Since the exciting discovery that binding of 4-ethynylaniline on the inert Cu2O cubes makes the functionalized cubes highly photocatalytically active toward methyl orange (MO) degradation, binding of 2-ethynyl-6-methoxynaphthalene (2E-6MN) molecules...

The inert Cu2O cubes exhibit a superior photocatalytic activity after functionalized with 4-nitrophenylacetylene (4-NA). The 4-NA-modifed Cu2O octahedra and rhombic dodecahedra also show significant activity enhancement. Infrared and X-ray photoelectron...

Semiconductor crystals have generally shown facet‐dependent electrical, photocatalytic, and optical properties. These phenomena have been proposed to result from the presence of a surface layer with bond‐level deviations. To provide experimental evidence of this structural feature, synchrotron X‐ray sources are used to obtain X‐ray diffraction (XRD) patterns of polyhedral cuprous oxide crystals. Cu2O rhombic dodecahedra display two distinct cell constants from peak splitting. Peak disappearance during slow Cu2O reduction to Cu with ammonia borane differentiates bulk and surface layer lattices. Cubes and octahedra also show two peak components, while diffraction peaks of cuboctahedra are comprised of three components. Temperature‐varying lattice changes in the bulk and surface regions also show shape dependence. From transmission electron microscopy (TEM) images, slight plane spacing deviations in surface and inner crystal regions are measured. Image processing provides visualization of the surface layer with depths of about 1.5–4 nm giving dashed lattice points instead of dots from atomic position deviations. Close TEM examination reveals considerable variation in lattice spot size and shape for different particle morphologies, explaining why facet‐dependent properties are emerged. Raman spectrum reflects the large bulk and surface lattice difference in rhombic dodecahedra. Surface lattice difference can change the particle bandgap.

Surface 4-cyanophenylacetylene (4-CNA) functionalization turned inert Cu2O cubes to possess a high photocatalytic activity. The modified rhombic dodecahedra also exhibited large activity enhancement, but decorated octahedra showed only moderate activity...