Pub Date : 2024-07-31DOI: 10.1134/s0023158423601134
Dong Peng, Qing Wang, Shaohong Zang, Liuye Mo
Abstract
Volatile organic compounds (VOCs), play a crucial role as precursors of ozone (O3) and secondary organic aerosols, making them significant air pollutants. Efforts to effectively eliminate ethyl acetate (EA), a typical VOC in many industrial processes, has attracted significant attention worldwide. In this study, a catalyst consisting of MgAl2O4 spinel prepared via the sol-gel method was adopted to support MnOx by incipient wetness impregnation for complete catalytic oxidation of EA. The prepared catalysts were characterized by XRD, SEM, TEM, BET, XPS and H2-TPR. It was found that the calcination temperature of the support is crucial for the catalytic activity. The optimal calcination temperature of the support is found to be 800°C, resulting in a perfect MgAl2O4 spinel phase and a crystalline size of 8.3 nm. The optimized MnOx/MA-800 displayed high catalytic activity (T95 = 240°C) and stability due to its high reduction ability and high atomic ratios of Mn4+/Mn3+ and Oads/O.
{"title":"Catalytic Complete Oxidation of Ethyl Acetate on MnOx/MgAl2O4 Catalysts","authors":"Dong Peng, Qing Wang, Shaohong Zang, Liuye Mo","doi":"10.1134/s0023158423601134","DOIUrl":"https://doi.org/10.1134/s0023158423601134","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Volatile organic compounds (VOCs), play a crucial role as precursors of ozone (O<sub>3</sub>) and secondary organic aerosols, making them significant air pollutants. Efforts to effectively eliminate ethyl acetate (EA), a typical VOC in many industrial processes, has attracted significant attention worldwide. In this study, a catalyst consisting of MgAl<sub>2</sub>O<sub>4</sub> spinel prepared via the sol-gel method was adopted to support MnO<sub><i>x</i></sub> by incipient wetness impregnation for complete catalytic oxidation of EA. The prepared catalysts were characterized by XRD, SEM, TEM, BET, XPS and H<sub>2</sub>-TPR. It was found that the calcination temperature of the support is crucial for the catalytic activity. The optimal calcination temperature of the support is found to be 800°C, resulting in a perfect MgAl<sub>2</sub>O<sub>4</sub> spinel phase and a crystalline size of 8.3 nm. The optimized MnO<sub><i>x</i></sub>/MA-800 displayed high catalytic activity (<i>T</i><sub>95</sub> = 240°C) and stability due to its high reduction ability and high atomic ratios of Mn<sup>4+</sup>/Mn<sup>3+</sup> and O<sub>ads</sub>/O.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1134/s0023158424600044
Hui-Qin Zheng, Jun Wang, Ming-Cai Yin, Yao-Ting Fan
Abstract
Two novel Ru(II)-phenanthroline derivatives complexes, Ru-1 and Ru-2, were synthesized and characterized. The key distinction between Ru-1 and Ru-2 lies in their ligands: L1 (2-hydroxy-5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl) benzoic acid) and L2 (2-hydroxy-3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzoic acid). In L1, the –OH group is located in the para-position, while in L2, it resides in the ortho-position. Subsequently, Pt/TiO2 and Ru-1/Pt/TiO2 (and Ru-2/Pt/TiO2) composites were prepared using photo-deposition and impregnation methods, respectively. The Ru-1/Pt/TiO2 and Ru-2/Pt/TiO2 composites were thoroughly characterized using various techniques, including ultraviolet-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectroscopy (FL), cyclic voltammetry (CV) experiments, and other relevant techniques. Photocatalytic hydrogen production systems were established by employing Ru-1/Pt-TiO2 and Ru-2/Pt-TiO2 as photocatalysts and ascorbic acid (H2A) as a sacrificial reagent. The results demonstrated that the maximum hydrogen production reached 1461 μmol (Ru-1/Pt/TiO2) and 843 μmol (Ru-2/Pt/TiO2) under optimized conditions with 20 mg of composite photocatalyst, 0.3 mol L–1 of H2A, and pH 4, within 4 h of irradiation (λ > 420 nm). Correspondingly, the photocatalytic hydrogen production rates were 18 267 and 10 523 μmol g–1 h–1, respectively. Mechanism studies revealed that electrons flow from the highest occupied molecular orbital (HOMO) of Ru-1 to the conduction band (CB) of TiO2, subsequently combining with H+ on the surface of the Pt metal nanoparticles to generate hydrogen gas. The holes on the lowest unoccupied molecular orbital (LUMO) of the photosensitizer are oxidized by H2A, thereby regenerating the activity of the composite catalyst by restoring the photosensitizer.
{"title":"Enhancement of Photocatalytic Activity for Hydrogen Production of Nano-TiO2 Using Ru(II)-Phenantroline Derivatives","authors":"Hui-Qin Zheng, Jun Wang, Ming-Cai Yin, Yao-Ting Fan","doi":"10.1134/s0023158424600044","DOIUrl":"https://doi.org/10.1134/s0023158424600044","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Two novel Ru(II)-phenanthroline derivatives complexes, Ru-1 and Ru-2, were synthesized and characterized. The key distinction between Ru-1 and Ru-2 lies in their ligands: L1 (2-hydroxy-5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl) benzoic acid) and L2 (2-hydroxy-3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzoic acid). In L1, the –OH group is located in the <i>para</i>-position, while in L2, it resides in the <i>ortho-</i>position. Subsequently, Pt/TiO<sub>2</sub> and Ru-1/Pt/TiO<sub>2</sub> (and Ru-2/Pt/TiO<sub>2</sub>) composites were prepared using photo-deposition and impregnation methods, respectively. The Ru-1/Pt/TiO<sub>2</sub> and Ru-2/Pt/TiO<sub>2</sub> composites were thoroughly characterized using various techniques, including ultraviolet-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectroscopy (FL), cyclic voltammetry (CV) experiments, and other relevant techniques. Photocatalytic hydrogen production systems were established by employing Ru-1/Pt-TiO<sub>2</sub> and Ru-2/Pt-TiO<sub>2</sub> as photocatalysts and ascorbic acid (H<sub>2</sub>A) as a sacrificial reagent. The results demonstrated that the maximum hydrogen production reached 1461 μmol (Ru-1/Pt/TiO<sub>2</sub>) and 843 μmol (Ru-2/Pt/TiO<sub>2</sub>) under optimized conditions with 20 mg of composite photocatalyst, 0.3 mol L<sup>–1</sup> of H<sub>2</sub>A, and pH 4, within 4 h of irradiation (λ > 420 nm). Correspondingly, the photocatalytic hydrogen production rates were 18 267 and 10 523 μmol g<sup>–1</sup> h<sup>–1</sup>, respectively. Mechanism studies revealed that electrons flow from the highest occupied molecular orbital (HOMO) of Ru-1 to the conduction band (CB) of TiO<sub>2</sub>, subsequently combining with H<sup>+</sup> on the surface of the Pt metal nanoparticles to generate hydrogen gas. The holes on the lowest unoccupied molecular orbital (LUMO) of the photosensitizer are oxidized by H<sub>2</sub>A, thereby regenerating the activity of the composite catalyst by restoring the photosensitizer.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1134/s0023158423601262
C. Rajashree, A. R. Balu, S. Chitra Devi, C. Kayathiri, K. Devendran, M. Sriramraj, A. Vinith
Abstract
Photocatalytic and antibacterial properties of PbS:Ag (PA) and rGO-blended PbS:Ag (rPA) nanoparticles (NPs) have been compared and reported in this paper. Chemical precipitation and one-pot synthesis methods were used to synthesize NPs of PA and rPA. X-ray diffraction (XRD) studies reveal a cubic crystal structure for both samples, with preferential growth along the (200) plane. Crystallite sizes were 55 and 41 nm for PA and rPA, respectively. Scanning electron microscopy (SEM) images of rPA revealed clustered grains. Both samples exhibited Pb–S bands in Fourier-transform infrared spectroscopy (FTIR) studies. Near band edge emissions occurred at 504, 520, 539 and 595 nm for both PA and rPA. The inclusion of rGO into PA led to lattice misfit, crystal growth disorders, and increased grain boundary scattering. This series of structural disruptions contributed to a reduction in the photoluminescence (PL) intensity for the rPA composite. A higher degradation efficiency of 95.4% was achieved for the rPA catalyst against Rhodamine B dye under visible light. The antibacterial activity of PA is increased with rGO inclusion due to increased generation of reactive oxygen species (ROS).
{"title":"rGO Blended PbS:Ag Nanoparticles for Rhodamine B Dye Degradation and Growth Inhibition of S. aureus and E. coli Bacterial Strains","authors":"C. Rajashree, A. R. Balu, S. Chitra Devi, C. Kayathiri, K. Devendran, M. Sriramraj, A. Vinith","doi":"10.1134/s0023158423601262","DOIUrl":"https://doi.org/10.1134/s0023158423601262","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Photocatalytic and antibacterial properties of PbS:Ag (PA) and rGO-blended PbS:Ag (rPA) nanoparticles (NPs) have been compared and reported in this paper. Chemical precipitation and one-pot synthesis methods were used to synthesize NPs of PA and rPA. X-ray diffraction (XRD) studies reveal a cubic crystal structure for both samples, with preferential growth along the (200) plane. Crystallite sizes were 55 and 41 nm for PA and rPA, respectively. Scanning electron microscopy (SEM) images of rPA revealed clustered grains. Both samples exhibited Pb–S bands in Fourier-transform infrared spectroscopy (FTIR) studies. Near band edge emissions occurred at 504, 520, 539 and 595 nm for both PA and rPA. The inclusion of rGO into PA led to lattice misfit, crystal growth disorders, and increased grain boundary scattering. This series of structural disruptions contributed to a reduction in the photoluminescence (PL) intensity for the rPA composite. A higher degradation efficiency of 95.4% was achieved for the rPA catalyst against Rhodamine B dye under visible light. The antibacterial activity of PA is increased with rGO inclusion due to increased generation of reactive oxygen species (ROS).</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423601158
M. B. Pshenitsyn, O. A. Boeva, A. S. Konopatsky, A. Yu. Antonov, K. N. Zhavoronkova
Abstract
The purpose of this work was to study the catalytic properties of mono- and bimetallic nanoparticles of the copper–silver system of variable composition supported on aluminum oxide in the conversion reactions of protium modifications and deuterium–hydrogen exchange. From a comparison of the temperature dependences of the specific catalytic activity of samples in the two test reactions, a conclusion on different reaction mechanisms was drawn. It was shown that, compared to the bulk metals, CunAgm nanoparticles had catalytic properties over a wide temperature range down to –196°C. In the chemical reaction of isotope exchange in molecular hydrogen, a synergistic effect was observed, which indicated the interaction of metals in bimetallic nanoparticles.
{"title":"Catalysis on Mono- and Bimetallic CunAgm Nanoparticles of the Silver–Copper System","authors":"M. B. Pshenitsyn, O. A. Boeva, A. S. Konopatsky, A. Yu. Antonov, K. N. Zhavoronkova","doi":"10.1134/s0023158423601158","DOIUrl":"https://doi.org/10.1134/s0023158423601158","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The purpose of this work was to study the catalytic properties of mono- and bimetallic nanoparticles of the copper–silver system of variable composition supported on aluminum oxide in the conversion reactions of protium modifications and deuterium–hydrogen exchange. From a comparison of the temperature dependences of the specific catalytic activity of samples in the two test reactions, a conclusion on different reaction mechanisms was drawn. It was shown that, compared to the bulk metals, Cu<sub><i>n</i></sub>Ag<sub><i>m</i></sub> nanoparticles had catalytic properties over a wide temperature range down to –196°C. In the chemical reaction of isotope exchange in molecular hydrogen, a synergistic effect was observed, which indicated the interaction of metals in bimetallic nanoparticles.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423601249
L. B. Belykh, N. I. Skripov, E. A. Milenkaya, T. A. Kornaukhova, T. P. Sterenchuk, Yu. K. Stepanova, F. K. Schmidt
Abstract
The properties of Pd/HZSM-5 and Pd–nP/HZSM-5 catalysts were studied in direct synthesis and side processes of decomposition and hydrogenation of H2O2 under mild conditions in ethanol and aqueous ethanol in the presence of an acid inhibitor. It was shown, using HRTEM, XRD, and ICP MS methods, that modification with phosphorus led to the formation of highly dispersed X-ray amorphous systems, which are structurally disordered solid solutions of phosphorus in palladium. The main factors governing the promoting effect of phosphorus on the yield of H2O2 are considered. It was established that the use of a zeolite support in the H form, along with the phosphorus and acid modifiers, inhibits the side process of H2O2 decomposition.
摘要 研究了 Pd/HZSM-5 和 Pd-nP/HZSM-5 催化剂在乙醇和有酸抑制剂存在的乙醇水溶液中，在温和条件下直接合成 H2O2 并将其分解和加氢的副反应过程中的性质。使用 HRTEM、XRD 和 ICP MS 方法表明，磷修饰导致形成高度分散的 X 射线无定形体系，这是磷在钯中的结构无序固溶体。研究考虑了磷对 H2O2 产率的促进作用的主要因素。研究证实，使用 H 形式的沸石支持物以及磷和酸改性剂可抑制 H2O2 分解的副过程。
{"title":"Properties of Palladium-Phosphorus Catalysts Supported on HZSM-5 Zeolite in Direct Synthesis of Hydrogen Peroxide","authors":"L. B. Belykh, N. I. Skripov, E. A. Milenkaya, T. A. Kornaukhova, T. P. Sterenchuk, Yu. K. Stepanova, F. K. Schmidt","doi":"10.1134/s0023158423601249","DOIUrl":"https://doi.org/10.1134/s0023158423601249","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The properties of Pd/HZSM-5 and Pd–<i>n</i>P/HZSM-5 catalysts were studied in direct synthesis and side processes of decomposition and hydrogenation of H<sub>2</sub>O<sub>2</sub> under mild conditions in ethanol and aqueous ethanol in the presence of an acid inhibitor. It was shown, using HRTEM, XRD, and ICP MS methods, that modification with phosphorus led to the formation of highly dispersed X-ray amorphous systems, which are structurally disordered solid solutions of phosphorus in palladium. The main factors governing the promoting effect of phosphorus on the yield of H<sub>2</sub>O<sub>2</sub> are considered. It was established that the use of a zeolite support in the H form, along with the phosphorus and acid modifiers, inhibits the side process of H<sub>2</sub>O<sub>2</sub> decomposition.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423601171
N. I. Baranov, E. I. Bagrii, R. E. Safir, A. G. Cherednichenko, K. V. Bozhenko, A. L. Maksimov
Abstract
The thermodynamic parameters of formation reactions (total energy at 0 K, enthalpy, and Gibbs free energy at a temperature of 298.15 K and a pressure of 101 325 Pa) were estimated in the B3LYP-D3(BJ)/6-311++G** approximation for the products of ionic alkylation of adamantane and lower alkyladamantanes with ethylene and propylene. Aluminum chloride was used as an acid catalyst model. The quantum-chemical calculations demonstrated the effect of methyl groups in adamantanes and the molecular weight of the olefin on the energetics of formation of the corresponding alkyl- and alkenyladamantanes.
摘要 采用 B3LYP-D3(BJ)/6-311++G**近似估算了金刚烷和低级烷基金刚烷与乙烯和丙烯离子烷基化产物的形成反应热力学参数（0 K 时的总能、焓和温度为 298.15 K、压力为 101 325 Pa 时的吉布斯自由能）。氯化铝被用作酸催化剂模型。量子化学计算表明，金刚烷中的甲基和烯烃的分子量对形成相应的烷基和烯基金刚烷的能量有影响。
{"title":"Quantum-Chemical Study of Formation of Alkyl- and Alkenyladamantanes by Ionic Alkylation with Olefins","authors":"N. I. Baranov, E. I. Bagrii, R. E. Safir, A. G. Cherednichenko, K. V. Bozhenko, A. L. Maksimov","doi":"10.1134/s0023158423601171","DOIUrl":"https://doi.org/10.1134/s0023158423601171","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The thermodynamic parameters of formation reactions (total energy at 0 K, enthalpy, and Gibbs free energy at a temperature of 298.15 K and a pressure of 101 325 Pa) were estimated in the B3LYP-D3(BJ)/6-311++G** approximation for the products of ionic alkylation of adamantane and lower alkyladamantanes with ethylene and propylene. Aluminum chloride was used as an acid catalyst model. The quantum-chemical calculations demonstrated the effect of methyl groups in adamantanes and the molecular weight of the olefin on the energetics of formation of the corresponding alkyl- and alkenyladamantanes.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423601195
L. N. Skvortsova, I. A. Artyukh, T. V. Tatarinova, K. A. Bolgaru
Abstract
The photocatalytic generation of hydrogen from aqueous solutions of formic acid under irradiation with visible light with the use of tantalum-containing metal–ceramic composites based on silicon nitride was investigated depending on the substrate concentration and the pH of suspension in the absence and with the addition of hydrogen peroxide. These compounds were obtained by self-propagating high temperature synthesis (SHS) using the combustion of ferrosilicon aluminum (FSA) and a mixture of silicon and aluminum powders with tantalum additives in an atmosphere of nitrogen. It was found that the dependence of the rate of photocatalytic hydrogen production on the concentration of formic acid without hydrogen peroxide was described by the Langmuir–Hinshelwood mechanism. In the presence of hydrogen peroxide, the rate of the photocatalytic process sharply increased with the concentration of formic acid. The highest rate of hydrogen evolution from formic acid was observed on an iron-containing composite synthesized from FSA without the addition of hydrogen peroxide, and it amounted to 4.55 µmol/min.
{"title":"Kinetic Mechanisms of the Photocatalytic Generation of Hydrogen from Formic Acid Using Metal–Ceramic Composites under Visible-Light Irradiation","authors":"L. N. Skvortsova, I. A. Artyukh, T. V. Tatarinova, K. A. Bolgaru","doi":"10.1134/s0023158423601195","DOIUrl":"https://doi.org/10.1134/s0023158423601195","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The photocatalytic generation of hydrogen from aqueous solutions of formic acid under irradiation with visible light with the use of tantalum-containing metal–ceramic composites based on silicon nitride was investigated depending on the substrate concentration and the pH of suspension in the absence and with the addition of hydrogen peroxide. These compounds were obtained by self-propagating high temperature synthesis (SHS) using the combustion of ferrosilicon aluminum (FSA) and a mixture of silicon and aluminum powders with tantalum additives in an atmosphere of nitrogen. It was found that the dependence of the rate of photocatalytic hydrogen production on the concentration of formic acid without hydrogen peroxide was described by the Langmuir–Hinshelwood mechanism. In the presence of hydrogen peroxide, the rate of the photocatalytic process sharply increased with the concentration of formic acid. The highest rate of hydrogen evolution from formic acid was observed on an iron-containing composite synthesized from FSA without the addition of hydrogen peroxide, and it amounted to 4.55 µmol/min.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423600657
Pooja, Anjali Goel, Rajni Lasyal
Abstract
In this study, the kinetics of catalytic degradation of methyl red, an anionic azo dye, by hexacyanoferrate(III) ions in the presence of ultrafine Ir–Cu bimetallic nanoparticles has been investigated. The effect of various parameters, including the concentration of dye, oxidant, Ir–Cu bimetallic nanoparticles (BMNPs), and solution pH on the reaction rate was investigated by measuring the light absorption at a wavelength of 425 nm, corresponding to the maximum absorption of the dye. The results reveal that the reaction follows first-order kinetics with respect to the concentration of hexacyanoferrate(III), methyl red, and Ir–Cu BMNPs at an optimum pH of 8.0 and a constant temperature of 40 ± 0.1°C. In order to determine how electrolytes interact with the reaction rate, the impact of ionic strength on the degradation rate was also examined. The high catalytic activity of Ir–Cu BMNPs was demonstrated by a three to four-fold rise in the reaction rate with increasing concentration of Ir–Cu BMNPs (particle size ca. 0.98nm). Thermodynamic parameters including activation energy (Ea), enthalpy of activation (ΔH#), entropy of activation (ΔS#), and free energy of formation (ΔF#) of the reaction were calculated by analyzing the reaction rate at four different temperatures within the 40 to 55°C range. The low value of activation energy also suggests a high degradation rate. A reaction mechanism through complex formation was proposed based on the experimental findings which were supported by the analysis of the products formed. The formation of simpler and less hazardous products (1,5-pentanediol and benzoic acid) was verified by UV–Vis spectroscopy and liquid chromatography and mass spectroscopy (LC–MS). The assessment of turnover frequencies for each catalytic cycle also proved the stability and reusability of the catalyst. As a result, the discovery offers an innovative and highly cost-effective solution for environmental safety against dye contamination, with the potential for expansion to additional toxins.
{"title":"Degradation of Methyl Red Azo Dye by Hexacyanoferrate(III) Ions from Water using Ultrafine Ir–Cu Bimetallic Nanoparticles: a Kinetic Approach","authors":"Pooja, Anjali Goel, Rajni Lasyal","doi":"10.1134/s0023158423600657","DOIUrl":"https://doi.org/10.1134/s0023158423600657","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this study, the kinetics of catalytic degradation of methyl red, an anionic azo dye, by hexacyanoferrate(III) ions in the presence of ultrafine Ir–Cu bimetallic nanoparticles has been investigated. The effect of various parameters, including the concentration of dye, oxidant, Ir–Cu bimetallic nanoparticles (BMNPs), and solution pH on the reaction rate was investigated by measuring the light absorption at a wavelength of 425 nm, corresponding to the maximum absorption of the dye. The results reveal that the reaction follows first-order kinetics with respect to the concentration of hexacyanoferrate(III), methyl red, and Ir–Cu BMNPs at an optimum pH of 8.0 and a constant temperature of 40 ± 0.1°C. In order to determine how electrolytes interact with the reaction rate, the impact of ionic strength on the degradation rate was also examined. The high catalytic activity of Ir–Cu BMNPs was demonstrated by a three to four-fold rise in the reaction rate with increasing concentration of Ir–Cu BMNPs (particle size <i>ca.</i> 0.98nm). Thermodynamic parameters including activation energy (<i>E</i><sub>a</sub>), enthalpy of activation (Δ<i>H</i><sup>#</sup>), entropy of activation (Δ<i>S</i><sup>#</sup>), and free energy of formation (Δ<i>F</i><sup>#</sup>) of the reaction were calculated by analyzing the reaction rate at four different temperatures within the 40 to 55°C range. The low value of activation energy also suggests a high degradation rate. A reaction mechanism through complex formation was proposed based on the experimental findings which were supported by the analysis of the products formed. The formation of simpler and less hazardous products (1,5-pentanediol and benzoic acid) was verified by UV–Vis spectroscopy and liquid chromatography and mass spectroscopy (LC–MS). The assessment of turnover frequencies for each catalytic cycle also proved the stability and reusability of the catalyst. As a result, the discovery offers an innovative and highly cost-effective solution for environmental safety against dye contamination, with the potential for expansion to additional toxins.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423600967
Z. Bailiche, A. Berrichi, R. Bachir
Abstract
Gold nanoparticles supported over mesoporous ceria (Au/CeO2), titania (Au/TiO2) and iron oxide (Au/Fe2O3) were prepared by deposition-precipitation with urea and used for toluene oxidation. The mesoporous CeO2, Fe2O3, andTiO2 were synthesized employing a hard-template approach using SBA-15 as the template. The catalysts were characterized by BET, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), diffuse reflectance UV-Vis spectroscopy (DR/UV-Vis), and high-resolution transmission electron microscopy (HRTEM). Based on the temperature required to achieve 50% toluene conversion in the oxidation reaction (T50%), the activity sequence was Au/CeO2 > Au/Fe2O3 > Au/TiO2. The Au/CeO2 catalyst was the most active catalyst, achieving 50% toluene conversion at 240°C and full toluene conversion at 295°C demonstrating high stability over successive catalytic runs.
{"title":"Effect Ofmesoporous Supports on Gold Nanoparticles Activity in Toluene Oxidation","authors":"Z. Bailiche, A. Berrichi, R. Bachir","doi":"10.1134/s0023158423600967","DOIUrl":"https://doi.org/10.1134/s0023158423600967","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Gold nanoparticles supported over mesoporous ceria (Au/CeO<sub>2</sub>), titania (Au/TiO<sub>2</sub>) and iron oxide (Au/Fe<sub>2</sub>O<sub>3</sub>) were prepared by deposition-precipitation with urea and used for toluene oxidation. The mesoporous CeO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, andTiO<sub>2</sub> were synthesized employing a hard-template approach using SBA-15 as the template. The catalysts were characterized by BET, X-ray diffraction (XRD), H<sub>2</sub>-temperature programmed reduction (H<sub>2</sub>-TPR), diffuse reflectance UV-Vis spectroscopy (DR/UV-Vis), and high-resolution transmission electron microscopy (HRTEM). Based on the temperature required to achieve 50% toluene conversion in the oxidation reaction (<i>T</i><sub>50%</sub>), the activity sequence was Au/CeO<sub>2</sub> > Au/Fe<sub>2</sub>O<sub>3</sub> > Au/TiO<sub>2</sub>. The Au/CeO<sub>2</sub> catalyst was the most active catalyst, achieving 50% toluene conversion at 240°C and full toluene conversion at 295°C demonstrating high stability over successive catalytic runs.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-09DOI: 10.1134/s0023158423601225
A. V. Zhurenok, A. A. Sushnikova, A. A. Valeeva, A. Yu. Kurenkova, D. D. Mishchenko, E. A. Kozlova, A. A. Rempel’
Abstract
The photocatalytic activity of the g-C3N4/TiO2 composite samples in the processes of dye (methylene blue) decomposition and hydrogen evolution from an aqueous ethanol solution under the action of visible radiation (400 nm) has been studied. A new original method for the synthesis of the g-C3N4/TiO2 composite by depositing g-C3N4/TiO2 to TiO2 nanoparticles during sol-gel synthesis is proposed. The synthesized photocatalysts were characterized by X-ray diffraction, low-temperature gas adsorption, X-ray photoelectron spectroscopy, high-resolution transmission microscopy, and diffuse reflectance spectroscopy in the UV and visible regions. The maximum activity in the hydrogen evolution reaction was 1.3 mmol ({text{g}}_{{{text{cat}}}}^{{ - 1}}) h–1, which exceeds the rate of hydrogen evolution on the unmodified g-C3N4 and TiO2 samples.
{"title":"Composite Photocatalysts g-C3N4/TiO2 for Hydrogen Production and Dye Decomposition","authors":"A. V. Zhurenok, A. A. Sushnikova, A. A. Valeeva, A. Yu. Kurenkova, D. D. Mishchenko, E. A. Kozlova, A. A. Rempel’","doi":"10.1134/s0023158423601225","DOIUrl":"https://doi.org/10.1134/s0023158423601225","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The photocatalytic activity of the g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composite samples in the processes of dye (methylene blue) decomposition and hydrogen evolution from an aqueous ethanol solution under the action of visible radiation (400 nm) has been studied. A new original method for the synthesis of the g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composite by depositing g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> to TiO<sub>2</sub> nanoparticles during sol-gel synthesis is proposed. The synthesized photocatalysts were characterized by X-ray diffraction, low-temperature gas adsorption, X-ray photoelectron spectroscopy, high-resolution transmission microscopy, and diffuse reflectance spectroscopy in the UV and visible regions. The maximum activity in the hydrogen evolution reaction was 1.3 mmol <span>({text{g}}_{{{text{cat}}}}^{{ - 1}})</span> h<sup>–1</sup>, which exceeds the rate of hydrogen evolution on the unmodified g-C<sub>3</sub>N<sub>4</sub> and TiO<sub>2</sub> samples.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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