The Photocatalytic Application of Semiconductor Stibnite Nanostructure Synthesized via a Simple Microwave-Assisted Approach in Propylene Glycol for Degradation of Dye Pollutants and its Optical Property

Facile hydrothermal synthesis of MXene@antimony nanoneedle composites for toxic pollutants removal

A new 2D transition metal carbides family noted that MXene with antimony (Sb) nano-needles composites have demonstrated potential applications for photocatalytic dye degradations applications. Single-step synthesis of novel structures two/one-dimensional MXene@antimony nanoneedle (MX@Sb-H) nanocomposite-based photocatalysts is produced employing hydrothermal technique. The preparations and characterizations were compared with hand mixture preparations of pure TiO₂@Sb and MXene (MX@Sb-M). The crystallographic structure was identified employing X-ray diffraction (XRD) studies and main sharp XRD peaks were observed with diffraction angle with orientations planes for all three samples TiO₂@Sb, MX@Sb-M and MX@Sb-H. The micro-Raman spectroscopy explored key vibration modes centered at 151.72 and 637.52 cm^-1 corresponding to Ti and Sb hybrid composites respectively. Fourier transform infrared spectroscopy (FTIR) spectrum of functional group peaks at 609.16 and 868.80 cm^-1 revealed Ti-OH/Sb-O-C stretching. The morphological investigations of horizontal growth for "Sb" nanoneedle on MXene nanosheets were explored by scanning electron microscopy (SEM). The degradation efficiency was calculated. The efficiency calculated were 27%, 38%, 68% and 82% for MB solution, TiO₂@Sb added MB, MX-Sb-M added MB and MX-Sb-H added MB solution and the efficiency were 32%, 38%, 50% and 65% for pure RhB solution, TiO₂@Sb added RhB, MX-Sb-M added RhB and MX-Sb-H added RhB solution. The photocatalytic activity of TiO₂@Sb, MX@Sb-M and MX@Sb-H was examined. Among these MX@Sb-H nanocomposite was demonstrated the high photocatalytic action in expressions of rate stability of photocatalytic dye degradations.

Selective and Recyclable Congo Red Dye Adsorption by Spherical Fe3O4 Nanoparticles Functionalized with 1,2,4,5-Benzenetetracarboxylic Acid

In this study, the new material Fe3O4@BTCA has been synthesized by immobilization of 1,2,4,5-Benzenetetracarboxylic acid (BTCA) on the surface of Fe3O4 NPs, obtained by co-precipitation of FeCl3.6H2O and FeCl2.4H2O in the basic conditions. Characterization by P-XRD, FE-SEM, and TEM confirm Fe3O4 has a spherical crystalline structure with an average diameter of 15 nm, which after functionalization with BTCA, increases to 20 nm. Functionalization also enhances the surface area and surface charge of the material, confirmed by BET and zeta potential analyses, respectively. The dye adsorption capacity of Fe3O4@BTCA has been investigated for three common dyes; Congo red (C.R), Methylene blue (M.B), and Crystal violet (C.V). The adsorption studies show that the material rapidly and selectively adsorbs C.R dye with very high adsorption capacity (630 mg/g), which is attributed to strong H-bonding ability of BTCA with C.R dye as indicated by adsorption mechanism study. The material also shows excellent recyclability without any considerable loss of adsorption capacity. Adsorption isotherm and kinetic studies suggest that the adsorption occurs by the Langmuir adsorption model following pseudo-second-order adsorption kinetics.

Wafer-Scale Fabrication of Sub-10 nm TiO2-Ga2O3 n-p Heterojunctions with Efficient Photocatalytic Activity by Atomic Layer Deposition

Wafer-scale, conformal, two-dimensional (2D) TiO₂-Ga₂O₃ n-p heterostructures with a thickness of less than 10 nm were fabricated on the Si/SiO₂ substrates by the atomic layer deposition (ALD) technique for the first time with subsequent post-deposition annealing at a temperature of 250 °C. The best deposition parameters were established. The structure and morphology of 2D TiO₂-Ga₂O₃ n-p heterostructures were characterized by the scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), etc. 2D TiO₂-Ga₂O₃ n-p heterostructures demonstrated efficient photocatalytic activity towards methyl orange (MO) degradation at the UV light (λ = 254 nm) irradiation. The improvement of TiO₂-Ga₂O₃ n-p heterostructure capabilities is due to the development of the defects on Ga₂O₃-TiO₂ interface, which were able to trap electrons faster.

Effect of Zinc Acetate Concentration on Optimization of Photocatalytic Activity of p-Co3O4/n-ZnO Heterostructures

In this work, p-Co₃O₄/n-ZnO heterostructures were fabricated on Ni substrate by hydrothermal-decomposition method using cobaltous nitrate hexahydrate (Co(NO₃)₂·6H₂O) and zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O) as precursors with zinc acetate concentration varying from 5.0 to 55.0 mM. Structure and morphology of the developed samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Effect of zinc acetate concentration on the photocatalytic activity of p-Co₃O₄/n-ZnO heterostructures was investigated by degradation of methyl orange (MO) under the UV light irradiation. The fabricated p-Co₃O₄/n-ZnO heterostructures exhibited higher photocatalytic activity than pure Co₃O₄ particles. In order to obtain the maximum photocatalytic activity, zinc acetate concentration was optimized. Specifically, at 35 mM of zinc acetate, the p-Co₃O₄/n-ZnO showed the highest photocatalytic activity with the degradation efficiency of MO reaching 89.38% after 72 h irradiation. The improvement of photocatalytic performance of p-Co₃O₄/n-ZnO heterostructures is due to the increased concentration of photo-generated holes on Co₃O₄ surface and the higher surface-to-volume ratio in the hierarchical structure formed by nano-lamellas.