Chemistry of Inorganic Materials最新文献

This investigation delves into the inhibitory impact of Caesalpinia crista (Kanchaki) seed extract (CCE) on the corrosion of aluminium alloy (AA6061) at temperatures varying between 303 and 333K, employing Potentiodynamic Polarisation (PDP), Electrochemical Impedance Spectroscopy (EIS), and weight loss methodologies. Findings demonstrate that CCE extract effectively safeguards Al against corrosion, with efficacy increasing at higher concentrations. The observed inhibitory action exhibits a cathodic-type behavior across all concentrations and temperatures, aligning well with Langmuir isotherm. Notably, the highest level of inhibitory efficiency, reaching 96.87 ​%, is attained at a concentration of 2.0 ​g/L and a temperature of 303 ​K for 3 hours. Consistency is observed between the results obtained through EIS and PDP. A plausible mechanism for preventing corrosion in Al alloy is proposed. Surface analysis techniques, such as Atomic Force Microscopy (AFM) and Scanning Electron Microscopy/Energy Dispersive X-ray analysis (SEM/EDX), validate the adsorption of the inhibitor onto Al alloy surfaces. Morphological examinations corroborate electrochemical findings, confirming protection against uniform corrosion in HCl solutions. Additional analyses involve the computation of activation energy and thermodynamic parameters, with a thorough discussion of the results.

Stable decaphenylcyclopentasilane (DPPS) hole transport layers were developed for guanidinium-, formamidinium-, or ethylammonium-added double-stacked CH₃NH₃PbI₃ perovskite photovoltaic devices without using 2,2′,7,7′-tetrakis (N,N-di-p-methoxyphenylamino)-9,9′-spirobifluorene, which is a typical hole transport layer. Stacking two types of perovskite compounds inserted within the DPPS layer enabled the fabrication of stable perovskite solar cells under ambient atmosphere at 190 ​°C, which reduced the trap density and improved the photovoltaic properties of the devices. As expected, the DPPS-inserted layers functioned as a stable hole transport layer for perovskite solar cells.

Solutions containing hydrofluoric acid (HF), hydrobromic acid (HBr) and bromine (Br₂) were investigated as novel acidic, NO_x-free mixtures for wet-chemical etching of silicon wafers. HF–Br₂-mixtures exhibit isotropic etching behaviour towards silicon, etch rates up to 4.0 ​μm ​min⁻¹ were observed at room temperature, which are higher than the etch rates of commercially used alkaline solutions. HF–HBr–Br₂-mixtures show anisotropic etching behaviour, texturing the surface of monocrystalline silicon wafers with random upright or random inverted pyramidal structures. Etch rates up to 2.4 ​μm ​min⁻¹ were observed, the etch rate increases linearly with the concentration of Br₂ in the etching solution. Silicon surfaces were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The light trapping efficiency of wafers etched by HF–HBr–Br₂ solutions was compared to commercially available textured wafers by UV/Vis-reflectivity measurements indicating lower reflectivities for the HF–HBr–Br₂-treated samples. A reaction scheme for the anisotropic dissolution of silicon in bromine-containing aqueous HF-solutions is proposed, which involves bromine as oxidizing agent.

Advanced oxidation processes have attracted considerable attention for wastewater treatment, air purification, CO₂ reduction and many more pollution control applications. Environmentally friendly (K_0.5Na_0.5)NbO₃ (abbreviated as 'KNN') is emerging as a lead-free photocatalyst due to its good piezoelectric response and high Curie temperature. In this work, KNN photocatalysts were synthesized by two methods i.e. solid-state and sol-gel routes and abbreviated as KNN-SS and KNN-SG, respectively. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the orthorhombic structure for both the samples. Morphological studies were done using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Average particle size was estimated using ImageJ software which is to be around 1.38 ​μm and 278 ​nm for KNN-SS and KNN-SG samples respectively. Zeta potential measurements estimated the average surface charge on the particles i.e. 67.099 ​mV for KNN-SS and 69.115 ​mV for KNN-SG samples. Tauc’ plot was employed to find the optical bandgap, which was estimated around 3 ​eV for both the samples. Photoluminescence (PL) spectroscopy confirmed that KNN-SG sample has a lower recombination rate than KNN-SS sample as it exhibited lower emission intensity. Better photocatalytic result of 92.8 ​% degradation of methylene blue dye in just 80 ​min has been observed for KNN-SG sample, indicating smaller particle size causes delayed recombination, which enhances higher photodegradation of the material. Lead-free ferroelectric KNN samples with smaller particle sizes can be a promising candidate for these effluents.

For n-i-p typed flexible perovskite solar cells (fPSCs), the doped hole transport layer significantly impacts the devices' long-term stability. Using dopant-free organic hole transport materials (d-HTMs) is promising for stable fPSCs. However, the low conductivity of d-HTMs limited their thickness, making them sensitive to the surface morphology of the perovskite film's upper surface. Here, we report a chemical polishing strategy using 1-hexyl-3-methylimidazolium acetate (HMIM∙Ac) as the polishing reagent to enhance the upper surface of the perovskite film, which could form a smooth and flat surface. Meanwhile, the treatment can reduce surface defects and smaller grains on top of the surface. Then, we deposite an ultra-thin dopant-free PM6 layer, a typical hole transport layer, on top of the polished perovskite film. The PM6 layer shows an improved face-on orientation and then carrier mobility. Moreover, suppressed non-radiative recombination at the perovskite/PM6 interface is also observed, translating into a higher open-circuit voltage and fill factor of the fPSCs. As a result, a champion power conversion efficiency (PCE) of 17.76 ​%, with an open-circuit voltage of 1.025 ​V and fill factor of 78.2 ​%, is obtained, which is one of the highest PCEs among the reported fPSCs based on d-HTMs. Our strategy demonstrates a facile but effective way of developing high-efficiency and stable fPSCs for future applications.

The slow evaporation solution method was employed to synthesize and crystallize zinc chloride doped α-glycine (ZCAG) single crystals. The single crystal X-ray diffraction studies of pure α-glycine single crystals revealed that the structure belong to primitive monoclinic lattice. Powder X-ray diffraction studies of ZCAG showed the well-defined sharp peaks and formation of centrosymmetric structure with space group P21/n. The increase in lattice volume of ZCAG suggested that the access of zinc chloride into the α-glycine crystal and the entry of zinc chloride to the α-glycine crystal was also established from the energy-dispersive X-ray analysis. Fourier transform infrared spectrum of ZCAG revealed that the functional groups of α-glycine was not transformed due to the introduction of zinc chloride into the lattice. The optical transparency of ZCAG was observed in the UV–visible region, and it exhibited a superior transmittance in the visible region. Energy bandgap value was determined and found to changes while increasing the dopant concentration. An emission peak was observed in the violet region from the photoluminescence spectra. The centrosymmetric ZCAG exhibited second harmonic generation efficiency of 1.44 times higher than standard potassium dihydrogen phosphate, possibly due to local non-centrosymmetry in the lattice, which is further augmented by lattice distortion induced by the dopant. Low dielectric constant and loss of the grown ZCAG crystals showed the remarkable application of non-linear optical. The Meyer index indicates that the grown ZCAG are categorized as soft materials.

The structural, optical, morphological, and catalytic behavior of the spinel cobalt chromite nanoparticles (NPs), which were successfully synthesised using a simple co-precipitation method, are investigated in this work. First, the catalytic performance test was used to determine the ideal doping Sr and doping amounts. The as-prepared sample's face-centered cubic spinel structure is confirmed by the powder X-ray diffraction pattern, and the average crystallite size is determined to be 22–15 ​nm. The prepared material had a structure resembling nanoparticles, and the SEM analysis showed that the size attained was approximately 28–16 ​nm. TEM analysis revealed that the prepared material and sizes had a hexagonal-like structure. DRS and PL spectra were used to determine the optical absorption and photoluminescence emissions, respectively. Decolorization of 4-Nitrophenol's yellow color is another area of interest in the catalytic characteristics of CoCr₂O₄ crystals doped with Sr. The catalysts employed were discovered to be readily recyclable and effective catalysts for the oxidation of styrene, with benzaldehyde as the end product.

The present manuscript focuses on important aspects regarding TiO₂, which is typically used in many applications. On one hand, a thorough review of methods for synthesizing nanostructured TiO₂ is presented. Using these methods, and different post-synthesis heat-treatment conditions, close to thirty TiO₂ materials have been prepared, and their porous texture and crystalline and amorphous structure have been characterized. In this large number of samples, the porous texture characterization has revealed a high contribution of mesoporosity in a large number of the synthesized materials, being in many materials around 60–70 %. Moreover, different percentages of crystalline phases, anatase, brookite, rutile, and amorphous titania are developed depending on the TiO₂ preparation conditions. These fractions have been determined from X-ray diffraction data using the “simple” characterization method reported by Cano-Casanova et al., inspired by Jensen et al., and Bellardita et al., also exploring its limitations. This analysis has allowed assessing a linear relationship between porosity, particularly between the surface area, and the amorphous phase content in titanium dioxide. A relationship had been previously suggested in the literature, but never correlated in such a way. In summary, the present study constitutes a tool to help other researchers select the most suitable method for synthesizing nanostructured TiO₂ materials with target properties and, also, to characterize them, and have a very easy and straightforward estimation of TiO₂ amorphous phase content after the determination of their surface areas.

This communication describes a highly recyclable, ecologically friendly, ionic liquid catalyst supported by cobalt that is active in the Suzuki-Miyaura reaction at 70 ​°C. To be more precise, the procedure is initiated with a special form of the ecologically safe solvent 3-(2-aminoethyl)-1-methyl-1H-imidazole-3-ium bromide [Aemim]Br. A few benefits of the coupling process include its simplicity of use, broad range of substrate compatibility with high yields, environmental friendliness, high reaction rate, low catalyst loading (0.001 ​mol%), and recyclability (up to 7 cycles).

Reaction between 2-hydroxy-1-naphthaldehyde thiosemicarbazone and square planar dichloro bis triphenylphosphine Cu(II) resulted in two structurally different binuclear Cu(I) tetrahedral complexes which are co-crystallized together by exhibiting bonding isomerism. The reaction of co-crystallized complexes with [NiCl₂(PPh₃)₂] led to C–S and Cu–S activation of coordinated ligand to form [Cu₂(μ₂-Cl₂)(PPh₃)₃] and [Cu₂(μ₂-S₂)(PPh₃)₃] respectively along with a square planar [Ni(nap-tsc)(PPh₃)] (where, nap-tsc =2-hydroxy-1-naphthaldehyde thiosemicarbazone) and triphenylphosphine sulfide.