Enhancing the Photocatalytic Performance of BaSn-based Composites by Doping Rare Metals

Abstract

Rare metal (La or Nd) doped BaSn-based composites with highly polycrystalline nature were successfully synthesized through a simple hydrothermal route.The doped composites were investigated by X-ray diffraction, electron microscopy, solid ultraviolet diffuse reflectance spectrum, X-ray photoelectron spectroscopy, photoluminescence, electrochemical impedance spectroscopy, and photocatalytic measurements. La and Nd doping induces the morphological change of the BaSn-based composites from the nanorods to irregular nanoscale particles with the average size of about 100 nm. La and Nd in the doped composites exist in the form of cubic La 2 Sn 2 O 7 and cubic Nd 2 Sn 2 O 7 phases. The absorption edge of the doped composites red-shifts comparing with that of the non-doped composites. The doped BaSn-based composites with the La or Nd mass ratio of 8 wt% possess the smallest band-gap energy in the doped composites and the good light absorption ability. The La or Nd doping mass ratio has an important role in the photocatalytic degradation of the crystal violet (CV) dye. The CV molecules in the 20-mL CV solution with 10 mg L −1 can be totally removed by the 20-mg La-or Nd-doped BaSn-based composites under the light irradiation for 150 min. Scavenger experiments show that hydroxyl free radicals (•OH) and superoxide anion radicals (•O 2 − ) are effective oxidizing agents for CV degradation. Photoluminescence and electrochemical impedance spectroscopy show that the significant decrease in the recombination ability of the electron and hole pairs by the rare metal doping is of great importance for enhancing the photocatalytic activity of the BaSn-based composites. The La-or Nd-doped BaSn-based composites show good reusability for CV degradation. Keywords BaSn-based composites; Rare metal; Doping; Crystal violet; Photocatalysis 42 et al. [9] reported that the tin oxide nanospheres had large 43 specific surface area with the value of about 160 m 2 g −1 and 44 exhibited good photocatalytic activity towards methyl or-45 ange (MO) under the ultraviolet (UV) light with good pho-46 tocatalytic recyclability. Very recently, BaSn-based nanorods 47 with monoclinic BaSn(OH) 6 and orthorhombic SnO 2 phases, 48 50−150 nm in diameter, were successfully prepared by our 49 group [10]. The obtained BaSn-based nanorods possessed a 50 band-gap energy of 3.74 eV and showed good photocatalytic 51 activity towards crystal violet (CV) under the UV light irra-52 diation. However, the band-gap energy of the BaSn-based 53 nanorods is large and is restrictive for the application in the 54 photocatalytic field. Therefore, it is essential to develop ef-55 ficient method to decrease the band-gap energy and to en-56 hance the photocatalytic properties of the BaSn-based na-firstly investigated by analyzing the relationship between the 359 CV concentration change ratio (C/C 0 ) and the UV light irra-360 diation time. The CV degradation efficiency was calculated 361 according to the following equation: CV degradation effi-362 ciency % = (1 − C/C 0 ) × 100, where ...

Dynamic Reconfiguration and Local Polarization of NiFe‐Layered Double Hydroxide‐Bi2MoO6−x Heterojunction for Enhancing Piezo‐Photocatalytic Nitrogen Oxidation to Nitric Acid

“…[ 34,35 ] Those peaks located at 352 and 401 cm −1 , 709, 789, and 841 cm −1 , which belong to the E u symmetric bending and stretching modes of MoO 6 octahedrons. [ 36,37 ] Moreover, the peaks at 321, 460, and 534 cm −1 are related to the O‐H, Ni‐O, and Fe‐O vibrations in LDH, respectively. [ 38,39 ] Notably, compared with BMO, NF, and BBNF, the lattice mode of Bi‐O bonds in the BNF‐4 shifted to the lower wavenumber, and the intensity was increased, suggesting the amount and bond length of the Bi‐O bonds are increased.…”