Synthesis of Visible-Light-Responsive Cu and N-Codoped AC/TiO2 Photocatalyst Through Microwave Irradiation

Abstract

N–Cu-activated carbon (AC)/TiO2 nanoparticles were prepared by the sol-gel technique through microwave irradiation to modify the visible-light response of TiO2. Their structure, surface chemical composition, and optical absorption properties were characterized. The results showed that the codoped particles had a higher surface area and smaller particle size than pure AC/TiO2 and monodoped AC/TiO2. X-ray photoelectron spectroscopy of N–Cu-AC/TiO2 showed that Cu atoms replaced Ti atom sites, whereas N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice, which changed the electric and band-gap structures of the photocatalyst. N or Cu monodoping of AC/TiO2 reduced the energy band gap of TiO2 from 2.86 eV to 2.81 or 2.61 eV, respectively. In (N, Cu)-codoped AC/TiO2, N and Cu were incorporated into the TiO2 framework and narrowed the band gap of TiO2 to 2.47 eV, causing a large red shift and enhancing visible-light utilization efficiency. Photocatalytic activities were further examined by formaldehyde degradation under visible-light irradiation. N–Cu-AC/TiO2 was found to have the highest activity (ca. 94.4 % formaldehyde degradation efficiency) and to be easily recyclable. These results show an important and innovative method of improving AC/TiO2 activity by modifying the nonmetallic and metallic species.

Retracted: The Fabrication of Magnetically Recyclable La-Doped TiO2/Calcium Ferrite/Diatomite Composite for Visible-Light-Driven Degradation of Antibiotic and Disinfection of Bacteria

“…Figure 4b shows the spectrum of Ti ion, and its two peaks that located at 464.3 and 458.4 eV are attributed to Ti 2p 1/2 and Ti 2p 3/2 , respectively. This result implies that Ti exists as Ti 4+ from anatase-phase TiO 2 (Tian et al, 2016). Figure 4c shows the Ca 2p XPS spectrum.…”

Retracted: Self‐floating Cu/N co‐doped TiO2/diatomite granule composite with enhanced visible‐light‐responsive photoactivity and reusability

“…This result might be ascribed to the segregation of Cu-dopants which formed Cu-O-Ti bonds with TiO 2 and hindered the grain growth by blocking direct contact of TiO 2 grains. 11 Besides, the crystal size of TiO 2 in N-TDHG is smaller than that in TDHG, implying that the N-dopant also showed similar hindering effect. This might be explained by the fact that, when N-dopant was introduced to the TiO 2 lattice via the wet method (sol-gel method or hydrolysis method), it located at the interstitial sites and inhibited the crystal growth of TiO 2 grains.…”

“…This result is in accordance with other results in the literature, that is, the dopant Cu 2+ ion might have been transformed to Cu + and thus acted as electron acceptor, inhibiting the recombination of photo-induced electron and hole, leading to the improvement of photoactivity. 27 However, when the doping amount of Cu surpassed a certain value, its role changed to recombination center for both radicals, 11 which resulted in the decrease of photoactivity. In this work, this value was determined to be the doping percentage in CN-TDHG-2.…”

The structure and self-regeneration performance of Salix psammophila-activated carbon modified by Ag and N co-doped TiO2

“…Wu et al found that the photocatalytic activities of monodoped TiO 2 -AC were signicantly improved by N/La co-doping and N/Cu co-doping, respectively. 17,18 However, few studies have focused on the study of AC modied with Ag and N co-doped TiO 2 (Ag-N-TiO 2 ).…”