Facile in-situ synthesis of floating CeO2@ expanded graphite composites with efficient adsorption and visible light photocatalytic degradation of phenol

Abstract A facile solution to obtain efficient, stable and cheap photocatalysts was conducted in this work. CeO2@ expanded graphite (CeO2/EG) composites were in-situ synthesized with a new strategy, in which CeCl3 molecules inserted the graphite intercalation compound (GIC) and converted into CeO2 as GIC changed into EG via instant calcination. The introduction of EG has accelerated the adsorption of contaminant molecules, promoted the charge transfer and improved the photocatalytic efficiency. The best sample, containing 80.75 wt% CeO2 particles of nanometer scale, has achieved the highest pollutant removal efficiency of 97.3% for phenol, displaying the highest reaction rate constant of 0.0262 min−1, which was 35.4 times higher than CeO2. Besides, it possesses good stability and keeps floating in water pollution treatment, showing great advantages to work in natural water body. Phenol and its degradation intermediates were identified using HPLC/MS, and appropriate reaction pathways were proposed.