CdMoO4 Micro-ellipsoids: Controllable Synthesis, Growth Mechanism, and Photocatalytic Activity

Abstract

CdMoO 4 micro-ellipsoids were synthesized by a simple hydrothermal route with the assistance of nonionic surfactant Triton X-100 and characterized by X-ray diffraction, scanning electron microscopy and UV-Vis diffuse reflectance spectroscopy. The effects of hydrothermal pH, temperature, and time on the morphology and photocatalytic activity of CdMoO 4 were investigated. With an initial hydrothermal pH of 5.00, CdMoO 4 micro-ellipsoids were obtained at 180 °C for 24 h and found to possess the highest photocatalytic activity-89% Rhodamine B can be degraded for 30 minutes presented in the 0.4 g/L CdMoO 4 suspension. The formation mechanism of the CdMoO 4 micro-ellipsoids was initiated by the formation of small nanoparticles and bulk structures afterwards, which was followed by the growth of micro-ellipsoids. Experiment results showed that the evolution of the micro-ellipsoids was an Ostwald ripening process.

Assessment of Lewis‐Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

“…[ 20 , 21 ] On the other hand, the XRD pattern of CdO clearly displayed five very strong diffraction peaks at 2θ=33.07° (111), 38.34° (200), 55.30° (220), 65.96° (311) and 69.26° (222) which belong to face‐centred system (Monteponite CdO, JCPDS # 5‐0640) as shown in Figure 1 e.[ 22 , 23 ] Three distinct diffraction peaks can be observed in patterns b‐d of mixed MoO 3 ‐CdO samples at 2θ=29.25° (112), 31.99° (004) and 34.38° (200), which could be related to the formation of tetragonal phase CdMoO 4 in these mixtures (JCPDS # 07–0209). [ 24 , 25 , 26 ] The crystallite size of the obtained different phases in these samples, that is, α‐MoO 3 , CdO and CdMoO 4 , was calculated using the Scherrer equation. [22] For MoO 3 in all patterns a‐d, the full width at half maximum (FWHM) of the narrow Debye–Scherrer line at 2θ=27.30° was used to calculate the crystallite size of MoO 3 , revealing a size range of 65–80 nm.…”

“…[22,23] Three distinct diffraction peaks can be observed in patterns b-d of mixed MoO 3 -CdO samples at 2θ = 29.25°(112), 31.99°(004) and 34.38°( 200), which could be related to the formation of tetragonal phase CdMoO 4 in these mixtures (JCPDS # 07-0209). [24][25][26] The crystallite size of the obtained different phases in these samples, that is, α-MoO 3 , CdO and CdMoO 4 , was calculated using the Scherrer equation. [22] For MoO 3 in all patterns a-d, the full width at half maximum (FWHM) of the narrow Debye-Scherrer line at 2θ = 27.30°was used to calculate the crystallite size of MoO 3 , revealing a size range of 65-80 nm.…”