Nucleation Free Energy Research Articles

Rate theory of gas-liquid nucleation: Quest for the elusive quantitative accuracy.

The task of a first principles theoretical calculation of the rate of gas-liquid nucleation has remained largely incomplete despite the existence of reliable results from unbiased simulation studies at large supersaturation. Although the classical nucleation theory formulated by Becker-Doring-Zeldovich about a century ago provides an elegant, widely used picture of nucleation in a first-order phase transition, the theory finds difficulties in predicting the rate accurately, especially in the case of gas-to-liquid nucleation. Here, we use a multiple-order parameter description to construct the nucleation free energy surface needed to calculate the nucleation rate. A multidimensional non-Markovian (MDNM) rate theory formulation that generalizes Langer's well-known nucleation theory by using the Grote-Hynes MDNM treatment is used to obtain the rate of barrier crossing. We find good agreement of the theory with the rate obtained by direct unbiased molecular dynamics simulations-the latter is feasible at large supersaturation, S. The theory gives an experimentally strong dependence of the rate of nucleation on supersaturation, S. Interestingly, we find a strong influence of the frequency-dependent friction coefficient at the barrier top. This arises from multiple recrossings of the barrier surface. We find that a Markovian theory, such as Langer's formulation, fails to capture the rate quantitatively. In addition, the multidimensional transition state theory expression performs poorly, revealing the underlying role of the friction coefficient.

Insights into the crystallization behavior of structurally and spatially doubly confined polymer systems studied by molecular simulation

The impact of grafting density and polymer-substrate interactions on the crystallization behavior of structurally and spatially doubly confined polymer systems was studied using Monte Carlo simulation methods. In the confined polymer system with low grafting density, as the polymer-substrate interactions increase, the nucleation mode shifts from homogeneous nucleation to heterogeneous nucleation. The melting temperature and undercooling increase, while the critical nucleation free energy barrier decreases, favoring the crystallization process. Nevertheless, significant polymer-substrate interactions can lead to a decrease in the mobility of polymer chains, thereby inhibiting the crystallization process. In highly grafted polymer systems, homogeneous nucleation controls the entire crystallization process and the crystallization rate and final degree of crystallinity are almost unaffected by polymer-substrate interactions. Grafting density and polymer-substrate interactions play a dual role, acting as a “double-edged sword” in the crystallization process of doubly confined polymer systems. An appropriate grafting density and polymer-substrate interactions facilitate the nucleation ability, thereby promoting the crystallization capability of polymer systems. Conversely, excessive interactions can weaken nucleation ability and suppress crystal growth.

Cryopreservation of human semen by inherently-controlled icing probability: Or how the surface profile of superhydrophobic carbon soot coatings and the sperm volume affect the outcome of slow freezing?

The restoration of initial functionality of human spermatozoa subjected to cryopreservation is challenging, because the deleterious intracellular icing and the occurrence of osmotic shocks due to prolonged exposure to increased concentrations of intracellular solutes are oppositely dependent on the cooling rate. This longstanding problem could be overcome if using superhydrophobic soot coatings delaying the heat transfer rate, reducing the ice formation probability and triggering balanced and timely dehydration of the cells, but the effect of their surface profile and sperm volume on the success rate of slow freezing is unclear. Here, we show for the first time that the two-factor freezing injury is entirely avoidable by tailoring the solid-to-gas voids (pores) fraction in the soot, leading to increased nucleation free energy barrier, presumable incipiency of ice crystals with controllable shape and size and hence, fully (100 %) recovered post-thaw sperm motility. It is demonstrated that the reason for such a unique scientific result is the selection of soot coatings with appropriate morphochemical features, hypothetically (not directly proven yet) inducing equilibrium among the solution composition and ice crystals formation, retarding the undesirable compression of liquid-filled “slush ice” channels surrounding the cytoplasm and impeding the ice recrystallization. The novel insights introduced in this article open endless horizon for customizing and revolutionizing the technical protocols in cryobiology.

Comparing brute force to transition path sampling for gas hydrate nucleation with a flat interface: comments on time reversal symmetry.

Fluid to solid nucleation is often investigated with the rare event method transition path sampling (TPS). I claim that the inherent irreversibility of solid nucleation, even at stationary conditions, calls into question TPS's applicability for determining solid nucleation mechanisms, especially for pre-critical behavior. Even when applied to a phenomenon which displays time reversal asymmetry like solid nucleation, TPS is a good means of exploring phase space and giving trends in post-critical structure, and its ability to facilitate nucleation rate and free energy calculations remains outstanding. Forward-only splitting and ratcheting methods such as forward flux sampling are more attractive for understanding nucleation mechanisms as they do not require time reversal symmetry, but at low driving forces may suffer from the same limitations as brute force: they may never make it to the first ratchet. Here I briefly summarize the TPS method and gas hydrate nucleation simulation literature, focusing on topics within both to facilitate a comparison of brute force hydrate nucleation to transition path sampling of hydrate nucleation. Perhaps anecdotally, the brute force technique results in more crystalline trajectories despite having higher driving forces than TPS. I maintain this difference is because of the inherent irreversibility of hydrate nucleation, meaning its pre-critical behavior cannot accurately be determined by the melting trajectories that comprise approximately half of the configurations in TPS's path ensemble.

Size-Independent Nucleation and Growth Model of Potassium Sulfate from Supersaturated Solution Produced by Stirred Crystallization.

This paper explores the kinetics of the crystallization of potassium sulfate in a stirred bed crystallizer through experimental investigation. Employing classical nucleation theory, the homogeneous and heterogeneous nucleation mechanisms of potassium sulfate were investigated. The induction time and critical nucleation parameters, including the surface tension (γ), critical nucleation radius (r*), critical nucleation free energy (ΔG*), and critical nucleation molecule number (i*), were meticulously determined under varying temperatures and supersaturation ratios. The experimental findings revealed that as the temperature and supersaturation ratio increased, the induction time, critical nucleation free energy, critical nucleation radius, and critical molecule number decreased whereas the nucleation rate increased. The crystalline shape remains relatively unaltered with respect to temperature and supersaturation ratio, yet the particle size (D10, D50, D90) increases as the supersaturation and temperature increase. The variations in the measured nucleation parameters align well with the predictions of classical nucleation theory. Furthermore, the kinetic equations of crystal nucleation and the growth rate in a stirred crystallization system were fitted using population balance equations. The results demonstrate that the growth rate increases with increasing supersaturation and stirring rates. Additionally, the effects of the parameters in the nucleation rate equation suggested that the suspension density exerted the greatest influence, followed by the supersaturation ratio and stirring rate. This extensive research provides invaluable theoretical guidance for optimizing the crystallization process and designing industrial crystallizers.

Direct evidence on the crossover from BCC to FCC stability: A lattice-based aggregation-volume-bias Monte Carlo approach to polymorphism.

A lattice-based version of the aggregation-volume-bias Monte Carlo method that was introduced recently has allowed for the extension of the calculation of the nucleation free energies from liquid clusters to solid clusters. Here, it was used to calculate the nucleation free energies of both bcc and fcc clusters formed by Lennard-Jones particles. Under the simulation conditions considered in this study, a cross-over of the thermodynamic stability from the bcc to the fcc structure was observed directly from the free energy results. In addition, the free energies obtained for both types of clusters were used to extrapolate bulk phase information, including chemical potential and surface tension, which revealed that bcc clusters are favored due to the lower surface tension. These results corroborate a recent classical density functional theory study. This work also demonstrates that this approach can be used to predict the entire thermodynamic landscape (i.e., free energies for clusters of different structures and sizes, including an infinitely large cluster, which is the bulk phase), which is important to answer fundamental questions related to crystallization such as the origin of polymorphism.

Large‐scale synthesis of CuS nanoparticles for photothermal materials using high‐concentration Cu complex ion precursor

AbstractCopper sulfide (CuS), a copper‐deficient p‐type semiconductor material, has been widely utilized due to its unique optical properties, low toxicity, and cost‐effectiveness. Although many studies have been conducted on synthesizing CuS nanoparticles, harsh synthetic conditions and low yield must be solved. This study presents a new methodology that can synthesize CuS nanoparticles in large quantities at room temperature and pressure using high‐concentration Cu complex ion precursors. This methodology is based on the theory that the critical nucleus radius and the critical nucleation free energy decrease as the concentration of the precursor increases to synthesize a large number of nanoparticles by applying low energy. In addition, it is possible to minimize the aggregation of nanoparticles, which is a problem of nanoparticles synthesized at a high precursor concentration through complex ions in the solution. We synthesized nanoparticles by controlling the precursor concentration from 0.1 to 2.5 M to confirm the effect of the precursor concentration on the size, shape, and yield of nanoparticles. As the precursor concentration increased, the particle size decreased, and the yield improved. The CuS nanoparticles synthesized at the highest concentration had a size of about 17 nm without a strong agglomeration and a yield of about 213.9 g/L. Furthermore, the nanoparticles showed excellent photothermal performance due to their high near‐infrared absorption. When about 0.1 g of the nanoparticles were irradiated with a Xenon lamp and an 808 nm laser, the maximum temperatures and rising rates were 53.7°C and 172.1°C and 13.8°C/mg and 33°C/mg, respectively. The excellent photothermal properties of CuS nanoparticles suggest the potential of this material for various applications.

Are Neural Network Potentials Trained on Liquid States Transferable to Crystal Nucleation? A Test on Ice Nucleation in the mW Water Model.

Neural network potentials (NNPs) are increasingly being used to study processes that happen on long time scales. A typical example is crystal nucleation, which rate is controlled by the occurrence of a rare fluctuation, i.e., the appearance of the critical nucleus. Because the properties of this nucleus are far from those of the bulk crystal, it is yet unclear whether NN potentials trained on equilibrium liquid states can accurately describe nucleation processes. So far, nucleation studies on NNPs have been limited to ab initio models whose nucleation properties are unknown, preventing an accurate comparison. Here we train a NN potential on the mW model of water─a classical three-body potential whose nucleation time scale is accessible in standard simulations. We show that a NNP trained only on a small number of liquid state points can reproduce with great accuracy the nucleation rates and free energy barriers of the original model, computed from both spontaneous and biased trajectories, strongly supporting the use of NNPs to study nucleation events.

Nucleation of Biomolecular Condensates from Finite-Sized Simulations.

The nucleation of protein condensates is a concentration-driven process of assembly. When modeled in the canonical ensemble, condensation is affected by finite-size effects. Here, we present a general and efficient route for obtaining ensemble properties of protein condensates in the macroscopic limit from finite-sized nucleation simulations. The approach is based on a theoretical description of droplet nucleation in the canonical ensemble and enables estimation of thermodynamic and kinetic parameters, such as the macroscopic equilibrium density of the dilute protein phase, the surface tension of the condensates, and nucleation free energy barriers. We apply the method to coarse-grained simulations of NDDX4 and FUS-LC, two phase-separating disordered proteins with different physicochemical characteristics. Our results show that NDDX4 condensate droplets, characterized by lower surface tension, higher solubility, and faster monomer exchange dynamics compared to those of FUS-LC, form with negligible nucleation barriers. In contrast, FUS-LC condensates form via an activated process over a wide range of concentrations.

Experimental Investigation of p-Xylene Crystallization Characteristics and Ultrasound Enhancement Mechanism

Para-xylene (PX) is one of the most crucial aromatic raw materials in petrochemical industry. It is urgent to develop a more low-cost and efficient PX production process due to the growing demand for PX. This paper introduces ultrasound into the PX crystallization process and analyzes the data of supersolubility, metastable zone width, and induction period of PX under different working conditions. Based on the classical nucleation theory and the cluster coalescence model, the PX crystallization characteristics and the mechanism of ultrasound enhancement are investigated. The results can be concluded as follows. Ultrasound significantly reduces the metastable zone width and induction period of the PX crystallization process, speeds up the crystal nucleation rate, and prevents the explosion nucleation. When the supersaturation is above 1.055, the PX nucleation mechanism is homogeneous nucleation, and when it is below 1.055, the PX nucleation mechanism is heterogeneous nucleation. The crystal growth mechanism is continuous growth. The PX-dominated cluster at the mesoscale contains 14 monomers. The formation period of clusters is accelerated by ultrasound, and the critical nucleation radius and critical nucleation free energy of PX are both dramatically decreased. The system’s diffusion coefficient is improved by ultrasound, which also lowers the interfacial tension and the surface entropy factor corresponding to the two nucleation mechanisms. When the ultrasonic power changes from 0 to 88 W, the crystal nucleation rate constant increases by 22.4 times and the diffusion coefficient by 11.86 times. Theoretically, this study might enable future PX crystallization process improvements.

Nucleation and crystallization mechanism of heavy hydrocarbons in natural gas under flow field

The understanding of the crystallization mechanism of heavy hydrocarbons in natural gas directly determines the modification of nucleation theory and the development of new liquefaction processes. However, the mechanism of heavy hydrocarbon crystallization in the flow field is still not well understood. In this paper, molecular dynamics (MD) simulations were adopted to investigate heavy hydrocarbon crystallization under shear flow, and the nucleation pathway related to crystallization kinetics was explored. The results show that shear rates less than 1 × 108 s−1 promote the rapid growth of heavy hydrocarbon crystals with high final crystallinity, whereas higher shear rates cause crystals to grow slowly ending up with lower crystallinity. Compared with quiescent nucleation, the presence of a shear flow promotes the heavy hydrocarbon stretching and consequently accelerates the kinetic process of phase transition. In addition, molecular orientation fluctuations arising from the flow field are accompanied by the elastic deformation of solid nucleus, increasing the nucleation free energy barrier. Therefore, the nucleation rate of heavy hydrocarbon liquids peaks at the optimal shear rate 1 × 107 s−1. Moreover, a unified pathway for heavy hydrocarbon nucleation under shear flow was proposed.

Interfacial charge transfers and ultrafast nonlinear optical response via constructing electronic structure-induced MoS2/ZnO heterostructure

The molybdenum disulfide (MoS 2 ) and ZnO composite system have reported as micro-nano photonic crystals in integrated optics. Based on interface engineering, their tunable nonlinear absorption (NLA) and photoelectric characteristics offer a flexible design strategies for saturation absorber and optical limiters. Nevertheless, the mechanism leading to the tunable NLA behavior has not been clearly elucidated, which were attribute to complex charge transfers and carrier regulation characteristics. In this article, MoS 2 /ZnO heterostructures with excellent nonlinear properties composed of ZnO nanorods (NRs) wrapped with MoS 2 nanosheets were prepared by magnetron sputtering (MS) synthesis of MoS 2 on highly stacked ZnO NRs. The MoS 2 /ZnO heterostructures exhibit an interesting brush-like morphology with abundant heterointerfaces base on optimizing sputtering time and temperature, which was beneficial to provide efficient charge transfer pathways. Due to the uneven distribution of the lowest nucleation free energy, MoS 2 nanosheets possess a hybrid mode of parallel (C // ) and perpendicular orientations (C ┴ ) on surface of ZnO NRs, which tends to form the bending and vertical growth of layered MoS 2 nanosheets. From electron-photon coupling effect, MoS 2 nanosheets, ZnO NRs and MoS 2 /ZnO heterostructures possess favorable saturation absorption (SA), reverse saturation absorption (RSA) and coexisting absorption behavior, respectively. In addition, a changeover from RSA to SA could be realized in MoS 2 /ZnO heterostructures by increasing the sputtering time. The NLA coefficient of MoS 2 /ZnO heterostructures are in the order of 10 −10 cm/W, which are about 2 times larger than those of the ZnO NRs. Thus, the MoS 2 /ZnO heterostructures with excellent NLA properties will be promising candidates in optoelectronic devices. • The interfacial charge transfers and carrier regulation characteristics of MoS 2 /ZnO composite have been studied. • The ultrafast nonlinear optical properties of MoS 2 /ZnO composite were analyzed. • The mechanism of growth and nonlinear absorption for MoS 2 /ZnO composite is analyzed.

Can solid surface energy be a predictor of ice nucleation ability?

Surface energy is one of the most important properties of materials that dictate many behaviors such as the spreading of water and ice nucleation. It is commonly thought that low surface energy leads to hydrophobicity and delays ice formation. Conventional studies mainly focus on rough surfaces where surface energy is amplified/reduced accordingly and it remains elusive to clearly decouple the effect of surface energy on ice nucleation. Here we experimentally construct the atomically smooth surfaces of halogen chemistry by varying silane self-assembled monolayers with exactly the same aliphatic chain but varied end groups of F, Cl, Br and I. By analyzing ice nucleation rate and free energy barrier based on the measured freezing temperature/delay time and the classical nucleation theory, we demonstrate that the ice nucleation efficiencies of various halogen chemistry surfaces increase in the order of Br, F, I and Cl, which is inconsistent with the surface energy sequence. The results indicate that solid surface energy is not a secure predictor of ice nucleation ability. By further analyzing the surface potentials of different halogen chemistry surfaces, we find that surface polarity plays a key role in ice nucleation maybe through impacting the orientation of interfacial water.

Influence of hydrogen and helium nucleation on the mechanical properties of beryllium by first-principles calculations

A systematic investigation has been conducted to clearly elucidate the physical pictures of H, He, and hybrid bubbles nucleation and their effects on the mechanical properties of beryllium for the application in extreme environment. The simulation is carried out by first-principles calculations based on the density functional theory as implemented in VASP. The change of the configurational entropy has been considered throughout the simulation. In the nucleation of H bubble H m -2V B e along the direction of 〈 0001 〉 , the structures of a triangle and a tetragon in the plane of ( 11 2 ̄ 0 ), a hexahedron and two symmetrically distributed hexahedron have been successively observed as more H atoms are captured. The deformation degree increases with the increase of number of H atoms. For the nucleation of He bubble He n -2V B e along the direction of 〈 1 ̄ 102 〉 , the structures of an isosceles triangle in the plane of ( 11 2 ̄ 0 ), an octahedron and a regular polyhedron have also been observed as more and more He atoms are captured. The total nucleation free energy change always remains negative when fifteen He atoms are captured due to the production of new vacancies induced by self-trapping mechanism. The degree of distortion is more serious compared with that induced by H atoms. For the nucleation of hybrid bubble, the separate nucleation of H and He bubbles begin to interact with each other by exchanging atoms with the trapping of eight He atoms. The influence of retained H and He atoms on the mechanical properties of bulk Be has been characterized by first-principles uniaxial tensile test and the essence of weakening effect has been elucidated by charge density. The Young’s modulus of pure Be is consistent with experimental result. Both the nucleation of H, He, and hybrid bubbles could cause the reduction of the Young’s modulus and the tensile strength of Be. The degradation induced by He bubble is more severe than that of H bubble. • Some interesting structures are observed during the nucleation of H/He bubbles. • The configurational entropy is considered to estimate the nucleation of bubbles. • New vacancies are induced by the self-trapping mechanism. • The effect of bubbles nucleation on the mechanical properties of Be is elucidated.

Influences of Oxidation Degree and Size on the Ice Nucleation Efficiency of Graphene Oxide.

Figuring out the influences of carbonaceous particle properties on ice nucleation is important to atmospheric science, but it is still a challenge, especially for experimental investigations due to the coupling effect of multiple properties. Here we separately investigate the effects of oxidation degree and size, two typical and debated factors, on ice nucleation efficiency by choosing graphene oxide (GO) as the model. The results show that with the decrease of oxidation degree, ice nucleation efficiency increases through decreasing the ice nucleation free energy barrier () on GO surface. Interestingly, although the chosen GO sizes are sufficiently large compared with the sizes of critical ice nuclei, the increase of GO size leads to the increase of and thus the decrease of ice nucleation efficiency, unlike the general thought that is not affected by the particle size any more when the size of particle increases to several times that of the critical ice nucleus.

Solidification characteristic enhancement of aqueous nanofluid with different carbon nanotube sizes

In this work, the solidification characteristic of aqueous carbon nanotubes (CNTs) nanofluids with various CNTs sizes and concentrations were experimentally investigated. It is indicated addition of surfactant sodium dodecyl benzene sulfonate (SDBS) keeps suspension stability of CNTs nanofluid after solidification-melt cycle, and shows a positive effect during the nucleation region. The results show that subcooling degree and energy storage duration decrease as increasing CNTs concentration from 50 ppm to 2000 ppm. Furthermore, it is found the size of CNTs has a great influence on solidification characteristics. The subcooling degree depression and storage energy acceleration for aqueous nanofluids are more effective as the smaller diameter and longer length of CNTs. A maximum reduction of 47.3% in subcooling degree and 17.8% in charging speed advance were achieved for the CNTs nanofluid with diameter of <8 nm and length of 10–30 um at 500 ppm compared to the deionized water. Moreover, nucleation free energy for five sizes of nanofluids was studied by heterogeneous nucleation in consideration of contact angle and radius of CNTs. The results show the lower nucleation free energy is relevant to the lower subcooling.

Key Factors Governing Initial Stages of Lipid Droplet Formation.

Lipid droplets (LDs) are neutral lipid storage organelles surrounded by a phospholipid (PL) monolayer. LD biogenesis from the endoplasmic reticulum is driven by phase separation of neutral lipids, overcoming surface tension and membrane deformation. However, the core biophysics of the initial steps of LD formation remains relatively poorly understood. Here, we use a tunable, phenomenological coarse-grained model to study triacylglycerol (TG) nucleation in a bilayer membrane. We show that PL rigidity has a strong influence on TG lensing and membrane remodeling: when membrane rigidity increases, TG clusters remain more planar with high anisotropy but a minor degree of phase nucleation. This finding is confirmed by advanced sampling simulations that calculate nucleation free energy as a function of the degree of nucleation and anisotropy. We also show that asymmetric tension, controlled by the number of PL molecules on each membrane leaflet, determines the budding direction. A TG lens buds in the direction of the monolayer containing excess PL molecules to allow for better PL coverage of TG, consistent with the reported experiments. Finally, two governing mechanisms of the LD growth, Ostwald ripening and merging, are observed. Taken together, this study characterizes the interplay between two thermodynamic quantities during the initial LD phases, the TG bulk free energy and membrane remodeling energy.

Rapid preparation of low thermal expansion transparent LAS nanocrystalline glass by one-step thermoelectric treatment

The Li2O–Al2O3–SiO2 (LAS) glass ceramics are prepared by one-step thermoelectric treatment. The influence of thermoelectric treatments on LAS glass-ceramics were studied. The crystal phase composition and microstructure of the LAS glass-ceramics were investigated by DSC, SEM, XRD and FTIR. Moreover, the thermal expansion performance and light transmittance of LAS nanocrystalline glass were characterized. The results show that low-expansion transparent LAS nanocrystalline glass can be produced in a short time by thermoelectric treatment. The free energy of nucleation and the degree of polymerization of the glass network are reduced by the electric field. The key is that the electric field polarizes Ti and Zr ions at the crystallization temperature, so that the crystal nuclei repel the same poles. This allows uniform crystal distribution, promotes crystallization and reduces one-step crystallization of crystal agglomeration. This proves that the rapid preparation of nanocrystalline glass by the one-step method is feasible, and provides a reference for the future one-step processing of glass-ceramics.

Introducing PbSe quantum dots and manipulating lattice strain contributing to high thermoelectric performance in polycrystalline SnSe

Here, a p-type polycrystalline SnSe integrated with PbSe quantum dots is fabricated by an in situ magnetic field-assisted hydrothermal route. The decrease of the critical nucleation free energy and increase of homogeneous nucleation rate lead to the formation of PbSe quantum dots under high magnetic field. The enhanced density of states due to PbSe quantum dots causes significantly enhanced Seebeck coefficients and power factor. A large integral area of power factor over the full temperature range is optimized. The lattice strain induced by dislocations and stacking faults shortens the phonon relaxation time, leading to an ultralow lattice thermal conductivity (0.32 W m−1 K−1 at 873 K perpendicular to the pressing direction). Consequently, these electronic and thermal effects contribute to a high ZT of ∼1.9 at 873 K and an outstanding average ZT of 0.71 in polycrystalline SnSe. The combination of introducing PbSe quantum dots functional units and manipulating lattice strain provides a new perspective for designing high performance thermoelectric devices.

A facile organic-free synthesis of high silica zeolite Y with small crystal in the presence of Co2+

The direct synthesis of zeolite Y with high SiO 2 /Al 2 O 3 (SAR > 6.0) and small crystal size is a great challenge. The conventional production of high silica Y usually involves organic template into the synthesis system, which takes high cost. Here, zeolite Y with SAR of 6.15 and small crystal size via introducing Co 2+ in a facile one-step hydrothermal method without organic template was achieved. The SAR increased from 5.2 to 6.15 compared to normal NaY, and the crystal size decreased to 50%. The introduction of Co 2+ in synthesis system affects the formation of 5-coordination intermediate ( M-O -Si )* around Co 2+ during crystallization process which is the critical factor to nucleation. The stability of ( Co–O –Si )* is weaker than that of ( Al–O –Si )*, which leads to the increase of SAR around Co 2+ . The microcrystals of Co(OH) 2 provide adhesive surface for the amorphous material and promote nucleation. The zeolite Y shows good performance in the cracking of 1,3,5-triisopropylbenzene because of larger surface area and more active sites being exposed. This is a new strategy for industrial synthesis of high SiO 2 /Al 2 O 3 and small crystal size zeolite Y. • Zeolite Y with SiO 2 /Al 2 O 3 of 6.15 and small crystal size was achieved by introducing Co 2+ in a facile hydrothermal method. • The nucleation free energy was reduced by the microcrystalline Co(OH) 2 species via adhering to the amorphous materials. • The ΔG of (Co-O-Si)* is higher than that of (Al-O-Si)*, Si species combine with (Al-O-Si)* to increase the SiO 2 /Al 2 O 3 .