Catalytic Effect Research Articles

Unlocking the Catalytic Potential of Anionic Micelles: Insights into the Ce(IV)-Directed Phenylalanine Oxidation Kinetics in Asymmetric Hydrophobic Environments.

The oxidation kinetics of phenylalanine (Phe) by Ce(IV) have been examined in both the absence and presence of aqueous micellar media with asymmetric tails, specifically using sodium dodecyl sulfate (SDS) and sodium tetradecyl sulfate (STS) surfactants. The reaction progress was monitored by observing a decrease in absorbance using UV-vis spectroscopy. Interestingly, the kinetic profile revealed a consistent increase in the observed rate constant values as the concentration of the surfactant increased. The kinetic results have been analyzed by using numerous experimental studies, such as dynamic light scattering (DLS), zeta potential, 1H NMR analysis, FT-IR spectroscopy, conductometry, scanning electron microscopy (SEM), fluorometry, time-correlated single-photon counting (TCSPC), and transmission electron microscopy (TEM). Micellar aggregates maintain their spherical shape in the presence of the substrate, even at higher surfactant concentrations, as revealed by microstructural analysis. The substrate molecules are encapsulated to a greater extent in the inner micellar core of STS micelles on account of the more hydrophobic nature of STS surfactants. Therefore, in STS micellar media, fewer substrate molecules diffuse to the Stern layer compared to the SDS micellar medium, resulting in fewer molecules participating in the oxidative transformation reaction. As a result, the rate enhancement of oxidation kinetics is less pronounced in STS micelles than in SDS micelles. A plausible mechanism that aligns with the kinetic results has been highlighted, along with the interpretation of the Piszkiewicz model, to explain the observed catalytic effect of both micellar mediums.

Assessment of clinical competencies of medical students in a simulated environment: a scoping review protocol

Simulation in scenarios representative of clinical practice is an innovative teaching-learning strategy. Performance evaluation in this scenario must be carried out using methods that are valid, reliable, equivalent, feasible, acceptable, have an educational impact and a catalytic effect. It is therefore necessary to understand the methods available for this purpose. The aim was therefore to outline a scoping protocol on the assessment methods used to analyze the clinical competencies of medical students in a simulated environment. This protocol was conducted according to the methods proposed by the Joanna Briggs Institute (JBI) and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). The review question was defined based on the PCC (Population, Concept, Context) mnemonic: “What methods are used to assess the clinical skills of medical students in a simulated environment?”. The eligibility criteria are associated with publications in English, Portuguese and Spanish, available in full text, covering methodological approaches including qualitative, quantitative, mixed methods, primary research, systematic reviews, meta-analyses, letters, guidelines, published theses and dissertations, with no time frame. The searches will be carried out in the Scopus, CINAHL, Web of Science, Lilacs, PubMed and Scielo databases. The results will be presented in tables or diagrams, accompanied by explanatory text, according to the best use for the purpose of the review.

Design, Synthesis, and Performance of Novel Nano‐CoO/NiO‐loaded and Sulfonation‐Modified ZSM‐5 Composite Catalyst for In Situ Conversion of Oil Shale

ABSTRACTA novel composite catalyst with readily preparation and good catalytic performance was designed and synthesized using sulfonation‐modified zeolite socony mobil‐5 (ZSM‐5) as the carrier and nano‐CoO/NiO as the active components. Compared with traditional in situ conversion, the composite catalyst could effectively reduce the activation energy of catalytic reactions, improve the efficiency of oil and gas conversion, and ameliorate the quality of oil products. When the loading amount of nano‐CoO/NiO was 20 wt% and the silicon/aluminum ratio of ZSM‐5 was 40–50, the required activation energy for oil shale cracking was as low as 43.64 kJ/mol, the yield of oil products was as high as 15.46 wt%, and the content of organic compounds in medium‐/low‐carbon hydrocarbon was as high as 71.50%. The prepared composite catalysts had low preparation cost, environmental friendliness, and significant catalytic effects, providing a feasible approach for the effective exploitation and utilization of oil shale.

Study on the Economic Effects of Opening Up Guangxi Higher Education to the ASEAN

With the promotion of the “Belt and Road” Initiative, education cooperation between China and ASEAN countries has increased, highlighting the opening of education to the outside world. In this context, exploring the opening-up pattern of higher education to ASEAN countries and the regional differences it shows, as well as the positive catalytic effect of international student mobility on regional economic development, is particularly urgent and important. By using CiteSpace, we find that the economic effect of opening up higher education to the outside world has become the focus of academic attention. Closely following this hotspot, this paper analyses the current situation of Guangxi's higher education in opening up to ASEAN countries and finds that although Guangxi has achieved initial results in attracting international students from ASEAN countries, there is still much room for improvement in terms of improving the quality of education and teaching and enhancing economic attractiveness. Moreover, opening up to ASEAN countries not only directly promotes the growth of Guangxi's outward foreign direct investment but also greatly promotes mutual benefits and creates a win‒win situation between the two sides in many fields, such as education and cultural exchanges and economic and trade exchanges. Given this, the government should promote trade and investment facilitation, encourage RMB settlement, promote the integration of industry and education clusters, and create an innovation highland for higher education openness and cooperation toward ASEAN countries.

Hydrogen Release from Ammonia: Size and Support Effects in Heterogeneous Transition Metal Catalysis

Ammonia can serve as a promising renewable energy carrier based on its high hydrogen content and energy density as well as its full‐fledged transportation infrastructure. Renewable hydrogen can be converted in ammonia synthesis, stored and/or transported bound in ammonia and released on demand by ammonia decomposition. The most active catalysts for this reaction are Ru‐based due to its optimal nitrogen binding energy compared to other transition metals. However, the development of alternative non‐noble transition metal catalysts such as Fe, Ni or Co is attractive. For supported metal catalysts, size and support effects play important roles in many catalytic reactions resulting in a change of geometric and/or electronic properties. In this review, we first discuss existing studies of size and support effects on Ru, Fe, Ni, Co catalysts in ammonia decomposition from an experimental and theoretical viewpoint. Afterwards, we compare the available catalytic data in the form of TOFH2 and reaction rate for each metal catalyst supported on different supports and as a function of particle size, attempting to identify an optimum particle size and a trend for the different supports. Finally, we discuss the challenges and perspectives of future research on the size and support effect in ammonia decomposition.

Preparation of Single‐Crystal MoS2 Nanotubes and 1D Van der Waals Heterostructures

AbstractSingle‐crystal MoS2 nanotubes possess outstanding electronic and optoelectronic properties. However, previous attempts to synthesize MoS2 nanotubes are hindered by poor crystallinity and the high strain energy required to roll a sheet with three atomic layers into a tubular structure. Here, the confined template growth of well‐crystallized MoS2 nanotubes encapsulated within carbon nanotubes, forming 1D van der Waals heterostructures, is reported. The growth of MoS2 nanotubes is catalyzed by iron carbide. CNTs serve as nanoreactors and structurally confined templates, ensuring the growth of fine MoS2 nanotubes. Water vapor is employed to manipulate the structure and morphology of resultant MoS2. Free‐standing MoS2 nanotubes are obtained by removing outer CNTs with gentle plasma etching. This method demonstrate the power of coupling the catalytic effect and the space confinement in the growth of high‐quality MoS2 nanotubes, which may become a common strategy for the preparation of general 1D nanostructures of various transition metal dichalcogenides and other materials.

The Importance of Catalytic Effects in Hot-Electron-Driven Chemical Reactions.

Hot electrons (HEs) represent out-of-equilibrium carriers that are capable of facilitating reactions which are inaccessible under conventional conditions. Despite the similarity of the HE process to catalysis, optimization strategies such as orbital alignment and adsorption kinetics have not received significant attention in enhancing the HE-driven reaction yield. Here, we investigate catalytic effects in HE-driven reactions using a compositional catalyst modification (CCM) approach. Through a top-down alloying process and systematic characterization, using electrochemical, photodegradation, and ultrafast spectroscopy, we are able to disentangle chemical effects from competing electronic phenomena. Correlation between reactant energetics and the HE reaction yield demonstrates the crucial role of orbital alignment in HE catalytic efficiency. Optimization of this parameter was found to enhance HE reaction efficiency 5-fold, paving the way for tailored design of HE-based catalysts for sustainable chemistry applications. Finally, our study unveils an emergent ordering effect in photocatalytic HE processes that imparts the catalyst with an unexpected polarization dependence.

Enhancing the Thermal Stability and Combustion Performance of NC-Based Propellants via Bu-NENA Modification.

In this paper, a series of insensitive smokeless nitrocellulose (NC)-based propellants were prepared through the absorption rolling method. Their thermal stability was rigorously assessed via vacuum stability test (VST), and their thermal reactivity of the propellant was comprehensively investigated and compared using the thermogravimetric analysis (TG)/differential scanning calorimetry (DSC) technique. Additionally, the combustion characteristics were meticulously analyzed by a constant-volume combustion diagnosis system. The experimental results showed that the thermal stability of the propellant was significantly enhanced when N-butyl-N-nitratoethyl nitramine (Bu-NENA) was used to partially or fully replace nitroglycerin (NG). However, an increase in Bu-NENA content corresponded with a decrease in the burning rate of the propellant. The catalytic effects observed in propellants varied markedly, influencing the composition of the products formed during thermal decomposition. Specifically, substituting 50 and 100% of NG with Bu-NENA resulted in reductions in the decomposition heat release of 96.2 and 258 J·g-1, respectively. Furthermore, the introduction of the catalyst significantly increased the burning rate under low-pressure conditions. For instance, at 2 MPa, the burning rate of Bu-0503 increased from 1.78 to 5.23 mm·s-1. A lower content of Bu-NENA was associated with a more luminous flame, while substituting 50 and 100% of NG with Bu-NENA led to decreases in flame temperature by 222 and 535 °C, respectively. The observed decrease in the flame temperature is attributed to the heat absorption during the volatilization of Bu-NENA, leading to a reduction in the thermal feedback of the flame.

Improving CO2 desorption performance in monoethanolamine solutions by adding titanium pyrophosphate catalyst

Catalytic CO2 desorption has emerged as a crucial strategy for enhancing the efficiency of CO2 capture and reducing energy requirements, thereby advancing chemical absorption methods. This study examines the catalytic effectiveness of titanium pyrophosphate (TiP2O7) in improving monoethanolamine (MEA)-based CO2 absorption and desorption processes, comparing its performance with other titanium-based catalysts, including titanium dioxide (TiO2), titanium tetrahydroxide (TiO(OH)2), and titanium carbide (TiC). In TiP2O7, Ti ions function as Lewis acid sites by accepting electron pairs (LASs), P2O74− anions act as proton carriers, facilitating rapid proton transfer as Lewis base sites (LBSs), and active hydroxyl groups on the surface, resulting from water molecule dissociation or the deprotonation reaction, function as Brönsted acid sites (BASs). These sites work synergistically to accelerate CO2 desorption. TiP2O7 outperforms the other catalysts tested, primarily due to its optimal Brönsted/Lewis (B/L) ratio. This characteristic is particularly advantageous for regenerating RNHCOO−, as the reaction predominantly follows a hydrogen transfer pathway facilitated by the BASs. Consequently, TiP2O7 enhances the CO2 desorption rate by 41.5% at a desorption temperature of 91 °C, while simultaneously reducing the relative heat duty by 13% compared to processes without catalysts.

In Situ Synthesis of Iron-Based Porphyrin Metal-Organic Frameworks for the Baeyer-Villiger Oxidation Using Air as an Oxidant.

Iron-based porphyrin metal-organic frameworks (PMOFs) are a new type of material with good stability, catalytic activities, and reusability, which have broad application prospects. However, the synthesis of iron-based PMOFs with different metalloporphyrin units requires a considerable amount of reagents and time. Herein, an in situ synthesis method was developed to simplify the synthetic process of iron-based PMOFs. A series of highly stable iron-based PMOFs (Msitu-PMOF-3(Fe) (M = Fe, Co, Ni, Cu, Pd)) were synthesized in one pot without the preparation of metalloporphyrin ligands in advance. This synthesis method is simpler and more efficient, saving considerable time and material costs. The resultant Msitu-PMOF-3(Fe) exhibits a high tolerance to aqueous solutions with pH ranging from 0 to 11, as well as various organic solvents. The catalytic experiments show that both Fesitu-PMOF-3(Fe) and Cositu-PMOF-3(Fe) can catalyze the Baeyer-Villiger oxidation of cyclohexanone using air as an oxidant at 35 °C. Moreover, when the mixtures of Fesitu-PMOF-3(Fe) and Cositu-PMOF-3(Fe) were employed as catalyst, they can exert a cooperative catalysis effect, resulting in a significantly enhanced catalytic activity compared to a single component. The mild reaction condition, high catalytic efficiency, and excellent selectivity endow this catalytic system with a good application prospect. This work not only provides a new approach for the synthesis of iron-based PMOFs but also offers guidance for the Baeyer-Villiger oxidation reactions using air under mild conditions.

Enhanced photocatalytic degradation of crystal violet and malachite green oxalate dyes by NiAg2O infused chitosan nanocomposites

The present study investigated the catalysis of Lupeol-loaded chitosan nanoparticles infused with NiAg2O nanoparticles to create a NiAg2O/Lup@CS nanocomposite. Recent advances in nanomaterials with unique architectures and functionalities have successfully treated contaminated soil and industrial wastewaters. Consequently, a lupeol@chitosan nanoparticle loaded with NiAg2O was created, and its catalytic effectiveness in degrading industrial dye pollution was examined. The ionic gelation synthesis route was used to produce the NiAg2O/Lup@CS nanocomposite. After that, the resultant nanocomposite underwent extensive analysis to determine its elemental composition through EDAX, surface bonding, nature, crystallinity using FTIR, FESEM, and XRD, and powdered particle size using HRTEM. Subsequently, the produced nanocomposite's efficacy in photo-catalytically degrading Crystal violet and Malachite green oxalate were evaluated. Moreover, the Crystal violet and Malachite green oxalate degradation kinetics were studied using the Langmuir–Hinshelwood model, which also offered a plausible photocatalytic process. The catalytic mechanism suggested that the addition of Lup@CS nanoparticles would have had the effect of speeding up photocurrent transport by increasing the quantity of electrons and holes produced by the photon's irradiation. This highlights the significance of creating innovative composite photocatalysts. The study also observed the superior photocatalytic activity of NiAg2O/Lup@CS nanocomposite with 86.14 % degradation of Crystal violet and 86.65 % degradation of Malachite green oxalate.

Exploration of microwave absorptivity and catalysis of CMF@Co-MoS2 for microwave-initiated depolymerization of lignin

Obtaining key platform chemicals from lignin is a sustainable refining concept of the non-petroleum route. Rapid pyrolysis is a potential refining technology, and microwave-assisted catalytic depolymerization with low energy consumption is preferred. Herein, we reported the strategy of microwave-initiated depolymerization using a self-designed dynamic vapor flow reaction system with a facilely prepared CMF@Co-MoS2-0.18 catalyst, achieving efficient conversion of lignin (Dealkalize) to monophenol. Under constant microwave irradiation (2.45 GHz), the CMF@Co-MoS2-0.18 catalyst had excellent dielectric properties (Dielectric loss factor: 0.56) and microwave heating properties (∼140 s rise to ∼ 600℃). Therefore, microwave-initiated depolymerization of lignin showed that the CMF@Co-MoS2-0.18 catalyst can improve the monophenol content (54.72 %) and phenol selectivity (35.84 %) under the synergistic effect of microwave absorptivity and catalysis. The reaction of the lignin model and kinetics analysis show that the CMF@Co-MoS2-0.18 catalyst increases the yield of monophenol by reducing depolymerization activation energy and selectively breaking the β-O-4 bond. The finite element analysis pointed out that under microwave irradiation, CMF@Co-MoS2-0.18 continuously conducted heat to lignin and the lignin vapor would have sufficient energy to collide with the catalyst active site at a high frequency, which led to an increase in the pre-exponential factor and initiated catalytic depolymerization lignin. In summary, we provide a potential pathway for the rapid conversion of lignin into key platform chemicals.

Hollow and heterojunction-structured Janus nanomotors for pyroelectrodynamic and nanozyme-catalyzed tumor therapy

Pyroelectrodynamic therapy (PEDT) has emerged as an attractive therapeutic modality for tumors, but is dramatically discounted by inherent defects of wide band gap, fast electron − hole recombination and low photothermal utilization. Herein, hollow-structured Janus nanoparticles (NPs) are developed to improve tumor accumulation and PEDT generation of reactive oxidative species (ROS) for antitumor treatment. Hollow barium titanate (hBT) NPs were prepared by the template and hydrothermal method for in situ deposition of CuS nanodots and then partially coated with polydopamine (PDA) caps to obtain hBT-CuS@PDA. Finite element analysis reveals that the unique thin shell of hBT benefits transportation of pyroelectrically generated charge carriers through shortening diffusion distance to the interface. The CuS deposition forms heterojunctions with hBT to accelerate electron − hole separation and leads to a larger pyroelectric current. The hollow structure facilitates light absorption and conversion, and the photothermal effect of the half-coated PDA caps generates asymmetric temperature gradient to drive NP locomotion across biological barriers. The in situ generated pyroelectric field selectively affects membrane potential and fluidity of tumor cells to enhance the specific NP internalization. The pyroelectric effect enhances the peroxidase-like activity of CuS nanodots to generate toxic ·OH and the glutathione peroxidase-like activity to inhibit glutathione consumption of ROS. The integration of photothermal, pyroelectric, nanozyme catalysis and self-protrusion effects promotes NP accumulation and penetration throughout tumors to exhibit therapeutic effect at a mild-temperature, reducing the possible high-temperature ablation of normal tissues. The hollow and heterjunction structure generates abundant intracellular ROS and efficient diffusion in tumor tissues to inhibit tumor growth and extend animal survival, offering a safe and effective PEDT strategy.

TiO2 intercalated MWCNTs nanocomposite sensor for the detection and quantification of 5-Fluorouracil

The present analysis deals with the fabrication of novel electrochemical sensing platforms for the determination of the anti-cancer drug 5-Fluorouracil (5-FLU). Multiwalled carbon nanotubes/titanium dioxide nanoparticles (TiO2·MWCNTs) modified carbon paste electrodes were constructed and used to quantify 5-FLU in pH 7.0. TiO2·MWCNTs nanocomposite reveals a non-uniform distribution of agglomerated TiO2 nanoparticles over the smooth surface of MWCNTs At the TiO2∙MWCNTs/CPE, the 5-FLU molecule underwent an irreversible electro-oxidation process. The proposed electrode platform exhibited a high catalytic effect for the 5-FLU. The TiO2∙MWCNTs/CPE sensor shows the detection limits of 2.7nM for 5-FLU with sensitivity of 82.15µA·µM−1·cm−2. The sensor was employed to detect the desired drug moiety in the urine samples of pharmaceutical drugs along with spiked water and soil samples; the good recovery values demonstrating the applicability and selectivity of the sensor were supported by excipient interference investigation. Thus, the developed sensors and method makes them a promising alternative for future research to determine other bio-active molecules in pharmaceutical and clinical samples.

Catalytic effect of potassium sulfate on propane dehydrogenation of alumina-supported Pt catalyst

Catalytic effect of potassium sulfate on propane dehydrogenation of alumina-supported Pt catalyst

Significant Enhancement Catalytic Activity of Nitrile Hydratase by Balancing the Subunits Expression.

Escherichia coli (E. coli) is the most commonly used bacterial recombinant protein production system due to its easy genetic modification properties. In our previous study, a recombinant plasmid expressing the Fe-type nitrile hydratase derived from Rhodococcus erythropolis CCM2595 (ReNHase) was successfully constructed and the recombinant ReNHase exerted an excellent catalytic effect on dinitrile compounds. Nevertheless, the ReNHases were confronted with imbalanced subunit expression during heterologous expression, which restricted the enzymes assemble functionally. In this study, the secondary structure of mRNA in the ribosome binding sequence region of the β-subunit was optimized to elevate the translation efficiency of the β-subunit gene and balance the expression of α- and β-subunits in ReNHase. The optimized ReNHase showed a 12-fold increase in specific enzyme activity over wild-type ReNHase. To further enhance the soluble expression of ReNHase, the ReNHase was labeled using three different fusion tags, resulting in three new recombinant ReNHases. In these recombinant ReNHases, some of the fusion tags promoted the soluble expression of ReNHase, but also affected the balance of α-/β-subunit expression and the secondary structure of the ReNHase, and reduced the enzyme activity. In conclusion, our results provide an optimized strategy for the heterologous expression of multi-subunit proteins.

Tunable protic ionic liquid catalysts for the efficient one-step synthesis of isosorbide-based polycarbonates

Using CO2-derived dimethyl carbonate (DMC) instead of diphenyl carbonate (DPC) as a carbonyl source for synthesizing bio-based polycarbonates is a green and cost-effective route. However, the synthesis of high-performance polycarbonates via the DMC route remains challenging due to the poor reactivity and selectivity of DMC compared to DPC. Herein, we designed a series of highly active protic ionic liquid (PIL) catalysts for the synthesis of poly(isosorbide carbonate) (PIC) from DMC with ISB. The influences of the structures of anion and cation on the catalytic activity of PILs were systematically studied. Compared with the reported aprotic IL catalysts, the unique reactive hydrogen of the cation in PILs could form a strong hydrogen bond interaction with the carbonyl group of DMC, resulting in higher reactivity of the carbonyl carbon of DMC. Moreover, the nucleophilicity of the anion could be easily tuned by adjusting the pKa value, which effectively realized the balance of the reactivity difference between exo-OH and endo-OH in ISB. Among them, [DBUH][Im] showed the highest catalytic activity, and the weight-average molecular weight (Mw) and glass transition temperature of PIC reached 55,700 g/mol and 160 °C, respectively. Combined with NMR analyses and DFT calculations, the mechanism that exhibited the synergetic catalytic effect of anion-cation for the polymerization of DMC and ISB was presented.

Assessing the discrepant role of anions in the transformation of reactive oxygen species in H2O2 and PDS system: A comparative kinetic analysis

Clarifying reactive oxygen species (ROS) variation in the presence of co-existing anions is significant for understanding the catalytic effect of magnetite (Fe3O4)-induced advanced oxidation processes (AOPs) in natural environment, yet this remains controversial. Herein, we compare the specific impacts of NO3-, SO42-, and Cl- on ROS (•OH, SO4•-, O2•-, and 1O2) exposure concentration in H2O2 and peroxydisulfate (PDS) systems, as well as how these variations affect the catalytic efficiency by developing kinetic model. In both two systems, NO3- demonstrates no discernible effect on ROS, whereas SO42- inhibits the exposure of all ROS and thus micropollutants degradation. Through theoretical calculation, it is proposed that SO42- primarily exerts its influence through affecting the electronic structure over catalyst surface. Regarding Cl-, it affects ROS exposure mainly by reacting with ROS. It shows inhibitory effect on 1O2 in both systems, but its suppressive impact on •OH is markedly more pronounced in H2O2 system compared to PDS system, which may be related to its rapid reactivity with SO4•-. Besides, the chlorine radicals (mainly ClO•) generated through the reaction of Cl- may exert a selective influence on micropollutants degradation. This study can help to re-understand the influence behavior of co-existing anions during AOPs.

Catalytic effect of the in-situ rhodium(III) complexes in surfactant medium on the auto-oxidation of 1,2-hydroxyphenylthiourea: A theoretical and experimental study for rhodium(III) sensing

1,2-hydroxyphenylthiourea(HPTU) undergoes auto-oxidation to form an yellow colored dimer. The process of auto-oxidation is enhanced by the presence of trace quantities of transition metal ions and transition metal complexes that act as catalysts. In the current study, catalytic potential of rhodium(III) complexes on the auto-oxidation of 1,2-hydroxyphenylthiourea(HPTU) was studied theoretically using quantum mechanical calculations and experiments were carried out using photometry and fluorometry. DFT studies inferred that [Rh(Py)6]Cl3 showed a better catalytic activity in the dimerization of HPTU. Theoretical studies were subsequently validated through experiments using photometric methods and the range of detection was determined to be 6 ng/mL–100 ng/mL. The detection limit was observed to be 2 ng/mL. Analytical parameters such as pH, reagent concentration, metal ion concentration, appropriate activators and surfactants were established.

Catalytic pyrolysis mechanism of tetrabromobisphenol A by calcium oxide: A density functional theory study

In this paper, the mechanisms of catalytic pyrolysis of tetrabromobisphenol A (TBBPA) by calcium oxide (CaO) were studied through density functional theory methods. The results indicate that the phenolic hydroxyl group of TBBPA is the preferred site for CaO to extract protons, and the generated anion further transforms into 2,6-dibromophenol via demethylation and hydrogen transfer reactions. The reaction activity of CaO with hydrogen bromide is relatively high, with an energy barrier of 133.2 kJ/mol. CaO produces calcium ions, which combine with bromine ions to form calcium bromide to achieve the purpose of fixing bromine. In addition, the participation of calcium ions results in the OH bond being easier to crack, which further lowers the reaction energy barrier of keto-enol tautomerism reactions H2O produced during catalytic pyrolysis also has an obvious catalytic effect, and the energy barrier of the keto-enol tautomerism reaction decreased from 309.1 kJ/mol to 150.6 kJ/mol with the participation of H2O.