Crystal Morphology Research Articles

Revisiting the phase transition of PbF2 in solution

The β → α phase transition of PbF2 driven by hydroxide ions was studied in aqueous solution, and by characterizing the crystal phase and morphology during the transformation process. The phase transformation of PbF2 is essentially a process of dissolving and re-precipitating. The phase transition from β-PbF2 to α-PbF2 in aqueous solvent was conducted by adjusting the pH value of the solution. β-PbF2 was stable when immersed in aqueous solutions with pH varying from 1 to 5, and β-PbF2 transformed into α-PbF2 when the pH of the aqueous solution varied from 6 to 9. β-PbF2 cannot transform to α-PbF2 in a non-aqueous solvent (weak polarity solvents) due to poor solubility of β-PbF2. Pure crystalline phase PbF2 (α and β) was synthesized in aqueous solutions by controlling the concentration of hydroxide ions and in a non-aqueous solvent (weak polarity solvent) by controlling the molar concentration ratio of fluoride to lead ions.

The Biological Crystals in Chamid Bivalve Shells: Diversity in Morphology and Crystal Arrangement Pattern

Chamid bivalves are marine organisms that live in high-energy environments and are cemented to hard substrates. To avoid shell damage, the organisms form thick, densely ornamented shells. Shell material consists of aragonite, and the ornamentation may be either aragonitic or calcitic. The latter can be developed as scaly spines, rows of blades, or comarginal, radial arched lamellae. We investigated biological crystal morphology and mode of assembly of Chama arcana and Chama gryphoides shells. Structural characteristics were obtained from electron backscatter diffraction (EBSD) measurements, complemented with laser confocal and BSE imaging. We found a wide range of crystal morphologies and sizes, ranging from irregularly shaped calcite and/or aragonite prisms to tiny and thin aragonite laths. We observed four different modes of crystal assembly patterns: 1. strongly interlocked dendritic calcite units forming the ornamentation blades; 2. aragonite laths arranged to lamellae forming the outer shell layer, the layer adjacent to the calcite; 3. aragonite laths arranged into blocks comprising inner shell layers or aragonitic ornamentations; and 4. shell portions consisting of aragonite prisms, structured in size and crystal orientation, at muscle attachment sites. These four different types of crystal arrangements were observed for the shells of the investigated chamid species; however, they had slightly different strengths of structuring and slight variations in crystal organisation. Additionally, we observed unique microstructural features in Chama shells: We report ornamentation crystals resembling idiomorphic calcite and novel, twinned entities found at the changeover between the aragonitic layers. We highlight and discuss these differences and anomalies in this contribution.

Yellow electroluminescence from metastable zinc silicate in an electrolyte-assisted silicon semiconductor structure

Electrolyte-assisted semiconductors have garnered significant attention as a novel type of semiconductor device due to their unique properties. Notably, the electrolyte-assisted electroluminescent (EEL) device offers several advantages, including a simple structure, low operating voltage, and reduced need for band engineering compared to conventional EL devices. However, achieving practical applications for EEL devices remains challenging due to their inherent issues. In this study, we introduce a yellow-emitting EEL device that utilizes a metastable β-phase Zn2SiO4:Mn2+ film as the optically functional material. The film is prepared using a cost-effective process, optimizing both the crystallization temperature and the concentration of Mn2+. Additionally, we employ a non-toxic aqueous NaCl as the electrolyte in the device setup. The crystal phase, morphology, optical, and electrical properties, along with reliability, are comprehensively investigated in our study. The results highlight the significance of our proposed work in advancing the development of electrolyte-assisted semiconductors within the realm of silicon photonics.

Strong Magnetic p-n Heterojunction Fe3O4-FeWO4 for Photo-Fenton Degradation of Tetracycline Hydrochloride

With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are more environmentally friendly, efficient and applicable to a wider range of organic compounds. FeWO4 was used in this study as the iron-based semiconductor material to modify and optimize the material design. Fe3O4/FeWO4 composites were prepared by a two-step hydrothermal method. The crystal structure, surface morphology, electrochemical properties and separability of the composite semiconductor were analyzed by XRD, XPS, UV-vis, SEM, EDS and Mott-Schottky. The results showed that, when the initial contaminant concentration was 30 mg/L, the initial solution pH was 4, the dosage of the catalyst was 25 mg and the dosage of hydrogen peroxide was 30 μL, the degradation efficiency of tetracycline hydrochloride (TCH) could reach 91% within 60 min, which was significantly improved compared to the performance of the single semiconductors Fe3O4 and FeWO4. In addition, the catalyst prepared in this experiment can be easily recovered by magnetic separation technology in practical application, which will not affect the turbidity of water while reducing the cost of catalyst separation and recovery.

Conversion of cobalt from spent LIBs to Co3O4 electrode material for application in supercapacitors

ABSTRACT The cathode material of lithium-ion batteries (LIBs) is endowed with valuable metals, such as cobalt. The improper treatment of these batteries pollutes the environment and causes enormous resource waste. Therefore, the recovery of valuable metals from spent LIBs has attracted widespread attention. In this study, Co3O4 electrode materials were prepared by a simple homogeneous precipitation method and heat treatment using a leaching solution of spent LIBs-positive electrode material as the cobalt source. The crystal structure and morphology of the products were examined at different annealing temperatures, and their electrochemical performance was analyzed. The results show that low-temperature annealing contributes to grain refinement. The Co3O4 material prepared at 300°C annealing temperature has a rod-like structure with distinct pores and a specific surface area of 58.98 m2 g−1. Furthermore, electrochemical performance testing reveals that Co3O4 prepared at 300°C displays the best electrochemical performance as an electrode material, with a specific capacitance of 97.93 F g−1 and a cycle retention rate of 79.12% after 500 charge–discharge cycles. These findings demonstrate the feasibility of recycling valuable metal cobalt from spent LIBs cathode materials to produce Co3O4 materials for use as supercapacitor electrode materials, opening up new avenues for the recycling and utilisation of spent LIBs.

Growth Kinetics and Porous Structure of Surfactant-Promoted Gas Hydrate.

Surfactants present in tiny amounts in the aqueous phase are known to be efficient gas hydrate promoters; yet, the promotion mechanisms are still not fully understood. Understanding and directing those mechanisms is key to the implementation of gas-hydrate-based applications such as gas storage and separation, secondary refrigeration or water treatment, and desalination. In this work, the growth at the water/gas interface and the porous structure of surfactant-promoted methane hydrate are observed by optical microscopy and Raman imaging in glass capillaries used as optical cells. Hollow crystals are continuously generated and expelled from the methane/water meniscus into the water or surfactant solution, where they ultimately form the skeleton of a porous medium filled with the solution. Unprecedented information is gathered over a range of scales from the molecular scale (crystal structure and cage filling) to the mesoscale (crystal morphologies, growth habits and pore sizes) and macroscale (rates and amounts of water and gas converted into hydrate and hydrate porosity). Following an early steady-state growth regime, a sudden order-of-magnitude increase of the conversion rate occurs, which is related to gaseous methane microbubbles being directly incorporated across the meniscus in the aqueous solution and later converted to methane hydrate. An assessment and comparison are made of the mechanisms and performance of two common anionic surfactants known to be efficient gas hydrate promoters, SDS (sodium dodecyl sulfate) and AOT (dioctylsulfosuccinate sodium or AerosolOcTyl). AOT provides a quicker but more limited conversion into hydrate than SDS, suggesting that it is more appropriate for continuous flow processes while SDS is better suited for gas storage applications. Raman spectra reveal that cage filling by methane of structure I methane hydrate is not affected by surfactants.

Effect of TiO2 and CaO Addition on the Crystallization and Flexural Strength of Novel Leucite Glass-Ceramics.

The aim of this study was to investigate the effects of TiO2/CaO addition on the crystallization and flexural strength of leucite glass-ceramics (GC). Synthesis of translucent and high strength GCs is important for the development of aesthetic and durable dental restorations. To achieve this, experimental aluminosilicate glasses (1-3 mol% TiO2 and CaO (B1, B2, B3)) were melted in a furnace to produce glasses. Glasses were ball milled, screened and heat treated via crystallization heat treatments, and characterized using XRD, differential scanning calorimetry, dilatometry, SEM and biaxial flexural strength (BFS). Increasing nucleation hold time (1-3 h) led to a reduction in crystallite number for B2 and B3 GC, and significant differences in leucite crystal size at differing nucleation holds within and across test groups (p < 0.05). A high area fraction of leucite crystals (55.1-60.8%) was found in the GC, with no matrix microcracking. Changes in the crystal morphology were found with higher TiO2/CaO addition. Mean BFS of the GC were 211.2-234.8 MPa, with significantly higher Weibull modulus (m = 18.9) for B3 GC. Novel glass compositions enriched with TiO2/CaO led to crystallization of leucite GC of high aspect ratio, with high BFS and reliability. The study's findings suggest a potential high performance translucent leucite GC for use in the construction of dental restorations.

Chirality Determination of Nanocrystals by Electron Crystallography.

Chirality is a common phenomenon in nature and plays an important role in the properties of matter. The rational synthesis of chiral compounds and exploration of their applications in various fields require an unambiguous determination of their handedness. However, in many cases, determinations of the chiral crystal structure and chiral morphology have been a challenging task due to the lack of proper characterization methods, especially for nanosized crystals. Therefore, it is crucial to develop novel and efficient characterization methods. Owing to the strong interactions between matter and electrons, electron crystallography has become a powerful tool for structural analysis of nanomaterials. In recent years, methods based on electron crystallography, such as high-resolution electron microscopy imaging and electron diffraction, have been developed to unravel the chirality of nanomaterials. This brings new opportunities to the design, synthesis, and applications of versatile chiral nanomaterials. In this perspective, we summarize the recent methodology developments and ongoing research of electron crystallography for chiral structure and morphology determination of nanocrystals, including inorganic and organic materials, as well as highlight the potential and further improvement of these methods in the future.

Molecular Characterisation and Toxicity Analysis of Indigenous Bacillus thuringiensis Berliner Isolates against Cucurbit Fruit Fly Maggots, Zeugodacus cucurbitae (Coquilett) (Diptera: Tephritidae)

Background: Indiscriminate use of insecticides against fruit flies (Tephritidae: Diptera) has led to the development of residue and resistance and there is a need to try alternate eco-friendly management practices. Bacillus thuringiensis (Bt) is the most widely used bacterium forming proteins active against insects of different orders. Thus, the present study was framed to characterize and evaluate 50 indigenous Bt isolates against cucurbit fruit fly maggots, Zeugodacus cucurbitae. Methods: Colony morphology was observed visually, while crystal morphology was observed through a microscope. The cry gene content of the Bt isolates was screened by Polymerase Chain Reaction and the proteins harbored were assessed by SDS- PAGE analysis. Full diet contamination method was used to evaluate the toxicity of Bt isolates against cucurbit fruit fly maggots. Result: Uniform full white, off-white and creamy white colony colours were found except one isolate each, exhibiting full white at centre surrounded by off white and off white at centre surrounded by full white. Spherical shape crystal (45.10%) was predominant followed by cuboidal (29.41%), bipyramidal (17.65%), rectangular (3.92%) and minute crystal attached to spore (3.92%). Insecticidal proteins varied from ~15 to greater than 200kDa in size with one to four and more distinct bands per isolate. PCR screening revealed cry4Aa in 2 isolates, cry4Ba and cry11Aa in one isolate each, cyt1 in 1 isolate. The standard strain Bti 4Q2 (100% mortality of maggots) and the indigenous Bt isolates, T166 (92.59%), T184 (91.11%) and T60 (90.48%) were found to be significantly toxic.

Crystallization of Poly(ethylene terephthalate): A Review.

Poly(ethylene terephthalate) (PET) is a thermoplastic polyester with excellent thermal and mechanical properties, widely used in a variety of industrial fields. It is a semicrystalline polymer, and most of the industrial success of PET derives from its easily tunable crystallization kinetics, which allow users to produce the polymer with a high crystal fraction for applications that demand high thermomechanical resistance and barrier properties, or a fully amorphous polymer when high transparency of the product is needed. The main properties of the polymer are presented and discussed in this contribution, together with the literature data on the crystal structure and morphology of PET. This is followed by an in-depth analysis of its crystallization kinetics, including both primary crystal nucleation and crystal growth, as well as secondary crystallization. The effect of molar mass, catalyst residues, chain composition, and thermo-mechanical treatments on the crystallization kinetics, structure, and morphology of PET are also reviewed in this contribution.

Advancing crystal growth prediction: An adaptive kMC model spanning multiple regimes

Traditional batch crystallization processes encounter challenges like batch-to-batch variability, and difficulty in scale-up and achieving desired crystal size and morphology. These challenges stem from various growth mechanisms within crystallizers, influenced by operating conditions that dictate the dynamic surface structure of crystals. To overcome this, we developed a novel microscopic kinetic Monte Carlo model, which uses a specialized adsorption rate that adapts to different growth regimes by considering surface thermodynamic effects for different growth mechanisms. Specifically, the adaptive adsorption rate redefines the driving force of crystallization by considering the attachment energies of different adsorption sites (e.g., kink, adatom, and edge) and supersaturation. This approach enables seamless transitions across growth regimes. We use the lysozyme crystal system as a case study, demonstrating the model's superior predictive power in regime-to-regime transitions. Overall, the developed work provides a valuable new approach to understanding crystal morphology and predicting crystal growth rates in different growth regimes.

Effect of Additives on the Morphology of γ-Aminobutyric Acid Crystals.

The effect of surfactant, polymer, and tailor-made additives on the crystallization of γ-aminobutyric acid (GABA) was studied in this work. Cooling crystallization of GABA in water yielded plate-like crystals. In the presence of sodium stearate, polyhedral block-like crystals of GABA were obtained. Hydroxyethyl cellulose (HEC) led to rod-like crystals, in which the morphology was associated with additive concentrations. Six kinds of amino acids were used as tailor-made additives, and they exhibit different influences on crystal shape and size. The induction time of GABA was determined in the absence and presence of additives. The results showed that sodium stearate promoted nucleation, while HEC, l-Lysine, l-histidine, and l-tyrosine inhibited nucleation. Crystal face indexing, Hirshfeld surface analysis, and molecular dynamics (MD) simulation in aqueous solution-crystal systems were carried out to investigate the affecting factors of different crystal faces. The polymer additive was selected as an example during MD simulation to calculate intermolecular interactions between the crystal face and solvent or additive. The effect of the additive on the mobility of the solute in solution was also evaluated by mean-square displacement. The additive offers an effective approach for changing crystal morphology and particle size and adapting it to different production requirements.

Novel magnetic iron oxide-dextran sulphate nanocomposites as potential anticoagulants: Investigating interactions with blood components and assessing cytotoxicity

Examining the critical role of anticoagulants in medical practice, particularly their central function in preventing abnormal blood clotting, is of the utmost importance. However, the study of interactions between blood proteins and alternative anticoagulant nano-surfaces is still understood poorly. In this study, novel approach involving direct functionalisation of magnetic iron oxide nanoparticles (MNPs) as carriers with sulphated dextran (s-dext) is presented, with the aim of evaluating the potential of magnetically-responsive MNPs@s-dext as anticoagulants. The physicochemical characterisation of the synthesised MNPs@s-dext includes crystal structure analysis, morphology study, surface and electrokinetic properties, thermogravimetric analysis and magnetic properties` evaluation, which confirms the successful preparation of the nanocomposite with sulfonate groups. The anticoagulant potential of MNPs@s-dext was investigated using a standardised activated partial thromboplastin time (APTT) test and a modified APTT test with a quartz crystal microbalance with dissipation (QCM-D) which confirmed the anticoagulant effect. Time-resolved solid-liquid interactions between the MNPs@s-dext and model blood proteins bovine serum albumin and fibrinogen were also investigated, to gain insight into their hemocompatibility, and revealed protein-repellence of MNPs@s-dext against blood proteins. The study also addressed comprehensive cytotoxicity studies of prepared nanocomposites, and provided valuable insights into potential applicability of MNPs@s-dext as a promising magnetic anticoagulant in biomedical contexts.

Stepwise crystallization method combining isotactic polypropylene-based plastic waste film to prepare high-performance polypropylene random copolymer

Upcycling of waste plastic film is increasingly important at the background of energy shortage and environmental crisis. However, direct reuse of the waste plastics as reworked material inevitably downgrades the mechanical properties. Herein, a stepwise crystallization method was used to enable the recycling of waste isotactic polypropylene (iPP) film value-added in iPP-based homocomposites. In detail, the effect of β-nucleating agent (β-NA) and iPP on crystallization behaviors of polypropylene random copolymer (PPR) was investigated at first. The stepwise crystallization procedure was further introduced to promote the β-crystallization of PPR/iPP/β-NA composites in which the crystal structures, polymorph compositions and phase morphologies were systematically researched. At last, impact behaviors of PPR/iPP/β-NA composites were characterized and a penitential toughening mechanism was proposed. It was found that the stepwise crystallization boosted β-crystallization and growth of rubbery phase during the isothermal procedure, resulting in an increase of relative β-crystal content and low temperature impact toughness from 0 % and 2.02 kJ/m2 of neat PPR to 33.4 % and 3.06 kJ/m2 of PPR/iPP/β-NA composites. This work provides a simple, implementable, and effective method for the recycling of waste iPP films and the low-temperature toughening of PPR.

Oiling‐Out in Industrial Crystallization of Organic Small Molecules: Mechanisms, Characterization, Regulation, and Applications

AbstractOiling‐out is a common phenomenon in industrial crystallization processes that not only prolongs the total operating time but also leads to undesirable crystal morphology, making it challenging to control crystallization paths. This review provides a comprehensive overview of the oiling‐out phenomenon in organic small molecule crystallization. First, the formation mechanisms of oiling‐out are summarized from both thermodynamic and dynamic perspectives, providing the theoretical foundation for understanding the phenomenon. Then, the universal characterization methods for studying the oiling‐out phenomenon of organic small molecules are introduced in detail, covering both offline and online analytical tools. Moreover, the regulation strategy for oiling‐out, including solvents, impurities, seeding, temperature, and mixing methods are discussed. This paper also focuses on the application of oiling‐out in co‐assembly and crystal shape modulation. Finally, future opportunities and challenges are presented to address the current shortcomings and application bottlenecks in the study of organic small molecule oiling‐out phenomena. This review aims to provide valuable insights and guidance for researchers working on the crystallization of organic small molecules, particularly in the pharmaceutical industry, to better understand, control, and utilize the oiling‐out phenomenon.

Molecular dynamics simulation on crystal morphology of NH4ClO4.

Ammonium perchlorate (NH4ClO4, abbreviated as AP) has the advantages of high oxygen content, high density, and good compatibility, and has significant application prospects in the field of energetic materials. The crystal morphology has a great influence on the properties and sensibility of energetic materials, and a single experimental means is difficult in exploring the crystals; therefore, the crystal morphology of AP is investigated using molecular dynamics simulation complemented with experiments, to theoretically analyze the differences in AP crystal habit and the interactions between solvent molecules and the main growing crystal surfaces of AP. The results show that AP crystal is mainly composed of five independent crystal surfaces (0 0 1), (0 1 0), (1 0 0), (1 0 1), and (1 0 -1) in vacuum using the BFDH laws, with (0 0 1) surface being the main growth crystal surface. In contrast, in H2O solvent, the (1 0 1) and (1 0 -1) surfaces disappear, and the AP mainly consists of (0 0 1), (0 1 0), and (1 0 0) surfaces with a rectangular shape. The crystal morphology obtained from theoretical prediction is in good agreement with that obtained from experimental culture. This paper can provide a new idea for the cultivation and preparation of AP large crystals, and promote the application of AP crystals in energetic materials. The crystal morphologies of AP in vacuum and H2O solvent under Dreiding force field were predicted based on attachment energy model by using molecular dynamics method in Materials Studio 2019 software. The entire molecular dynamics simulation was carried out under the NTV system, the temperature control method was selected as Anderson, and the system temperature was set to 298 K. The simulation time was set to 40 ps, the step size was set to 1 fs, and the data were outputted every 5000 steps.

Chitosan/MgO NPs/CQDs bionanocomposite coating: Fabrication, characterization and determination of antimicrobial efficacy

The development of new polymer nanocomposites or antibacterial coatings is crucial in combating drug-resistant infections, particularly bacterial infections. In this study, a new chitosan polymer based nanocomposite reinforced with magnesium oxide nanopowders and carbon quantum dots was fabricated by sol-gel technique and coated on 316 L stainless steel. In order to gaining the optimal amount of components to achieve the maximum antibacterial properties, the effect of concentration of nanocomposite components on its antibacterial properties was investigated. Crystal structure, microstructure, elemental dispersion, size distribution, chemical composition and morphology of nanocomposite and coating were characterized with various analyses. The obtained results exhibited that the carbon quantum dot and magnesium oxide nanopowders were distributed uniformly and without agglomeration in the chitosan matrix and created a uniform coating. The antibacterial properties of the synthesized samples against Staphylococcus aureus bacteria (gram positive) were evaluated using disk diffusion and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) antibacterial tests. The inhibition growth zone formed around the antibiotic and nanocomposite 25 mg/ml under dark and light was about 32 and 14, 11 mm, respectively. Also, MIC and MBC values for final nanocomposite were 62.5 and 125 μg/ml, respectively.

Synthesis and luminescence properties of color-tunable BaLaGa3O7: Bi3+,Sm3+ phosphors

We prepared BaLaGa3O7: Bi3+,Sm3+ phosphors via solid state reactions and investigated their crystallinity, lattice occupancy, and photoluminescence performance. The phase and crystal structure, morphology and size, as well as element composition of phosphor were investigated via a series of measurements. The photoluminescence and Bi3+ → Sm3+ energy transfers were investigated in detail. It is proved that Bi3+ → Sm3+ energy transfer occurs in Bi3+/Sm3+ codoped BaLaGa3O7 phosphors and it is induced by dipole–dipole interaction. By calculating the decay lifetime, the efficiency of Bi3+ → Sm3+ energy transfer is evaluated. The CIE coordinates of the prepared show obvious dependence on Sm3+ concentration and temperature.

The Influence of Varying Ar/O2 Gas Ratio with Catalyst-Free Growth by Homemade Thermal Evaporation Technique

A nanostructured zinc oxide (ZnO) with different percentages of argon and oxygen gas flow rate was deposited on a silicon wafer by a simple hot tube thermal evaporation technique. The effect of different percentages of gas flow rate on the crystal structure, surface morphology and optical properties were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and RAMAN spectroscopy, respectively. The changes of morphologies from FESEM were significant where the grown ZnO nanostructures show three different shapes which are nanotripods, nanoclusters and nanorods at 5%, 10% and 25% of oxygen gas, respectively. EDX results revealed that Zn and O elements have a major percentage in the sample indicating a composition has high purity of ZnO. XRD patterns displayed the most intense diffraction peak of ZnO at (101), which exhibited a single crystalline hexagonal structure with preferred growth orientation in the c-axis. RAMAN scattering study found that synthesized ZnO shows the high intensity of E2 mode and low intensity of E1 mode attributed to all the samples having good crystal quality containing fewer structural defects. In conclusion, the E15 sample with a 25% oxygen gas flow rate was selected as an optimum result for synthesizing a homogenous surface and high crystallinity of ZnO by using a hot tube thermal evaporation process. This work can enhance the development of ZnO production in various applications.

Perovskites synthesized by soft template-assisted hydrothermal method: A bibliometric analysis and new insights

Hydrothermal synthesis is a technique which enables preparing many perovskites with specific crystal structures, chemical compositions, and morphologies. Thus, a bibliometric analysis of 1087 articles from the Scopus database (1975–2023) related to the keywords “perovskites” and “hydrothermal synthesis” was conducted using the VOSviewer software program. The results of the bibliometric analysis showed that the 1087 articles have 23,286 citations. Materials Letters has the highest number of publications (2.85%) regarding the journals in which these articles are published. China has the highest number of publications (34.50%) and citations (33.56%) related to these articles. Regarding the institutions affiliated with these articles, Jilin University in China concentrates 5.34% of the publications and 6.08% of the citations. In terms of authors, Han, G. has the highest number of publications (2.02%). Finally, the top three keywords with the highest number of occurrences were “perovskite”, “hydrothermal synthesis” and “scanning electron microscopy”. Based on bibliometric analysis, LaNiO3 perovskites were chosen to evaluate the influence of hydrothermal synthesis parameters on their morphologies and, consequently, how these morphologies affect their applications. Thus, the temperature and time ranges used for the synthesis parameters were 160–230 °C and 6–48 h, respectively. Furthermore, the pH range used was 7.6–13, and the mineralizers used to adjust the pH were ammonia, potassium hydroxide, and sodium hydroxide. The temperature and time ranges used for the calcination parameters were 550–800 °C and 2–6 h, respectively. Additionally, LaNiO3 perovskites obtained sphere, cube, rod, disc, and hollow morphologies. The soft templates used to obtain these morphologies were glycine, glycerin, isopropanol, polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), citric acid, and urea. The specific surface areas of the perovskites varied between 5.2 and 35.8 m2 g−1. Finally, the most common application for LaNiO3 perovskites was the methane reforming for hydrogen production.