Controllable Synthesis of Cu 2 O Microcrystals via a Complexant‐Assisted Synthetic Route

A novel method using Cu(AC) 2 · H 2 O and dimethylglyoxime as reagents has been successfully developed for the controllable synthesis of Cu 2 O microcrystals with distinctive morphologies, including porous hollow microspheres, octahedral microcages, and microcrystals with truncated corners and edges and octahedral microcrystals. These structures can be fine‐tuned by varying reaction temperature, reaction time, and concentration. The products were characterized by X‐ray diffraction, field emission scanning electron microscopy, X‐ray photoelectron spectra, and UV/Vis diffuse reflectance spectra. This is the first report of the preparation of the novel microcage structure of Cu 2 O through a simple solution‐based route. By investigating the intermediate products which resemble the final crystal structures, a possible growth mechanism is proposed. Moreover, the investigations showed that the various 3D architectures of the as‐made products exhibit different abilities to catalytically degrade rhodamine‐B. Our work shows that octahedral Cu 2 O crystals with entirely {111} faces are photocatalytically more active than octahedral microcrystals with truncated corners and edges, suggesting the {111} faces of Cu 2 O nanostructures are catalytically more active than the {100} and {110} faces. Due to dual effect of the cavity structure and the {111} surfaces, the octahedral microcages with truncated corners and edges exhibit a higher extent of the photodecomposition reaction. As a result of very slow photocorrosion rate of the Cu 2 O microcrystal, it is expected that these microcrystals with different surfaces may find more applications in photocatalysis.