Structural, optical, and magnetic properties of Cu‐doped TiO₂ samples

Abstract

We report here the microstructure, optical, and magnetic properties of Cu-doped TiO 2 (Ti 1−x Cu x O 2 ) nanopowder samples with x = 0.02, 0.04, and 0.06 prepared by a solid-state reaction method. XRD studies indicated the incorporation of Cu into the TiO 2 lattice. Ultraviolet-visible spectroscopy (UV-vis) measurements revealed that the band gap decreased due to the incorporation of Cu. Photoluminescence (PL) results showed an enhanced photoluminescence property associated with oxygen vacancies from TiO 2 due to the incorporation of Cu. Magnetic investigations demonstrated that all of the samples had room temperature ferromagnetism (RTFM). RTFM was observed in the Ti 0.98 Cu 0.02 O 2 samples annealed at 500°C and reduced RTFM was clearly observed in the samples annealed at high temperatures of 600 and 700°C. Furthermore, the saturation magnetic moment decreased with increasing Cu content for the samples annealed at 500ᴼC with different doping Cu contents, due to the increased Cu atoms occupying neighbouring cation lattice sites, which resulted in an antiferromagnetic configuration. The results demonstrated that defects and/or oxygen vacancies, and the distances between nearest-neighbour Cu atoms, have a significant influence on ferromagnetism in Cu-doped TiO 2 powder samples.

Single-atom Cu anchored catalysts for photocatalytic renewable H2 production with a quantum efficiency of 56%

“…In addition, the photocurrent response of CuSA-TiO 2 shows high reproducibility and stability for several on/off cycles. Moreover, the electrochemical impedance spectra (EIS) were used to study the transfer properties of charge carriers 46 , as indicated in Supplementary Fig. 16b .…”

Highly enhanced photocatalytic hydrogen evolution activity by modifying the surface of TiO2 nanoparticles with a high proportion of single Cu atoms

“…The EIS spectra were used to study the transfer properties of charge carriers, 26 as indicated in Fig. 5(c).…”

Color stability of blue aluminates obtained from recycling and applied as pigments

“…Aluminates have been widely used as dyes and pigments due to their structural arrangement in the spinel form (A 2+ B 2 3+ O 4 2− ) that allows the insertion of chromophore ions, which guarantee intense color and high thermal stability, in addition to resistance to chemically aggressive environments. 15,16 The synthetic routes most used to obtain aluminates are coprecipitation, 17 mixed oxide calcination, 18 solid-state reactions, 19 and the sol–gel method. 20 In addition, there is the possibility of recycling aluminum to be used as a pigment precursor, 17 providing a more sustainable synthesis compatible with the circular economy concept, which is based on reducing, repairing, recycling, remanufacturing, and redirecting the materials life cycle, 21,22 contributing to the production of more sustainable materials.…”