Vietnam Journal of Catalysis and Adsorption

Methodology for synthesizing of β- and δ-carboline via two steps reaction from 2,3-dibromopyridine and 3,4-dibromopyridine. The intermediate was prepared from the substrate with o-bromophenylboronic acid via site-selective Suzuki-Myaura reaction, then, the final products were obtained by double C-N coupling via the Ulmann reaction of the intermediate with the corresponding amine with copper catalyst.

In the present work, results synthesis of  Fe-MIL-101 material and evaluation of photocatytic activity under visible light. Characterization of Fe-MIL-101 was investigated by using techniques including X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), IR spectra and UV-visible absorption spectrometer. Evaluation of the photocatalytic activity of Fe-MIL-101 material on the conversion of blue methylen solution under lighting and sunlight conditions.

In the present work, 3A zeolite was formed via a process of exchanging sodium by potassium in 4A zeolite. The 3A zeolite was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence (XRF). The chemical composition of the obtained product was 0,60K2O.0,39Na2O.Al2O3.2,02SiO2 with high crystalline. Its particles were completed with a uniform size in the range of 3 to 5 micrometer. Moreover, Cu(II) adsorption ability from aqueous solution onto 3A zeolite was investigated. With adsorbent’s dosage of 2,0 g.L-1 and at suitable pH of 4 to 5, more than 75 % of Cu(II) was removed from an aqueous solution that contained 40 mg Cu(II).L-1. Adsorption isotherm study confirmed that the Langmuir model well described the experimental data, and maximum adsorption capacity was about 33,1 mg.g-1.

In the present work, Fe-MIL101 formed by hydrothermal synthesis with ligand of H2BDC was characterized by physico-chemical mehods including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and N2 adsorption-desorption isotherm (BET). The results showed that the obtained material exhibited rather good crystallization, uniform crystals’ size and high BET surface area (736 m2.g-1). Phenol adsorption ability in aqueous solution onto Fe-MIL101 material was investigated. With adsorbent’s dosage of 4 g/L-1 and at suitable pH of 6-8, 55 % of phenol was removed from aqueous solution containing 20 mg phenol.L-1. Adsorption isotherm study confirmed Langmuir model well described the experimental data and maximum adsorption capacity was about 4,6 mg.g-1.

In the present work, red mud derived from TanRai alumina plant was acivated by HCl acid and using as effective adsorbent of phenol from aqueous sloution. The activated red mud was characterized by physico-chemical mehods including X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle distribution. Phenol adsorption ability from aqueous solution onto activated red mud was investigated. With adsorbent’s dosage of 20 g.L-1 and at suitable pH of 7, more than 90 % of phenol was removed from aqueous solution containing 50 mg phenol.L-1. Adsorption isotherm study confirmed Langmuir model well described the experimental data and maximum adsorption capacity was about 3,3 mg.g-1. The kinetic data indicated that the adsorption followed pseudo second-order equation. The negative value of Gibbs free energies proved that the adsorption was a spontaneous process. The endothermic nature of the adsorption with the increase of the chaotic level on solid – liquid surface after taking place the adsorption was demonstrated by the positive values of standard enthalpy and standard entropy.

This study employs the tight-binding density functional method GFN1-xTB to investigate the structural and electronic properties of TiO2-ZnO and TiO2-ZnO composite materials modified by Li, Na, K, and Fe metals. Computational analyses reveal the formation of weak covalent bonds between the TiO2 and ZnO components within the composite system. Doping TiO2-ZnO with metals induces significant alterations in the electronic structure, particularly in terms of ionization energy and global electrophilic index. The UV-VIS spectra are calculated using real-time time-dependent density functional theory with xTB Hamiltonians. The obtained results demonstrate minimal impact of metal presence on the absorption spectrum of TiO2-ZnO, but significant influence on the recombination potential of photogenerated charge carriers. It is suggested that Fe/TiO2-ZnO and Li/TiO2-ZnO will demonstrate higher photocatalytic activity than the pristine TiO2-ZnO material.

Nanoflower MoS2, nanowire TiO2(NNW) and 3D MoS2/TiO2 nano-heterostructure have been synthesized successfully by simple typical hydrothermal reaction method followed by 200oC calcination under an argon atmosphere. The prepared samples are characterized in detail by XRD, FESEM, UV-vis DRS, EDX and BET. The results suggest that the TiO2 NNW is successfully coupled with MoS2 to form the heterojunction nanostructure. The hybrid heterostructures can effectively utilize visible-light and solar energy to degrade 2,4-dichlorophenoxyacetic acid (2,4-D). The degradation rate of 2,4-D is as high as 99%. The improved photocatalytic activity owes to the decreased band-gap and the heterosurface properties of MoS2/TiO2, promoting the electron-hole pairs separation and absorption capacity to visible light. This work presents a facile approach for fabricating the MoS2/TiO2 heterostructures for efficient photocatalytic 2,4-D solution, which will facilitate the development of designing photo catalysts applied in environment and energy.

The paper reported synthesizing 1,4-dihydropyridine (1,4-DHP) from β-ketoester, aromatic aldehyde, and ammonium acetate via a two-step, using heterogeneous catalyst Amberlyst-15 in high yields at room temperature. The method was applied to synthesize some 1,4-DHP derivatives. Moreover, the catalyst was reused at least five times without loss of catalytic activity under eco-friendly conditions.

Photoelectrochemical water splitting is of great attention due to its environmentally friendly generation of clean fuels. Hematite (α-Fe2O3) is considered a promising candidate due to its intrinsic properties for the high-performance photoelectrochemical electrode, such as favorable bandgap (2.0–2.2 eV), a suitable energy band position non-toxicity, low cost, and excellent chemical stability. Herein, we report about Sn-doped hematite nanorods and their implementation as photoanodes for photoelectrochemical water splitting. We provide the simple but efficient route to incorporate the Sn into the hematite without structural damage in the nanostructure and scrutinize the effect of Sn dopant on the photoelectrochemical activity of the hematite. Sn can be successfully incorporated into the hematite by the two-step heat treatment process, which reveals the enhanced photoelectrochemical responses compared with undoped hematite.  We elaborate on the effect of Sn dopant in the hematite on the photoelectrochemical activities, thereby suggesting the optimum concentration of Sn dopant. 

In the research, we successfully synthesized WO3/g-C3N4 Z-scheme heterojunction for photocatalytic degradation of tetracycline. These synthesized materials have been characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR Spectroscopy), to investigate their crystal phase, morphology and chemical compositions. The synthesized WO3/g-C3N4 Z-scheme heterojunction exhibited novel photocatalytic activity for the degradation of Tetracyline even under visible light. This was due to photo-excited electrons in the conduction band of WO3 transferred to the valence band of the g-C3N4 preserving electrons in the conduction band of the g-C3N4 and holes in the valence band of WO3. These electrons and holes would react with oxygen and water to produce oxidative radicals for effective degradation of Tetracycline. The synthesized WO3/g-C3N4 photocatalytically degraded approximately 56 % Tetracycline 10 ppm when it was irradiated by visible light of 32 W for 90 mins.