Preparation Of Cu-based Semiconductor Catalysts And Performance For Degradation Of Environmental Pollutants

The novel straw sheaf-like CuO single crystals have been prepared through a facile two-step process: hydrothermal and subsequent calcination for the first time.We have mainly investigated the influences of the copper(II) concentration, the added amount of hexamethylenetetramine (HMT), reaction temperature and time on the samples. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy(HRTEM) and nitrogen sorption isotherms. The results show that the formed CuO straw sheaves are fairly uniform,and the single straw grows preferentially along the[001] orientation. It is proposed that the CuO straw sheaves were formed by a crystal splitting growth process. Furthermore, under visible-light irradiation, the CuO straw sheaves exhibit 5.3 times higher activity than the irregular sample for the degradation of rhodamine B (RhB), which has been ascribed to the exposed {110} facets and high crystallinity.Based on the splitting mechanism, One- and three-dimensional (1D, 3D)Cu(OH)PO4 hierarchical architectures have been successfully prepared by a facile hydrothermal method, mainly through adjusting the precursor concentrations.Besides, through experiments and density functional theory (DFT) calculations, we find that copper hydroxyphosphate (Cu(OH)PO4) shows an excellent catalytic activity for the degradation of rhodamine B (RhB). This has been mainly ascribed to the contribution of hydroxyl groups contained in Cu(OH)PO4, which favors to form more hydroxyl radicals. Moreover, both partial density of states (PDOS) and total density of states (TDOS) have confirmed that the conduction band (CB) is affected by part of the O 2p orbitals of the hydroxyls; thus the hydroxyl group is responsible for the increased band gap and the positive VB of Cu(OH)PO4. This study suggests that new photocatalysts or photoelectric materials can be developed via introducing hydroxyl groups.