A combined FTIR and infrared emission spectroscopy investigation of layered double hydroxide as an effective electron donor

• Electron could transfer from layer to interlayer anion both through monodentate and multidentate ligand in LDH structure.
• The electron transfer resulted in the reduction of interlayer anion.
• FTIR could characterize the transfer by monitoring the valence state of layer cation.
• Driving force for transfer is attributed to the charge density difference between cation layer and anion interlayer.

A novel method has been presented to characterize electron transfer in layered double hydroxides (LDHs) utilizing an investigation combing FTIR and infrared emission spectroscopy. At room temperature, electron could transfer to interlayer Fe3 + through monodentate ligand cyanide, and resulted in a reduction of 40% Fe3 + to Fe2 +. When the environmental temperature increased from 25 to 300 °C, reduction of Fe3 + and Ni2 + increased to 94% and 42%. Furthermore, electron also transferred to interlayer cation through multidentate ligand EDTA. As a result, LDHs has been proven to be an effective electron donor, and FTIR was a feasible tool in characterizing this property by monitoring the valence state of cations. It was also concluded that octahedral units with OH− groups in LDH layer functioned as electron donor centers. Driving force for electron transfer is attributed to the charge density difference between cation layer and probe anion. These results could help to explain the mechanism of various applications of LDHs in catalysis and photocatalysis.

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