Low-Temperature Decarboxylation and Sensitive Detection of Trifluoroacetic Acid on the Interface of Active Amino Nickel Metal Organic Layers

Trifluoroacetic acid (TFA), a common end degradation product of perfluorinated compounds (PFCs), presents a grave hazard to human health. Consequently, there is an imperative to construct novel methods of TFA degradation and sensing. Here, a TFA-amino-nickel metal–organic layer (NH₂–Ni-MOLs) gas–solid interface reaction system was established. The gas–solid interface reaction was investigated in detail using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), theoretical calculations and XPS depth profiling. It was demonstrated that TFA anchored to the surface of NH₂–Ni-MOLs at 40 °C by interactions of ligand with Ni²⁺. And then, the small molecules of fluoride produced by the continuous decarboxylation reaction of TFA adsorbed by NH₂–Ni-MOLs, which ultimately formed the fluorine-containing small molecule nanointerface layer ultimately. Notably, the XPS integral area gradually increases with the concentration of fluorinated small molecules in the interfacial layer, and a novel strategy for the sensitive detection of TFA was developed. In summary, based on the NH₂–Ni-MOLs-TFA gas–solid interface, efficient decarboxylation reaction of TFA at low temperature and the sensitive detection of TFA by XPS were achieved, which will open a unique avenue for the degradation and sensitive detection of PFCs.