Facile synthesis of ZnMoO4/AlPO4-5 nanorod composites as visible-light-driven photocatalysts and high-performance energy storage materials

The present article describes the facile one-step hydrothermal synthesis of single-crystalline ZnMoO₄/AlPO₄-5 nanorod composites. The physicochemical properties of the synthesized materials, such as structure, morphology, and bandgap, were determined using techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N₂ adsorption–desorption isotherms, X-ray photoelectron (XPS), ultraviolet-visible (UV-vis), and photoluminescence (PL). The XRD pattern of synthesized ZnMoO₄/AlPO₄-5 verifies the synthesis of nanocomposites. Diffuse UV-vis spectra reveal that ZnMoO₄/AlPO₄-5 nanorod composites exhibit an indirect semiconductor with an optical bandgap between 3.15 and 3.7 eV depending on Mo : Zn ratio. In comparison to pure AlPO₄-5, ZnMoO₄/AlPO₄-5 nanocrystal composites showed significantly higher photocatalytic activity for the degradation of para-nitrophenol (PNP, 0.04 g l⁻¹), with 14, 99, 70, and 54% for AlPO₄-5, Mo : Zn (2)/AlPO₄-5, Mo : Zn (4)/AlPO₄-5, and Mo : Zn (6)/AlPO₄-5, respectively. This result might be attributed to the composite's efficient charge transfer and optimized electron–hole pair recombination. The supercapacitive ability of ZnMoO₄/AlPO₄-5 nanorod composites was also investigated in this work. For the prepared electrodes using AlPO₄-5, Mo : Zn (2)/AlPO₄-5, Mo : Zn (4)/AlPO₄-5, and Mo : Zn (6)/AlPO₄-5, the capacitance values were 400, 725, 450, and 481.25 F g⁻¹, respectively, at a current density of 0.5 A g⁻¹. This study shows that ZnMoO₄/AlPO₄-5 nanorod composites are a potential visible-light-responsive photocatalyst. The electrochemical results further demonstrate the high capacitance of ZnMoO₄/AlPO₄-5 nanorod composites toward energy-storage applications.

Photocatalytic degradation of PNP over single-crystalline ZnMoO₄/AlPO₄-5.

Visible-light Responsive Cu-MOF-NH 2 for Highly Efficient Aerobic Photocatalytic Oxidation of Benzyl Alcohol.. [DOI: 10.21203/rs.3.rs-963756/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The current study focuses on the photocatalytic oxidation of benzyl alcohol in acetonitrile under air bubbling conditions comparing titania-based materials, Cu-MOF, and Cu-MOF-NH2 as semiconductor photocatalysts. The catalysts were characterized by XRD, N2 adsorption-desorption, FT-IR, Raman spectroscopy, and TEM. The photocatalytic benzyl alcohol conversion reached ~ 100% after exposing the four prepared catalysts to a 125W mercury lamp for up to 240 min. Benzaldehyde is formed with a moderate selectivity (after a reaction time of 60 min. ca. 30% over the titania-based catalysts 37%, 45% over Cu-MOF, and Cu-MOF-NH2, respectively). The formation of electron-hole pairs at the surface of the semiconductor nanoparticles followed by oxidation reaction was the suggested mechanism. A first-order kinetic model was observed for the photocatalytic oxidation of the investigated alcohols, and the rate constants were calculated. According to preliminary research, decorating MOF linker by amine (MOF-NH2) could improve visible-light harvesting, charge separation, and electron transport of the resulting catalyst, resulting in increased photocatalytic activity. The current work offers some direction for the development of MOF-based photocatalysts for organic synthesis.

Assessment of polyethylene/Zn-ionic as a diesel fuel sulfur adsorbent: gamma radiation effect and response surface methodology

Irradiated waste high-density polyethylene@Zn/ionic liquid novel composite well-fabricated via coacervation method was irradiated by gamma-irradiation and studied the effect of that radiation on the desulfurization process. The prepared composites were characterized by various analytical techniques as follows: X-ray diffraction (XRD), Fourier-Transform infrared (FT-IR), X-ray photoelectron spectrometer (XPS), scanning electron microscope (SEM), High Resolution Transmission Electron Microscopy (HRTEM), N₂-adsorption-desorption isotherm, and thermal gravimetric analysis (TG/DTA). The adsorptive desulfurization process of benzothiophene (BT) and dibenzothiophene (DBT) which are harmful compounds in diesel model fuel was investigating using the irradiated and unirradiated composite. The results illustrated that the unirradiated and irradiated composites exhibit an adequate adsorption capacity reached (50-75 mg S/g) and (60-85 mg S/g) for BT and DBT, respectively. The adsorption process over the prepared adsorbents follows the pseudo-second-order kinetic models. The irradiated composite exhibited more adsorption capacity than the unirradiated one due to the radiation generated more surface area and created proton-bond donor sites in the composite surface, which increases the interaction between the surface and sulfur species. The adsorption capacity and adsorption percentage for irradiated and unirradiated composites towards (SCCs) were studied using response surface methodology based on the central composite design (CCD). The thermodynamic factors (∆H°, ∆G°, and ∆S°) reveal that these processes are endothermic adsorption processes. The irradiated PEt @Zn/IL was re-used without significant loss of adsorption activity. This novel irradiated PEt @Zn/IL is the first time used as an adsorbent with an advantage that includes its excellent adsorption capacity, which ensures the product will be efficient in a real process such as the petrochemical industry.

Oxidative coupling of bio-alcohols mixture over hierarchically porous perovskite catalysts for sustainable acrolein production

The acrolein production from bio-alcohols methanol and ethanol mixtures using AMnO₃ (since A = Ba and/or Sr) perovskite catalysts was studied. All the prepared samples were characterized by XRD, XPS, N₂ sorption, FTIR, Raman spectroscopy, TEM, SEM, TGA, and NH₃–CO₂-TPD. The catalytic oxidation reaction to produce acrolein has occurred via two steps, the alcohols are firstly oxidized to corresponding aldehydes, and then the aldol is coupled with the produced aldehydes. The prepared perovskite samples were modified by doping A (Sr) position with (Ba) to improve the aldol condensation. The most catalytic performance was achieved using the BaSrMnO₃ sample in which the acrolein selectivity reached 62% (T = 300 °C, MetOH/EtOH = 1, LHSV = 10 h⁻¹). The increase in acrolein production may be related to the high tendency of BaSrMnO₃ toward C–C coupling formation. The C–C tendency attributes to that modification have occurred in acid/base sites because of metal substitution.

The figure illustrates the potential of perovskite as a catalyst for acrolein production via simultaneous oxidative coupling of renewable alcohols (ethanol and methanol) followed by aldol condensation of pre-formed aldehydes to form acrolein.