light absorption capacity in UV region
• Mn4 +, Mn3 + and Mn2 + can act as trap of holes or electron to separate the charge
• 4-Chlorophenol degradation is achieved with Mn-doped ZnAl layered structure
• Combined effect among OH and photogenerated holes increase the photoactivity

Mn-doped Zn/Al layered double hydroxides (LDH) with Mn 0.5–3.0% mol respect to Zn content with improved photocatalytic degradation of 4-chlorophenol (4Clphenol) were studied. The characterization studies showed the isomorphic incorporation Mn as dopant until 1% mol. The 4Clphenol degradation was proposed as result of a combined effect of oxidation by both hydroxyl radicals (OH) and photogenerated holes (h+). In a proposed mechanism it is suggested that Mn enhances the charge separation acting as electron e− (Mn3 +; Mn4 +) or hole h+ (Mn2 +; Mn3 +) traps according to its oxidation state. Exhaustive characterization through EDS, XRD, UV–vis-DRS, TEM-Dark field STEM, fluorescence spectroscopy for OH detection and XPS, has been done denoting the importance of the Mn content and its different oxidation states in the photophysical and photocatalytic properties of the Mn-doped Zn/Al-based layered double hydroxides.

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