Crystal facet and surface defect engineered low dimensional CeO₂ (0D, 1D, 2D) based photocatalytic materials towards energy generation and pollution abatement

Surface defect engineering and crystal facet engineering are two important strategies which effectively enhance the efficiency of a photocatalyst by modulating its physiochemical properties. To date, surface defect and morphology dependent photoactivity has been explored by using different nanostructured photocatalysts. Among them CeO2 based materials have recently received foremost interest, due to their easily tunable surface structure and low formation energy for surface defects. Therefore, in this review we have comprehensively summarized the recent achievements and progress in surface defect enriched low dimensional nanostructured CeO2 and CeO2 based heterostructure photocatalysts towards clean fuel generation reactions such as water splitting, CO2 reduction, N2 fixation and organic/inorganic environmental pollutant removal applications. The present review highlights the design of CeO2 with particular crystal facets and morphology and the positive impact of the crystal facets on the construction of different CeO2 based heterostructure materials (0D–2D, 0D–1D, 1D–2D, 2D–2D, 0D–3D, etc.) with other low dimensional photocatalysts. Next, the surface defects, crystal facets and heterojunctional interfaces responsible for improved photoactivity are briefly discussed with proper experimental evidence and the mechanism along with the theoretical concept is explained. Further, this review sheds light on the current challenges and future perspectives in this research area.