Enhanced visible light photocatalytic activity of Gd-doped BiFeO3 nanoparticles and mechanism insight

Abstract

To investigate the effect of Gd doping on photocatalytic activity of BiFeO3 (BFO), Gd-doped BFO nanoparticles containing different Gd doping contents (Bi(1−x)GdxFeO3, x = 0.00, 0.01, 0.03, 0.05) were synthesized using a facile sol-gel route. The obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, and ultraviolet-visible diffuse reflectance spectroscopy, and their photocatalytic activities were evaluated by photocatalytic decomposition of Rhodamine B in aqueous solution under visible light irradiation. It was found that the Gd doping content could significantly affect the photocatalytic activity of as-prepared Gd-doped BFO, and the photocatalytic activity increased with increasing the Gd doping content up to the optimal value and then decreased with further enhancing Gd doping content. To elucidate the enhanced photocatalytic mechanism of Gd-doped BFO, the trapping experiments, photoluminescence, photocurrent and electrochemical impedance measurements were performed. On the basis of these experimental results, the enhanced photocatalytic activities of Gd-doped BFO could be ascribed to the increased optical absorption, the efficient separation and migration of photogenerated charge carriers as well as the decreased recombination probability of electron-hole pairs derived from the Gd doping effect. Meanwhile, the possible photocatalytic mechanism of Gd-doped BFO was critically discussed.

Composites of Laminar Nanostructured ZnO and VOx-Nanotubes Hybrid as Visible Light Active Photocatalysts

“…It can be seen that the photodegradation efficiency of MB with the addition of isopropanol (a hydroxyl radical ( • OH) scavenger, 2 mM) and chloroform (a superoxide radical (O2 •− ) scavenger, 2 mM) was slightly decreased compared to those without the addition of quenchers. The addition of ammonium oxalate (a hole scavenger, 2 mM) did not show changes in the MB photodegradation activity [27,28]. The result of the scavenging test with chloroform and isopropanol are as seen, the removal efficiency of MB within 140 min of reaction time was decreased from 62.3% in the in the absence of the scavenger to 52.7% and 44.0%, respectively.…”

“…The addition of ammonium oxalate (a hole scavenger, 2 mM) did not show changes in the MB photodegradation activity [27,28]. The result of the scavenging test with chloroform and isopropanol are as seen, the removal efficiency of MB within 140 min of reaction time was decreased from 62.3% in the in the absence of the scavenger to 52.7% and 44.0%, respectively.…”

Enhanced Photocatalytic Activity and Biosensing of Gadolinium Substituted BiFeO3 Nanoparticles

“…In order to improve the photocatalytic activity and to avoid the recombination of e − /h + pairs in BF, some parameters have studied. Among them one is substituting of rare earth metal ions in the site of Bi which could enhance the photocatalytic activity by the formation of Fermi energy levels just below the conduction band and prevent the recombination of e − /h + pairs . Figure (a) and (b) shows the photocatalytic degradation of IC and CR as a function of irradiation time in the presence of synthesized samples.…”

Improved photocatalytic activity of Bi4TaO8Cl by Gd3+ doping

“…Furthermore, it is known that lanthanide ion doping in a photocatalyst can enhance its photocatalytic activity since the doped lanthanide ions acting as the electron or hole trappers lead to the formation and separation of e − –h + pairs during photocatalysis process . Among lanthanide ions, Gd 3+ is recommended as an effective ion for the improvement of photocatalytic activity because it can accelerate the electron transfer rate in the interfacial . To the best of our knowledge, we cannot find the report of Gd 3+ doping on the photocatalytic activity of Bi 4 TaO 8 Cl.…”

“…And in recent years, Bi 4 TaO 8 Cl with the layer structure of [Bi 2 O 2 ][TaO]–[Bi 2 O 2 ][Cl] has been reported as a promising photocatalyst due to the sunlight‐photocatalysis of dye degradation and water splitting . Furthermore, it is known that lanthanide ion doping in a photocatalyst can enhance its photocatalytic activity since the doped lanthanide ions acting as the electron or hole trappers lead to the formation and separation of e − –h + pairs during photocatalysis process . Among lanthanide ions, Gd 3+ is recommended as an effective ion for the improvement of photocatalytic activity because it can accelerate the electron transfer rate in the interfacial .…”