One-step Molten Salt Method Research Articles

One-Step Molten Salt Method For Synthesis of Perovskite-Like Sr2Nb2O7 and Sr5Nb4O15 Ceramics

Abstract In this study, Sr2Nb2O7 and Sr5Nb4O15 layered perovskite-like ceramics were synthesized by a single process using a one-step molten salt method. By optimizing the key parameters, including the choice of molten salt, reaction temperature and residence time, two materials achieve synchronous production. The crystal structures of the synthesized materials were confirmed by X-ray diffraction. It is proved that it has typical perovskite-like structural characteristics. Scanning electron microscopy reveals the morphology of these materials. Sr2Nb2O7 presents a sheet-based structure, and Sr5Nb4O15 presents a rod-based structure. This study provides an efficient and direct method for the synthesis of perovskite materials. One-step molten salt method has great potential in the synthesis of multiphase materials. These findings are expected to promote the application of perovskite materials in the fields of electronics, optics and catalysis.

LaMn-doped cobalt spinel catalysts for enhanced oxygen evolution performance in acidic media

While cobalt-based oxides can function as OER catalysts under acidic conditions, challenges such as high overpotential and inadequate stability persist, demanding solutions to fulfill practical application demands. We utilized a rapid and efficient one-step molten salt method to synthesize LaMn-doped Co3O4 supported on carbon cloth, with the aim of improving its OER activity and stability in acidic conditions. Subsequent characterization revealed that doping increased oxygen vacancies and lattice distortion within the spinel structure, while also altering the morphology of the catalyst surface, rendering it denser. In addition, the doping optimizes the electronic structure around cobalt, so that the electrons around oxygen are biased towards cobalt, which enhances the electrocatalytic activity of Co3O4 and the stability of Co–O bonds. Ultimately, under 0.5 M H2SO4 conditions, LaMn–Co3O4/CC exhibited superior OER activity and stability, displaying a lower overpotential of 370 mV at a current density of 10 mA cm−2 and maintaining stability for over 24 h, a notable enhancement compared to pure Co3O4.

Enhancing ionic conductivity and controlling lithium dendrite growth via ferroelectric ceramic Bi4Ti3O12

BackgroundSolid polymer electrolytes (SPEs) have gained numerous research interest in the field of lithium metal batteries. Solid polymer electrolytes have improved safety compared to liquid electrolytes. Despite this, their low ionic conductivity remains a major barrier to practical applications. To overcome the challenge of low ionic conductivity in SPEs, our study introduces a novel approach that integrates ferroelectric ceramics with polymer solid electrolytes. MethodsWe used a one-step molten salt method to synthesize Bi4Ti3O12 (BIT), combined with a poly (vinylidene difluoride) matrix to form the composite solid-state electrolyte. Through various electrochemical characterizations and COMSOL Multiphysics simulations, we discovered that the ferroelectric properties of BIT significantly increase the dissociation of lithium salts, leading to a greater concentration of mobile lithium ions and more efficient ion transport. Significant findingsThis electrolyte showed a remarkable improvement in lithium-ion conductivity, reaching a value of 8.5 × 10−4 S cm−1 at room temperature. Batteries made with these composite electrolytes demonstrate superior cycling stability, the capacity retention rates for LFP/SPEs/Li cells remain high, reaching 95 % even after 1,000 cycles at room temperature (25 °C). These findings highlight the promising applications of ferroelectric ceramics in solid-state batteries.

Effect of multi-interface electron transfer on water splitting and an innovative electrolytic cell for synergistic hydrogen production and degradation

The cleaning and utilization of industry wastewater are still a big challenge. In this work, we mainly investigate the effect of electron transfer among multi-interfaces on water electrolysis reaction. Typically, the CoS2, Co3S4/CoS2 (designated as CS4-2) and Co3S4/Co9S8/CoS2 (designated as CS4-8-2) samples are prepared on a large scale by one-step molten salt method. It is found that because of the different work functions (designated as WF; WF(Co3S4) = 4.48eV, WF(CoS2) = 4.41eV, WF(Co9S8) = 4.18 eV), the effective heterojunctions at the multi-interfaces of CS4-8-2 sample, which obviously improve interface charge transfer. Thus, the CS4-8-2 sample shows an excellent oxygen evolution reaction (OER) activity (134 mV/10 mA cm−2, 40 mV dec−1). The larger double-layer capacitance (Cdl = 17.1 mF cm−2) of the CS4-8-2 sample indicates more electrochemical active sites, compared to the CoS2 and CS4-2 samples. Density functional theory (DFT) calculation proves that due to interface polarization under electric field, the multi-interfaces effectively promote electron transfer and regulate electron structure, thus promoting the adsorption of OH− and dissociation of H2O. Moreover, an innovative norfloxacin (NFX) electrolytic cell (EC) is developed through introducing NFX into the electrolyte, in which efficient NFX degradation and hydrogen production are synergistically achieved. To reach 50 mA cm−2, the required cell voltage of NFX-EC has decreased by 35.2%, compared to conventional KOH-EC. After 2h running at 1 V, 25.5% NFX was degraded in the NFX EC. This innovative NFX-EC is highly energy-efficient, which is promising for the synergistic cleaning and utilization of industry wastewater.

One-step molten salt synthesis of high entropy oxides

High-entropy oxides (HEOs) have received widespread attention owing to their tunable properties and vast composition spaces. However, the universal synthesis of HEOs with high purity still faces challenge. In this work, a one-step molten salt method is reported for the synthesis of phase-pure rock salt-type (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O. When used as an anode material for lithium-ion batteries, (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O exhibits high specific capacity and cycling stability, maintaining a capacity retention of 94% after 220 cycles (0.2 A g−1). The superior performance can be attributed to accelerated electron and ion transport as well as enhanced Li adsorption/coupling induced by internal defects. To further demonstrate the wide applicability of the molten salt method, single-phase spinel and pyrochlore HEOs are also successfully synthesized. The presented molten salt method, with its ease of operation, homogeneous reaction environment and low synthesis temperatures, makes it an ideal synthesis technique for the development of novel HEO powders, especially for electrode materials.

Simple One-Step Molten Salt Method for Synthesizing Highly Efficient MXene-Supported Pt Nanoalloy Electrocatalysts.

MXene-supported noble metal alloy catalysts exhibit remarkable electrocatalytic activity in various applications. However, there is no facile one-step method for synthesizing these catalysts, because the synthesis of MXenes requires a strongly oxidizing environment and the preparation of platinum nanoalloys requires a strongly reducing environment and high temperatures. Hence, achieving coupling in one step is extremely challenging. In this paper, a straightforward one-step molten salt method for preparing MXene-supported platinum nanoalloy catalysts is proposed. The molten salt acts as the reaction medium to dissolve the transition metals and platinum ions at high temperatures. Transition metal ions oxidize the A-site element from its MAX precursor at high temperatures, and the resulting transition metals further reduce platinum ions to form alloys. By coupling Al oxidation and platinum ion reduction using a molten salt solvent, this method directly converts Ti3 AlC2 to a Pt-M@Ti3 C2 Tx catalyst (where M denotes the transition metal). It further offers the possibility of extending the Pt-M phase to binary, ternary, or quaternary platinum-containing nanoalloys and converting the Al-containing MAX phase to Ti2 AlC and Ti3 AlCN. Due to the strong interfacial interaction, the as-prepared Pt-Co@Ti3 C2 Tx is superior to commercial Pt/C (20wt.%) in the hydrogen evolution reaction.

Synthesis of Mn3O4 on carbon cloth for flexible supercapacitors

Mn3O4@CC electrodes were synthesized via a fast one-step molten salt method for flexible quasi-solid symmetric supercapacitors. Mn3O4 grows rapidly in a high polarity molten salt system and strongly anchors to carbon cloth. The molten salt method can realize sodion embedded in Mn3O4 and then improve the conductivity and capacitance. The results show that the Na-0.9-based supercapacitor exhibits a high capacitance of 1225.7 mF cm−2 at 5 mA cm−2. The preparation method, design strategy on structure of composition in this work will provide a novel route to realize high-performance flexible supercapacitors.

Molten-Salt Synthesis of Triazine-Based Carbon Nitride and Its Photocatalytic Degradation Mechanism Investigation by In Situ NMR

Carbon nitride-based catalysts are nonmetallic materials with efficient photocatalysis for water splitting, degradation of organic dyes, and CO2 reduction. In this paper, a one-step molten salt method was employed for the synthesis of ionic doped carbon nitride materials named CNs (carbon nitride catalysts), which exhibited excellent adsorption performance and photocatalytic activity. The adulteration of Zn2+ ions created a unique nanosheet stack morphology, leading to more effective active sites and better electron transfer efficiency. Additionally, the degradation mechanism was investigated by the quasi-in situ NMR method. The reaction products and photocatalytic process were fully discussed, providing a new degradative pathway of methylene blue (MB) by such CN-based catalysts.

Porous heterojunction of Ni2P/Ni7S6 with high crystalline phase and superior conductivity for industrial anion exchange membrane water electrolysis

Limited by sluggish mass and charge transfer in anion exchange membrane (AEM) water electrolysis, designing high crystalline phase and superior conductivity electrocatalysts for oxygen evolution is crucial in promoting application of hydrogen. Herein, maple leaf-shaped porous heterojunction (Ni2P/Ni7S6) is fabricated by one-step molten salt method. Benefited from rich porosity and high crystal structure, the target catalyst with abundant active sites and great mechanical strength only requires the overpotentials of 330 mV to reach 1000 mA cm−2, and can sustain at 500 mA cm−2 for 700 h. Besides, characterizations and theoretical calculations reveal that strong interaction between Ni2P and Ni7S6 leads to a depleted electron density in Ni sites and optimizes the adsorption energy of *OOH and H2O, achieving favorable kinetics and superior conductivity. Meanwhile, assembled AEM water electrolyzer delivers 1000 mA cm−2 at a cell voltage of 1.88 V, operating at the average energy efficiency of 72 % for 140 h.

Molten salt synthesis of NiCo-NiCo2O4@C nanotubes as anode materials for Li-ion batteries

The construction of carbon-encapsulated transition metal nanotube structures is a preferred method that can effectively slow down volume expansion, improve cycling stability and enhance the electrical conductivity of the reactive sites of lithium-ion batteries. In this study, nanotubes of carbon-coated NiCo-NiCo2O4 nanoparticles (NC-NCO@C) were prepared by a one-step molten salt method at high temperature using Ni and Co as catalytic centers and sodium acetate as carbon source. We used NC-NCO@C-2 nanotubes as anode materials for lithium-ion batteries(LIBs), which exhibited excellent lithium storage performance and good stability, with a specific capacity of 616.26 mAh g−1 after 1000 cycles at a high current density of 1 A g−1. In addition, NC-NCO@C-2 were used as anodes in lithium-ion full cells and LiFePO4 (LFP) was used as the cathode. The NC-NCO@C-2//LFP full-cell exhibits high capacity and good cycling stability, with a capacity of 100.7 mAh g−1 after 100 cycles and a capacity retention rate of 92%. The construction of NC, NCO, and carbon ternary complexes was found to activate and promote the reversible conversion of certain inorganic components at the solid electrolyte interfaces (SEI), which effectively reduced the volume change during cycling, increased the electrical conductivity, and improved the cycling stability of the electrode. The proposed one-step molten salt synthesis of Carbon-coated metals complexes with excellent compatibility characteristics, is expected to solve the problem of volume change in transition metals, which is encountered in LIBs applications.

Low-temperature fabrication and properties of porous calcium hexaluminate (CA6) ceramics with low thermal conductivity by one-step method

In this study, one-step molten salt method followed by low-temperature sintering is employed for fabricating porous calcium hexaluminate (CA6) ceramics with ideal plate-like structure and low thermal conductivity via the assistance of CaCl2. The porous CA6 ceramic containing 15 wt% CaCl2 sintered at 1400 °C for 3 h exhibits desirable compressive strength (7.14 MPa), low bulk density (1.47 g/cm3), high porosity (61.12%), and low conductivity (0.439 W/(m·K)). The results imply that CaCl2, as a pore-forming agent and an additional source of CaO, provides a large number of liquid phases and resulting in quantities of closed pores. Moreover, the reactions between molten Al2O3 and CaCl2 alter the mass transfer modes of Al2O3 and accelerate its phase transition to α-Al2O3 in addition to contributing to the conversion of CaCl2 to CaO and the subsequent formation of CA6, which results in the entire synthesis of low-temperature CA6 at around 1400 °C. Therefore, there is no need for extra salt washing treatment owing to the consumption and evaporation of CaCl2, which makes this one-step molten salt method much more advantageous in terms of its economical and highly efficient.

Large-scale synthesis of visible light responsive ZnS by one-step molten salt method

It still remains a big challenge for the large-scale synthesis of visible light responsive ZnS. In this work, a simple one-step molten salt method is developed for large-scale synthesis of visible light responsive ZnS, in which the as-obtained sample at T oC is named as ST (T = 200, 300, 400, 500, 600 °C). The degradation reaction of Rhodamine B (RhB) is used to evaluate photocatalytic activity under visible light (λ ＞ 400 nm). Among the samples, S200 shows the highest visible light activity. Under visible light irradiation (λ ＞ 400 nm), 70% of RhB can be degraded by S200 after 90 min. Typically, the visible light activity of S200 is 28.2 times higher than that of S600. The higher activity of S200 is mainly attributed to more sulfur vacancies (VS), wider light absorption range, higher charge separation efficiency and larger BET area. Specifically, the BET area of S200 (44.4 m2 g−1) is 4.1 times higher than that of S600 (8.7 m2 g−1), thus S200 can provide more active sites. Meanwhile, the photocurrent for S200 is 6 times higher than that of S600, demonstrating that S200 has a higher charge separation efficiency mainly caused by more surface VS. Density functional theory (DFT) calculation further demonstrates that VS is favorable thermodynamically for the adsorptions of O2 and H2O, which benefits the generation of •OH and •O2– active species, leading to an improved activity. After three cycles of RhB degradation, S200 shows outstanding stability with 95% visible-light activity remained. The molten salt method is simple and productive, which can be used for large-scale synthesis of photocatalysts in practice.

A molten salt route to binder-free CeO2 on carbon cloth for high performance supercapacitors

Cerium oxide is one of the most abundant and environment-benignity rare earth oxides, which is thus of interesting to explore its feasibility to serve as a safe and efficient candidate for supercapacitor electrodes. We report herein a facile one-step molten salt method to synthesize CeO2 nanoparticles abundant in surface oxygen vacancies, which are directly grown on a carbon cloth (CeO2@CC). The CeO2@CC exhibits a high specific capacitance of 811.5 mF cm−2 at the current density of 5 mA cm−2 in −0.8–0 V, with a good capacitance retention of 86.3 % at 5 mA cm−2 after 10,000 cycles in 6 M KOH aqueous electrolyte. When assembled with a Co3O4@CC positive electrode, the Co3O4@CC//CeO2@CC asymmetric supercapacitor achieves an energy density of 0.11 mWh cm−2 at a power density of 3.25 mW cm−2. Both the abundant oxygen vacancies and the conductive carbon cloth contribute to the electrochemical performance. This work suggests that CeO2 could be a candidate material for high performance supercapacitors.

Experimental and DFT studies of flower-like Ni-doped Mo2C on carbon fiber paper: A highly efficient and robust HER electrocatalyst modulated by Ni(NO3)2 concentration

Developing highly efficient and stable non-precious metal catalysts for water splitting is urgently required. In this work, we report a facile one-step molten salt method for the preparation of self-supporting Ni-doped Mo2C on carbon fiber paper (Ni-Mo2CCB/CFP) for hydrogen evolution reaction (HER). The effects of nickel nitrate concentration on the phase composition, morphology, and electrocatalytic HER performance of Ni-doped Mo2C@CFP electrocatalysts was investigated. With the continuous increase of Ni(NO3)2 concentration, the morphology of Mo2C gradually changes from granular to flower-like, providing larger specific surface area and more active sites. Doping nickel (Ni) into the crystal lattice of Mo2C largely reduces the impedance of the electrocatalysts and enhances their electrocatalytic activity. The as-developed Mo2C-3 M Ni(NO3)2/CFP electrocatalyst exhibits high catalytic activity with a small overpotential of 56 mV at a current density of 10 mA·cm−2. This catalyst has a fast HER kinetics, as demonstrated by a very small Tafel slope of 27.4 mV·dec−1, and persistent long-term stability. A further higher Ni concentration had an adverse effect on the electrocatalytic performance. Density functional theory (DFT) calculations further verified the experimental results. Ni doping could reduce the binding energy of Mo-H, facilitating the desorption of the adsorbed hydrogen (Hads) on the surface, thereby improving the intrinsic catalytic activity of Ni-doped Mo2C-based catalysts. Nevertheless, excessive Ni doping would inhibit the catalytic activity of the electrocatalysts. This work not only provides a simple strategy for the facile preparation of non-precious metal electrocatalysts with high catalytic activity, but also unveils the influence mechanism of the Ni doping concentration on the HER performance of the electrocatalysts from the theoretical perspective.

Morphology and facet tailoring of CaSnO3 assembled in molten salt with defect-mediated photocatalytic activity

Modulation of perovskite oxide toward controlled active facets and defects has attracted much attention. However, the influence of facets and defects on the photocatalytic activity are still ambiguous, especially for the alkaline-earth stannates. In this work, a high-efficiency CaSnO3 semiconductor photocatalyst was prepared by a facile one-step molten salt method without adding a capping agent. By simply varying the solutes, three kinds of CaSnO3 with different morphology were successfully synthesized, including sphere, cube, and cuboctahedron. Meanwhile, both the facet exposure and formation of defects affected the photocatalytic performance of CaSnO3 samples. The formation mechanism for various CaSnO3 morphology and their facet-dependent photocatalytic performances were explored in detail, which indicated that the formation of {100} facets was beneficial for the photocatalytic performance rather than {111}. Although these samples showed similar absorption edges, the varying amount of oxygen vacancy was one of the reasons for the diverse photocatalytic activity. The distortion of crystal structure of CaSnO3 was due to the formation of reduced Sn, which could influence the bond and angle of Sn–O–Sn and subsequently the photocatalytic activity. Different scavengers were also used to identify the role of active species in the photo-degradation process. The relationships between surface electronic structure, oxygen vacancy, and oxidation state of B site with the photocatalytic activity of tin stannate were clearly revealed.

Ni(NO3)2-induced high electrocatalytic hydrogen evolution performance of self-supported fold-like WC coating on carbon fiber paper prepared through molten salt method

Exploring high-performance and inexpensive electrocatalysts for hydrogen evolution reaction to substitute Pt-based compounds is important to sustain hydrogen production. Herein, WC based self-supported catalysts doped with different concentration of nickel nitrate solution (Ni(NO3)2) were synthesized on carbon fiber paper (CFP) by one-step molten salt method (abbreviated as x Ni-WC@CFP). With the increasing of Ni(NO3)2 concentration, fold-like structures were formed on the catalysts, which was conducive to active sites exposure. As Ni(NO3)2 concentration increased from 1M to 5M, the catalytic performance of the electrocatalyst showed a trend of increasing first and then decreasing. The optimal 4M Ni-WC@CFP showed comparable catalytic ability in 0.5M H2SO4 with a low overpotential of 73 mV at 10 mA cm−2 and Tafel slope of 66.4 mV dec−1. However, excessive nickel doping would inhibit HER performance. The density functional theory calculation further verified the experimental results. The adsorption energy of hydrogen showed a decreasing trend with the rising amount of Ni doped in, while the W-H binding energy would change in an opposite direction as over doped Ni. This work provided an insight for the preparation of high-efficiency self-supported W-based electrocatalysts and expounded the influence trend of Ni doping concentration on the performance of electrocatalysts.

Direct upcycling of mixed Ni-lean polycrystals to single-crystal Ni-rich cathode materials

•The upcycling process can regenerate market-preferred NMC cathode materials •The upcycling process overcomes the limitation of feedstock and the final product •The upcycled materials have good rate and cycle performance With the widespread adoption of Li-ion batteries (LIBs), recycling of these devices has attracted much attention. The direct recycling of LIBs is the most efficient method for manufacturing sustainability because it aims to regenerate specific cathode materials back to their original performance without the chemical decomposition of secondary particles. However, the recovered cathode material composition may be considered outdated or obsolete. Meanwhile, traditional direct recycling requires additional sorting and separating steps for mixed cathode streams. Here, our new direct upcycling process uses a one-step molten salt method to convert spent polycrystalline Ni-lean cathodes into single-crystal Ni-rich cathodes, which could be applied to mixed cathode streams without additional sorting and separating steps. The obtained upcycled cathode materials exhibit improved capacity and stability beyond that of commercial materials. Thus, this methodology demonstrates a pathway toward the sustainable development of LIBs. With the widespread adoption of Li-ion batteries (LIBs), recycling of these devices has attracted much attention. The direct recycling of LIBs is the most efficient method for manufacturing sustainability because it aims to regenerate specific cathode materials back to their original performance without the chemical decomposition of secondary particles. However, the recovered cathode material composition may be considered outdated or obsolete. Meanwhile, traditional direct recycling requires additional sorting and separating steps for mixed cathode streams. Here, our new direct upcycling process uses a one-step molten salt method to convert spent polycrystalline Ni-lean cathodes into single-crystal Ni-rich cathodes, which could be applied to mixed cathode streams without additional sorting and separating steps. The obtained upcycled cathode materials exhibit improved capacity and stability beyond that of commercial materials. Thus, this methodology demonstrates a pathway toward the sustainable development of LIBs.

Enhanced visible light photocatalytic performance of crystalline g-C3N4 nanosheets by one-step molten salt method

The crystalline g-C3N4 nanosheets have been successfully prepared by one-step molten salts method. The microstructures and optical properties of as-prepared samples were characterized by different techniques, such as XRD, EDS, XPS, SEM, TEM, BET, PL and Uv–vis DRS. The results showed that the unit of the crystalline g-C3N4 nanosheets was composed of triazine ring, which was different from heptazine-based g-C3N4. The crystalline g-C3N4 nanosheets were thin and transparent, which were similar to graphene. The crystalline g-C3N4 nanosheets exhibits the excellent photocatalytic activity, which can degrade 98% RhB within 120 min under visible light irradiation. However, the degradation efficiency of bulk g-C3N4 is only 40% within 120 min. The enhanced photocatalytic activity of g-C3N4 nanosheets can be attributed to 2D nanosheet morphology, which inhibits the electron-hole recombination. In addition, the high specific surface area of g-C3N4 nanosheets positively increases the contact area with pollutants, making the degradation reaction more efficiently. A plausible photocatalytic mechanism was proposed for the degradation of RhB under visible light irradiation.

A simple one-step molten salt method for synthesis of micron-sized single primary particle LiNi0.8Co0.1Mn0.1O2 cathode material for lithium-ion batteries

A simple one-step molten salt method was used to synthesize micron-sized single primary particle LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material. XRD, SEM, cycle performance, rate capability, differential capacity curves, 0.1 C charge/discharge curves, and EIS were carried out to research the mechanism regarding the influence of Li/transition metal (Li/TM) ratio, sinter temperature, and sinter time on the morphology and electrochemical properties of micron-sized single primary particle LiNi0.8Co0.1Mn0.1O2 materials. Any one of these three factors increases exceeding certain limit and it will lead to the degradation of active structure evolution during the charge/discharge process, resulting in decreasing electrochemical performance of the cathode material. The micron-sized single primary particle NCM811 cathode material with little aggregation and primary particle size of ~ 1–2 μm was produced successfully under the condition of heating at 850 °C for 16 h with Li/TM = 1.15. This work will be helpful for the synthesis of micron-sized single primary particle NCM cathode materials for lithium-ion batteries.

Band structure engineering of PTI in C-PTI/ZnO heterostructures for enhanced visible-light-driven H2 evolution

Polytriazine imide (PTI), a triazine-based carbon nitride has a wider band gap and more positive conduction band (CB) potential compared to those of graphitic carbon nitride (g-C3N4). Therefore, it is highly desired to develop an effective strategy to optimize the band structure of PTI for the enhancement of the photocatalytic performance, especially upshift the conductive band potential. Here, a ternary C-PTI/ZnO (CPZ) photocatalyst was developed via a simple one-step molten salt method. In the obtained CPZ sample, the carbon ring in-plane connects to the triazine ring, leading to the formation of C-PTI nanosheets. The carbon ring incorporation not only efficiently narrows the band gap of PTI, but also shifts its conduction band potential negatively and accelerates the photogenerated electron transport. In addition, ZnO nanoparticles are well dispersed on the C-PTI nanosheets, further promoting the charge carriers transfer and separation. As a result, the CPZ sample presents a photocatalytic H2 evolution rate up to 52 μmol h−1 under visible light, which is 60 and 179 times higher than that of C-PTI and PTI, respectively.