Synthesis and characterization of the semiconductor CuBi2O4 for optical and dielectric studies. Application to methyl violet degradation under visible light

Abstract

This work is devoted to the synthesis, optical and dielectric properties of CuBi 2 O 4 prepared by sol-gel route. The X-ray diffraction analysis shows that CuBi 2 O 4 crystallizes in a tetragonal symmetry (SG: P4/cnn) with lattice parameters: a = 8.5023 Å and c = 5.8250 Å; the Rietveld refinement reveals a high purity of the spinel. The crystallite size (D = 47.84 nm) was calculated from the Williamson Hall-plot. The presence of Cu-O and Bi-O bonds with Cu 2+ tetrahedrally coordinated is confirmed by the Raman spectroscopy. We also report the optical and dielectric properties of CuBi 2 O 4 , including the refractive index (n λ ), optical (σ opt ) and electrical (σ ele ) conductivities, extinction coefficient (k λ ), dissipation factor (tan δ) and relaxation time (τ). The forbidden band (E g ), measured from the UV-Visible diffuse reflectance spectroscopy, is found in the range (1.50-1.55 eV) and confirmed by these approaches. Furthermore, the as-prepared compound has been successfully tested for the first time for the methyl violet degradation under visible light. The results show a conversion rate of 75% under illumination of 4 h 30 min and that the kinetics follows a first order model.

Enhanced Hydrogen Evolution Reaction Performances of Ultrathin CuBi2O4 Nanoflakes

“…Figure 2 102), (002), (310), (112), (202), (400), (330), (312), (411), (420), ( 213), (332), (521), (004), (413), (204), (532), (541), (602), and (622) planes of tetragonal CuBi 2 O 4 (JCPDS file no. , respectively [18,36,40,51]. The absence of other secondary phases depicts that the synthesized CuBi 2 O 4 samples possess a single phase of tetragonal CuBi 2 O 4 .…”

“…Furthermore, the small band-gap energy (1.5-1.8 eV) and the high physicochemical stability of CuBi 2 O 4 allow us to use it in high-performance electrocatalytic water splitting [25][26][27][28]. With regard to the synthesis of the CuBi 2 O 4 nanostructure, there are a lot of experimental methods, for instance, solvothermal [21,29], combustion [30], coprecipitation [31][32][33], sonochemical [34,35], hydrothermal [22,36,37], solution process [26], drop casting [38], sputtering [39], sol-gel [40], and polymerization [19]. Among these, the coprecipitation method is one of the prominent fabrication techniques because of its facileness, swiftness, cost-effectiveness, and high compatibility for mass production [41].…”

An ab initio DFT perspective on experimentally synthesized CuBi2O4

“…The CBO has the potential as a photocatalytic dye degrading material. 30,109,110 We performed photocatalytic measurements to estimate the HCBO's MB dye annihilation capabilities under simulated solar exposure. The MB solution absorption in the visible range of the electromagnetic spectrum is measured for two different pH values (5 and 10) to demonstrate the photocatalytic degradation as shown in Fig.…”

“…18,[23][24][25][26][27] The sol-gel methods produced CBO with a lower solution temperature of ∼200 °C followed by subsequent thermal annealing at elevated temperatures (∼600-800 °C). [28][29][30] The dendritic CBO nanoparticles were obtained at low-temperature (below ∼100 °C) from a solution chemistry approach. 31 The hydrothermal approach yield phase pure CBO at temperatures below 180 °C with varying morphology.…”