Metal–Organic Framework-Ag Nanocomposites as Photocatalysts and in Situ Surface-Enhanced Raman Spectroscopy Sensors to Study the Mechanisms of CO₂ Reduction Reactions

Abstract

Nanocomposites could combine the advantages of various materials, allowing them to be used to achieve special applications that cannot be achieved with a single material. Here, nanocomposites composed of plasmonic nanocrystal (silver nanocube, AgNC) and metal−organic frameworks (ZIF-8 or metal−organic framework (MOF)-801) had the advantages of excellent surface-enhanced Raman spectroscopy (SERS) performance and high CO 2 reduction activity of AgNC and excellent CO 2 capture performance of MOFs, which enabled these nanocomposites to be used as an in situ SERS sensor to detect CO 2 reduction. The results showed that the CO 2 adsorption performance of MOF-AgNC nanocomposites strongly depended on the thickness of the MOF shell and the internal environment of the MOF, and these nanocomposites as CO 2 reduction photocatalysts can produce different products, which were strongly dependent on the environment of the MOF-AgNC interface. The ratedetermining step of CO 2 reduction in different MOF-AgNC nanocomposite systems also exhibited differences, which can be attributed to the different MOF and CO 2 interactions. These results demonstrated that MOF-AgNC nanocomposites are feasible as an in situ SERS sensor for observing CO 2 reduction, which makes it possible to design different nanocomposites as suitable in situ Raman spectroscopy sensors to detect various chemical reactions.