Two-dimensional porous cuprous oxide nanoplatelets derived from metal–organic frameworks (MOFs) for efficient photocatalytic dye degradation under visible light

Abstract

Bottom-up synthesis is a promising method to design and control the morphology of metal–organic frameworks (MOFs). Here, square shaped two-dimensional (2D) MOF nanoplatelets with a thickness of ∼80 nm and a lateral dimension of 4–6 μm were successfully synthesized through a facile solvothermal treatment of Cu(NO₃)₂ and 4,4′-bipyridine in the presence of polyvinyl pyrrolidone (PVP). The growth of a cross-weaved structure assembled via 1D chains linked with 4,4′-bipyridine along the layer stacking direction was hindered by PVP, resulting in a high-aspect ratio of the nanoplatelets. Subsequent annealing treatment converted the Cu-based MOFs into porous N-doped Cu₂O/carbon composites, retaining the 2D square morphology. This annealed product showed a higher performance in the degradation of methyl orange under visible light compared to previously reported Cu₂O composites. By using a small amount of the catalyst, the degradation rate could reach up to 2.5 mg min⁻¹ g_cat⁻¹ as a result of the efficient absorption of visible light and high surface area of the porous catalysts.