CeO_2-x platelet from monometallic cerium layered double hydroxides and its photocatalytic reduction of CO₂

Monometallic cerium layered double hydroxides (MCe-LDHs) were successfully synthesized for the first time through a simple approach. XRD, TEM, SEM, XPS, FT-IR, TG-DSC techniques and UV–vis diffuse reflectance spectroscopy were used to characterize the samples. The obtained MCe-LDHs showed typical layered structure composing of quasi-hexagonal platelets with side length of about 2 μm and thickness about tens of nanometers, and preserved its platelet morphology after heat treatment at up to 800 °C. Our study also revealed that the heat-treatments at different temperatures could be employed to tune the concentration ratio of Ce³⁺/Ce⁴⁺ and the surface area of those cerium oxide platelets, both of which play a key role in the photocatalytic activity towards photoreduction of CO₂.