Oriented Attachment Mechanism Research Articles

General Synthesis of Single-Crystalline Ta2O5 Nanorods Towards Enhanced Photocatalytic H2 Production Activity.

As a potential candidate for photocatalytic H2 production from water splitting, Ta2O5 catalyst presents suitable conduction and valence band positions, but suffers from poor charge transfer ability, which seriously limits its photocatalytic performance enhancement. Here, a facile and eco-friendly hydrothermal method was developed for the fabrication of one-dimensional (1D) Ta2O5 nanorods using the freshly precipitated tantalic acids as the precursors. An oriented attachment mechanism was proposed for the growth of Ta2O5 nanorods. Moreover, the present synthetic approach was further extended to direct synthesis of nine kinds of alkaline tantalates and alkaline-earth tantalates nanostructures, suggesting its general applicability. A significant increase in activity in photocatalytic H2 production was revealed on 1D Ta2O5 nanorods. The improved photocatalytic H2 production activity of Ta2O5 nanorods was mainly attributed to its 1D nanorods structure with high crystallization and large specific surface areas as well as excellent charge transfer efficiency.

Unraveling the transition of ZIF-67-on-ZIF-8 core–shell structured dodecahedron formed by an oriented attachment mechanism from type II to step-scheme for enhanced photocatalytic degradation of oxytetracycline hydrochloride

A composite photocatalyst comprising ZIF-67 and ZIF-8 was synthesized using a hydrothermal method. The process entailed the crystallization of ZIF-67 on the ZIF-8 dodecahedron backbone, eschewing the utilization of ligands. The photocatalytic efficiency of the composite ZIF-67-on-ZIF-8 was evaluated through the degradation of oxytetracycline hydrochloride (OTC) under visible and UV light. The results indicated superior OTC degradation compared to pure ZIF-8 and ZIF-67, which might be attributed to the energy level and lattice alignment between ZIF-8 and ZIF-67. This facilitated the separation and transfer of photogenerated electron-hole pairs, thereby suppressing electron-hole complexation. The activation of ZIF-67-on-ZIF-8 with peroxymonosulfate (PMS) resulted in a further enhancement in the degradation efficiency of OTC under both visible and UV light conditions. The optimal effect was observed with the addition of 0.6 mmol of PMS, which resulted in a degradation rate of 95.7 % at 60 min under visible light and 97.01 % at 30 min under UV light. The acceleration of the degradation process and the reduction in the required time were the result of a change in configuration. The study’s originality led to the transformation of the conventional type II heterojunction model into the S-scheme heterojunction model through the modification of the light source, thereby offering a novel perspective for heterojunction design.

Nanofiber array growth mechanism based on dealloying of Ti-Cu/Cu multilayer precursor film

Metal oxide nanofiber array materials are a type of material with outstanding performance and application potential. Recently, an efficient dealloying method using Ti–Cu/Cu multilayer film as a precursor was proposed to prepare titanium oxide nanofiber array structure. However, the growth mechanism and formation process of such an oxide nanofiber array grown on multilayer-film is not clear. In this work, we use Ti-Cu/Cu multilayer film as the precursor, NaOH solution as the dealloying corrosion solution, and free dealloying at room temperature. On the basis of successfully obtaining TiO2 nanofiber array films, the morphology formation and evolution process of the nanoarray were carefully monitored, and the atomic percentage changes of Ti, Cu and O elements in the dealloying precursor films were tested, as well as the formation and crystalline phase evolution trends of TiO2. Based on the experimental data, we tried to draw a schematic diagram of the formation process of this TiO2 nanofiber array, and proposed that the growth mechanism of the TiO2 nanofiber array is the precipitation growth process both with Ostwald Ripening and Oriented Attachment mechanisms. Then, the photocurrent response characteristics of the obtained nanofiber array structure samples were analyzed, and it was found that the nanofiber array structure had a certain effect on the photocurrent response performance. The completion of the present work is expected to provide a theoretical reference for the preparation and application of other metal oxide nanofiber array by dealloying method.

Insights into the mechanochemical synthesis of nanostructured PbTe: The role of structural defects

Mechanochemical synthesis of nanostructured PbTe, adding isopropyl alcohol during milling, is promoted by the presence of structural defects such as edge dislocations, amorphous zones, grain boundaries, among others. High-resolution transmission electron microscopy observations revealed that the nanostructured PbTe formation is fundamentally dependent upon crystalline imperfections during the high-energy milling process. Even though defect-dependent mechanisms rule the formation of nanostructured PbTe, oriented-attachment mechanism is also traced and contributes to the PbTe formation. Hence, experimentally, isopropyl alcohol is a key parameter for the mechanochemical synthesis of nanostructured PbTe.

Linking experimental findings and theoretical insights on the mechanochemical synthesis of PbTe quantum dots: The effect of ethylene glycol

It is provided a new pathway for obtaining the formation of small dimensional PbTe nanostructures during milling, including quantum dots (QDs). It is possible via the addition of ethylene glycol (EG) which is the key factor to decide the final morphology and size of small dimensional PbTe nanostructures. Therefore, in this work, the effects of EG, as a process control agent (PCA), on the growth mechanisms of PbTe QDs are experimental and theoretically investigated. To achieve this goal, the behavior between EG and inorganic PbTe interface interactions is explored via density functional theory (DFT). The occurrence of PbTe is detected by using X-ray diffraction technique and the mechanical kneading suppression is verified through electron microscopy results. The formation of rounded and quasi faceted PbTe QDs are ruled by structural-defect and imperfect oriented attachment mechanisms respectively, which are strongly evidenced by high-resolution transmission electron microscopy. Interactions between EG and low-index surfaces are modeled by dispersion-corrected DFT calculations. Through the electrostatic potential mapped on the van der Waals isosurfaces, adsorption modes of the selected PCA on the PbTe surface are proposed, allowing rationalizing the facets exposed by the PbTe QDs after the surface treatment. Changes induced by the EG molecule, as PCA, are rationalized in terms of surface energy. Interactions with the PbTe surfaces stabilize the (100) facet, while destabilize the (111) facet. Wulff constructions support the formation of particles, in the nanometric scale, with cubic or cubic with rounded edges.

Defect related photocatalytic and photoluminescent characteristics of Gd-doped SnO2 nanoparticles with different shapes

A new method for the preparation of Gd-doped SnO2 nanoparticles based on the precipitation method followed by hydrothermal treatment has been developed. Two different shape series of nanoparticles with different Gd content were obtained and fully characterized. Wide number of parameters, including lattice parameters, crystallite size, particle size, surface composition, oxygen vacancies, structural defects, band gap energy, luminescent spectra, band structure and density of states were determined.It was shown that the mechanism of oriented attachment of nanoparticle growth is stimulated during hydrothermal treatment. Quantum computer calculations of the interaction energies of oriented nanoparticles were performed and the role of ions in the reaction media was revealed.A study of the photoluminescence of the obtained nanoparticles was carried out, showing a blue photoluminescence corresponding to the oxygen vacancies, indicating their presence.Photocatalytic activity of nanoparticles when irradiated with visible light was shown, which is explained by quantum chemical calculations and demonstrated in the example of a colored solution of the organic dye methylene blue. The relation between the morphological and structural properties of nanoparticles and their photocatalytic properties has been studied in detail. A high degradation percentage is achieved using a regular commercially available LED lamp with a visible light spectrum.Novelty of the work lies in obtaining series of samples with various parameters, detailed studies of oriented attachment mechanism and impact of the nanoparticle parameters on photocatalytic properties. A concept for the development of efficient photocatalysts based on chemical and computational experiments is proposed.

Multifunctional Tb-doped SnO2 based photocatalytic agent for water remediation: Study of defect-related properties

A new methodology to obtain Tb-doped SnO2 nanoparticles based on precipitation method followed by hydrothermal treatment was developed. Two series of nanoparticles with various Tb concentrations were fully characterized with large number of methods, including XRD method, FTIR, XPS, and Raman spectroscopy, TEM imaging, SSA estimation, optical transmittance study, luminescence spectroscopy and quantum-chemical calculations.The oriented attachment mechanism of nanoparticle growth is shown to occur under hydrothermal treatment. Computational study of interaction energies of mutually oriented nanoparticles and role of ions in the synthesis media was performed. Study of photoluminescence characteristics of the obtained nanoparticles is provided. The presence of blue and green luminescence is shown. The blue luminescence is related to SnO2 self-luminescence, while the green is related to Tb. Increase of Tb concentration suppress blue self-luminescence of SnO2, and promote green luminescence due to an increase of the energy transfer from crystal host to doping Tb ions.The nanoparticles are shown to possess photocatalytic activity of 97–100% under Vis light irradiation. Using a complex of modern physicochemical methods, a new factor affecting photocatalytic efficiency was revealed – the ratio of vacancies to defects (Vac/Def). A clear dependency of photocatalysis and normalized Vac/Def ratio to interaction energy between pollutant and catalysts surface is explained via quantum-chemical calculations for the first time, and demonstrated on examples of colored solution of organic dye methylene blue and colorless solution of oxytetracycline. Detailed study of the relation between morphological and structural properties of nanoparticles and their photocatalytic properties is provided. High degradations percent are achieved under simple LED light bulb. A concept of a chemical and computational experiments-based route for the development of effective photocatalysts is suggested.

Identifying the effect of tributyl phosphate on the growth of PbTe quantum dots: Linking experimental and theoretical approaches

The effects of tributyl phosphate (TBP), as a process control agent (PCA), on morphology, size and dispersion of PbTe quantum dots (QDs), at 5 h of milling time, are investigated. By using X-ray diffraction, the occurrence of PbTe is detected, while the PbTe formation and morphology, during milling, are studied via transmission electron microscopy (TEM). According to TEM results, the occurrence of nearly spherical and faceted PbTe QDs are ruled by highly structural-defect and oriented attachment mechanisms, respectively. What is more, mechanical kneading is effectively inhibited when 3 wt% TBP is added during milling. Dispersion-corrected density functional theory (DFT) calculations are carried out to understand the factors that affect growth and morphology of PbTe QDs. DFT results demonstrated that both the intrinsic characteristics of PbTe and the adsorption of certain reaction species are responsible for the shape control of PbTe QDs, which is useful to propose adsorption modes of TBF on PbTe surface and to rationalize the facets exposed by PbTe after the surface treatment. In agreement with experimental results, Wulff constructions proposed are cube-like quantum dots with sharp edges, but rounded edges are possible as well.

Progressively Oriented Attachment-Enabled Ultralong Single-Crystalline Upconversion Nanowires for Multidirectional Strain Sensing.

Fabricating one-dimensional (1D) single-crystalline nanostructures with the necessary characteristics for interconnects and functional units in nanodevices poses a major challenge. Traditional solution-based synthesis methods, driven by oriented attachment mechanisms, have limited the growth of either ultrathin crystalline nanowires or short rod-like nanocrystals due to stringent orientation requirements. The construction of single-crystalline ultralong nanowires with both an elongated length and moderate thickness has remained elusive. Here we introduce a growth mechanism based on progressively oriented attachment that enables the attachment of larger crystals while preserving the alignment of the crystal lattice. Using this mechanism, we achieve 1D single-crystalline lanthanide-doped nanowires (K2YF5:Yb/Er) with lengths up to 9 μm and a moderate thickness of approximately 20 nm. These nanowires can be integrated into a flexible film that exhibits stretching-dependent upconverted luminescence behavior. The mechanical toughness and elongated morphology of the nanowires facilitate the development of a wearable device dedicated to multidirectional strain sensing with high responsivity and excellent stability, withstanding repeated stretching and releasing for up to 1000 cycles.

Ordered CoIII‐MOF@CoII‐MOF Heterojunction for Highly Efficient Photocatalytic Syngas Production

Photocatalytic Syngas Production In article number 2200085, Mingxiong Lin, Zanyong Zhuang, Yan Yu, and co-workers report the construction of an ordered CoIII[email protected]II-MOF heterostructure based on a spontaneous oriented attachment mechanism. CoIII-PBA exerts stronger affinity for CO2 molecules than CoII-PBA, and thus serves as the active sites, and the built-in electric field in the CoIII[email protected]II-PBA heterojunction can direct the fast transport of photogenerated electrons from CoII-PBA to the active CoIII-PBA.

Ultrathin Graphdiyne Nanowires with Diameters below 3 nm: Synthesis, Photoelectric Effect, and Enhanced Raman Sensing.

Due to the intrinsic layered structure, graphdiyne (GDY) strongly tends to form 2D materials, therefore, most of the current research are based on GDY 2D structures. Up to now, the synthesis of its ultrathin nanowires with a high aspect ratio has not been reported. Here, the ultrathin GDY nanowires with diameters below 3 nm are reported for the first time by a two-phase interface synthesis method, which has excellent crystallinity and an aspect ratio of more than 2500. Evidence shows that the GDY ultrathin nanowires are formed by the oriented-attachment mechanism of nanoparticles. The GDY ultrathin nanowires exhibit a significant quantum confinement effect, enhanced photoelectric effect, and promising applications in surface-enhanced Raman sensing.

Synthesis of Silver Nanowires Using a Polyvinylpyrrolidone-Free Method with an Alpinia zerumbet Leaf Based on the Oriented Attachment Mechanism.

In this study, silver nanowires (AgNWs) were successfully synthesized by using a polyvinylpyrrolidone (PVP)-free hydrothermal method with an Alpinia zerumbet leaf chunk as a reducing agent and template. Meanwhile, the mechanism of biomass synthesis of AgNWs is also explored. The AgNWs have a diameter of ∼77 nm and a length of ∼10 μm. During the hydrothermal process, the biomass initially serves as a reducing agent to reduce silver ions. As the reaction proceeds, the biomass will form a pipe-shaped soft template by hydrothermal carbonization. Silver ions are adsorbed and reduced along the pipe-shaped soft templates to form silver nanorods, and adjacent nanorods are merged to AgNWs. Thus, AgNWs are grown along the pipeline soft template based on the oriented attachment mechanism. Inspired by this, the mechanism of the polyol method was further investigated. In the initial growth stage, AgNWs synthesized by the polyol method have a V-shaped notch. Therefore, AgNWs synthesized by the polyol method may also grow on the basis of the oriented attachment mechanism with PVP as a template.

Deep tuning of Bi2Te3 nanostructures suitable for thermoelectric waste heat recovery: The impact of pH on crystal growth in hydrothermal synthesis

Bi2Te3 nanostructures were synthesized through a facie hydrothermal method. A comprehensive and systematic investigations on the effect of pH, on the purity, crystallinity, size and morphology of synthesized nanostructures were carried out. Bi2Te3 nanoparticles, nanoplates, nanoflowers and nanotubes were obtained at different pH ranges. Based on the XRD, FESEM, EDAX and HRTEM observations, a detailed growth mechanism is proposed, which shed light on the formation of primary Bi2Te3 nanoplates and the hierarchical nanostructures. Oswald ripening process is identified as the dominant growth mechanism at lower pH values. Under alkaline environment, an imperfect oriented attachment mechanism leads to evolution of nanostructures with diverse morphology from primary Bi2Te3 nanoplates. The three-dimensional nanostructures offer themselves as good thermoelectric materials due to their reduced thermal conductivity owing to the phonon scattering centres. In addition, the quantum confinement effect and the morphological fluctuation in the obtained nanostructures may improve the thermoelectric performance by resulting modified energy band structure.

Void space and secondary oriented attachment mechanisms in cerium oxide nanorods

Two new processes occurring during nanorod annealing of ceria are disclosed, both belonging to the wider “oriented attachment” (OA) scheme of crystal growth, which commonly drives nanoparticles growing into nanorods. The first new process is an inversion of the standard OA, where the usual solid particles are replaced by well-facetted shape-equilibrated voids inside larger single crystals. The internal facetted voids are then found to aggregate during dry heat treatment into rod-shaped elongated voids growing eventually towards nanotubes. For the case of CeO2, a perfect equivalence is found between positive OA, involving cuboctahedral {111}/{100} nanoparticles turning into {110}/{100} nanorods, and negative or void space OA, where cuboctahedral voids turn into negative tubular rods of same indexing. The second OA process (“secondary OA”) concerns aggregation of small nanorod segments into larger, double, or quadruple sized nanorods, with perfection of alignment and bonding exceeding simple van der Waals forces. Eventually, the new rods merge into single crystal grain boundary–free larger rods, but with an external shape, including double-ended rods, indicating their origin from several rods. Both processes are found on identical samples and occur in parallel.

Nano-Architectural Design of V2O5 for High-Performance Lithium-Ion Battery Cathode

Recently, the quest for lithium-ion batteries (LIBs) with higher energy densities, power densities, and low cost has gained great attention due to the increasing demands of high-power equipment such as electric vehicles. One of the most promising approaches to enhance the energy densities of LIBs is to couple the anode with a high-capacity cathode, since the capacity of LIBs is typically limited by the cathode. Among the high-capacity cathode materials, vanadium pentoxide (V2O5) is receiving attention due to its exceptional theoretical capacity (~294 mAh g-1) [2]. Also, since the V2O5 has no lithium in the chemical, it can increase the specific energy in the cell design of the lithium-metal battery (LMB, ~700 Wh kg-1). Moreover, it needs no first charge enhancing the initial cycling stability of the LMB.However, it suffers from a poor cycling stability and rate capability due to its structural transformation during cycling and low electrons/lithium-ion conductivities [2]. To overcome this issues, numerous efforts have been focused on shortening the lithium ion (Li+) diffusion length through the development of nanostructured V2O5 such as nanorods, nanobelts, nanosheet, and hollow spheres. Particularly, 1D nanostructured V2O5 along the [010] orientation, which is the fastest growth direction of V2O5 [4], has been suggested in many studies because of its simplicity in synthesis [1]. In nanostructures, however, structural collapse and particles agglomeration could emerge during Li+ ion penetration [3]. Moreover, the [010] direction of V2O5 corresponds to the energy-preferred diffusion pathway of Li+ ion [5]. Accordingly, 1D nanostructured V2O5 provides a long distance for the Li+ ion diffusion along [010] direction. Therefore, it is assumed that to achieve the high kinetics and structural stability, the structure for V2O5 as cathode materials should be re-designed to satisfy the following conditions, favorable to Li-ion accommodation and its pathway : ⅰ) secondary structures consisted of primary nanostructured units to prevent agglomeration. ii) a short [010] length with highly exposed (010) facets to shorten a Li+ ion diffusion pathway and facilitate the Li+ ion intercalation reactions.In this context, we introduce a facile lithium-treatment method for synthesis of nanoplates-stacked structured V2O5 (Li-treated VO) with highly exposed (010) facets and shorter [010] growth-length (0.7-1.4 um) compared to a V2O5 nanobelt (~20 um) (pristine VO). In lithium-treatment method, Li+ ions from lithium nitrate (LiNO3), which is added to precursor solution, can inhibit the complete crystallization of V2O5 during hydrothermal process, hence evolving xerogel/crystal composite. Afterward, during heat treatment process, the cleavage and oriented attachment mechanism are accompanied, generating Li-treated V2O5 with nanoplates-stacked structure having short [010] length and highly exposed (010) facets (Figure 1). The robust nanoplates-stacked structure can facilitate the fast and efficient transportation of Li+ ion into the [010] channel. In Li//V2O5 half-cell, the Li-treated VO electrodes can achieve a reversible capacity of 252 mAh g-1 at 50 mA g-1 in the voltage range of 2.05–4.0 V (vs. Li/Li+) (Figure 2). Notably, the Li-treated VO electrodes also exhibit a higher rate performance (140 mAh g-1 at 1 A g-1 (Figure 2)) and cycling capability (79 % capacity retention after 100 cycles (Figure 3)) compared to the untreated V2O5 nanobelt (VO) electrodes. In addition, the reversible lithium intercalation reaction and structural stability of Li-treated VO will be discussed in detail.

Template-Free Hydrothermal Synthesis of Octahedron-, Diamond-, and Plate-like ZrO2 Mono-Dispersions.

Anisotropic ZrO particles with octahedron-, diamond- and plate-like morphologies are successfully synthesized by a facile hydrothermal treatment approach using NaBF as mineralizer. The concentration of mineralizers play a crucial role on the formation of shape-controlled ZrO particles thus affect the particle size. With the increasing concentration of mineralizer, the crystalline sizes of the primary single-crystal and the secondary particle size both increase. With the introduction of NaBF, F plays an essential role in tuning the crystallinity and size of primary ZrO nanorods along [001] direction. The synergistic effect of F and B result in different epitaxial growth rate. And the secondary particles mainly crystallize on the small primary nanoparticles through the oriented attachment mechanism. The as-prepared ZrO particles with different sizes and shapes exhibit different photocatalytic efficiency for the degradation of organic dyes. Under UV irradiation, the highest MB degradation rate of 88% was observed within 60 min for ZrO photocatalyst synthesized with 0.01 mol/L NaBF mineralizer.

Abnormal grain growth in BaTiO3 nanoceramics by oriented attachment mechanism

The abnormal grain growth (AGG) behaviour was reported during the solid-state sintering of a nano-sized BaTiO3 powder using the spark plasma sintering technique. Microstructural observations revealed that coarse crystals containing large amounts of faceted pores burst into formation within minutes. The results challenged the traditional views that sintering was predominated by the atom-diffusion related processes. Instead, the phenomena were explained to be resulted from the oriented attachment of smaller BaTiO3 grains. A modified two-sphere model for nanoceramic sintering was also proposed.

Nanoplates-Stacked Vanadium Oxide Cathode Employing Higher Kinetics and Stability in a Lithium-Ion Battery

In recent years, the popularity of high-power equipment such as electric vehicles demands a higher the energy density, higher the power density, and low cost in lithium-ion batteries (LIBs). The capacity of LIBs is typically limited by the cathode. For example, in LIBs based on LiCoO2//graphite system, which have achieved great success in commercialization, the reversible capacity of LiCoO2 (~137 mAh g-1) is lower than that of graphite (~370 mAh g-1) [1]. Hence, it is necessary to improve the capacity of the cathode in order to improve the performance of LIBs. Among the cathode materials, Vanadium pentoxide (V2O5) is considered as one of the ideal next-generation electrode materials due to its high theoretical capacities (294 mAh g-1), high energy densities, good safety and low cost [2]. Nevertheless, its cycle performance and poor rate-capability caused by severe structural changes during the repeated lithiation/de-lithiation, slow diffusion of lithium ion (Li+), and low electrical conductivity hinders its commercialization [2]. Various attempts to fabricate the nanostructured V2O5 such as nanorods, nanobelts, nanosheet, and hollow spheres have been pursued to remedy the issues. The nanostructures are used to overcome their kinetic limitation by reduction of Li+ ion diffusion distance and increase in the electrode/electrolyte contact area. In nanostructures, however, structural collapse and particles agglomeration could emerge during Li+ ion penetration procedure [3]. In particular, many studies have focused on the 1D nanostructured V2O5 in length along [010], the fastest growth direction of V2O5, because of its simplicity in synthesis [4]. However, 1D-nanostructured V2O5 has long Li+ ion diffusion distance along [010] direction, which is corresponding to the energy preferred Li+ ion diffusion path [5]. 1D diffusion along the short [010] direction in V2O5 can be the fast Li+ ion diffusion path for cathode in LIBs. Therefore, to design an optimal structure for V2O5 as cathode materials, the following conditions should be satisfied: ⅰ) structures consisted of primary nanostructured units to prevent agglomeration. ii) a short [010] length with high percentage of exposed (010) facets to shorten a Li+ ion diffusion path and facilitate the Li+ ion intercalation reactions.In this context, we fabricated nanoplates–stacked V2O5 (Li-treated VO) through Li-treatment method in hydrothermal synthesis followed by heat treatment. Li+ ions from lithium nitrate (LiNO3), which is added to precursor solution, can inhibit the completely phase transition from xerogel to crystal during hydrothermal process, leading to formation of xerogel/crystal composite. During following heat treatment process, the cleavage and oriented attachment mechanism are accompanied, evolving nanoplates–stacked V2O5 with short [010] length and highly exposed (010) facets (Figure 1). The Li-treated VO electrodes could facilitate the fast and efficient transportation of Li+ ion into the [010] channel. In particular, the Li-treated VO electrodes can achieve a reversible capacity of 252 mAh g-1 at 50 mA g-1 in the voltage range of 2.05–4.0 V (vs. Li/Li+) (Figure 2). Notably, the Li-treated VO electrodes also exhibit a higher rate performance (140 mAh g-1 at 1 A g-1 (Figure 2)) and cycling capability (79 % capacity retention after 100 cycles (Figure 3)) compared to untreated V2O5 nanobelt (VO) electrodes. In addtion, the reversible lithium intercalation reaction and structure stability of Li-treated VO are confirmed by further analyses. Figure 1

Colloidal synthesis of CdTe nanoplatelets using various cadmium precursors

Two-dimensional (2D) CdTe nanoplatelets were synthesized using cadmium propionate, acetate and myristate precursors. Growth of nanoplatelets within the temperature range of 180–250 °C was monitored with optical absorption, PL spectroscopy and transmission electron microscopy. Continuous growth of NPLs was observed for hydrophobic propionate and myristate precursors at low temperatures, while in the presence of cadmium acetate Ostwald ripening occurs at high growth temperature. It is shown that zinc blende CdTe nanoplatelets with (00l) truncation axis grow by lateral expansion with oriented attachment mechanism. The presence of monomers is considered of major importance for oriented attachment. The growth conditions and duration time were optimized to provide homogeneous CdTe nanoplates.

SnO2 nanoparticles with different aspect ratio and structural parameters: fabrication, photocatalytic efficiency dependences and fast organic dyes degradation

A synthetic approach to obtain nanoparticles of different sizes and shapes via hydrothermal treatment was developed. It was shown that hydrothermal treatment engage oriented attachment mechanism of nanoparticle formation. Obtained nanoparticles were filly characterized by a wide set of methods, their structural parameters were studied and correlations of later with the synthesis procedure were shown. A series of nanoparticles of various sizes and shapes were tested as photocatalysts for cyclic organic pollutants. Fast photodegradation (100% within 10 min) of methylene blue and rhodamine 6G under UV light was achieved. Degradation mechanism was studied, taking into account adsorption stage, pollutant-nanoparticle surface interactions and vacancies to defects ratio, involving computer calculations. A key factor affecting photocatalytic efficiency was revealed.