V. Tarabanko, K. L. Kaygorodov, A. Kazachenko, Marina A. Smirnova, Yulia V. Chelbina, Yury Kosivtsov, Viktor A Golubkov
The influence of mass transfer intensity on the kinetics of the catalytic oxidation of flax shives with oxygen in alkaline media to aromatic aldehydes and pulp was studied. The process was carried out in two autoclaves, with moderate stirring (stirrer engine of 8 W) and intense stirring (stirrer engine of 200 W). The oxidation of flax shives into vanillin, syringaldehyde, and pulp was shown to proceed as a completely diffusion-controlled process under the studied conditions, both moderate and intense stirring. Depending on the process conditions, it can be limited by stages of oxygen transfer through the diffusion boundary layer near the gas–liquid interface (low intensity of mass transfer) as well as by reagents’ inner diffusion in the porous and solid matter of the flax shive particle (high intensity of mass transfer). The results on the influence of the stirring speed and volume of the reaction mass on the rates of oxygen consumption and vanillin accumulation were obtained. They were described using a known simple model connecting the intensity of mass transfer and the stirring power density in the bulk of the liquid phase in terms of algebra equations.
{"title":"Mass Transfer in the Processes of Native Lignin Oxidation into Vanillin via Oxygen","authors":"V. Tarabanko, K. L. Kaygorodov, A. Kazachenko, Marina A. Smirnova, Yulia V. Chelbina, Yury Kosivtsov, Viktor A Golubkov","doi":"10.3390/catal13121490","DOIUrl":"https://doi.org/10.3390/catal13121490","url":null,"abstract":"The influence of mass transfer intensity on the kinetics of the catalytic oxidation of flax shives with oxygen in alkaline media to aromatic aldehydes and pulp was studied. The process was carried out in two autoclaves, with moderate stirring (stirrer engine of 8 W) and intense stirring (stirrer engine of 200 W). The oxidation of flax shives into vanillin, syringaldehyde, and pulp was shown to proceed as a completely diffusion-controlled process under the studied conditions, both moderate and intense stirring. Depending on the process conditions, it can be limited by stages of oxygen transfer through the diffusion boundary layer near the gas–liquid interface (low intensity of mass transfer) as well as by reagents’ inner diffusion in the porous and solid matter of the flax shive particle (high intensity of mass transfer). The results on the influence of the stirring speed and volume of the reaction mass on the rates of oxygen consumption and vanillin accumulation were obtained. They were described using a known simple model connecting the intensity of mass transfer and the stirring power density in the bulk of the liquid phase in terms of algebra equations.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"111 35","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nianhua Liu, Rong Tang, Kai Li, Bin Wang, Junze Zhao, Qing Xu, M. Ji, J. Xia
Photocatalytic nitrogen fixation has attracted much attention because of its ability to synthesize ammonia under mild conditions. However, the ammonia yield is still greatly limited by the sluggish charge separation and extremely high N2 dissociation energy. Herein, two-dimensional Ti3C2 MXene ultrathin nanosheets were introduced to construct Ti3C2/TiO2 composites via electrostatic adsorption for photocatalytic nitrogen fixation. The photocatalytic activity experiments showed that after adding 0.1 wt% Ti3C2, the ammonia yield of the Ti3C2/TiO2 composite reached 67.9 μmol L−1 after 120 min of light irradiation, nearly 3 times higher than that of the monomer TiO2. XPS, DRS, LSV, and FTIR were used to explore the possible photocatalytic nitrogen fixation mechanism. Studies showed that a close interfacial contact has been formed via the bonding mode of =C-O between the Ti3C2 and TiO2 samples. The formed =C-O bond boosts an oriented photogenerated charge separation and transfer in the Ti3C2/TiO2 composite. This work provides a promising idea for constructing other efficient MXene-based composite photocatalysts for artificial photosynthesis.
{"title":"Steering Charge Directional Separation in MXenes/Titanium Dioxide for Efficient Photocatalytic Nitrogen Fixation","authors":"Nianhua Liu, Rong Tang, Kai Li, Bin Wang, Junze Zhao, Qing Xu, M. Ji, J. Xia","doi":"10.3390/catal13121487","DOIUrl":"https://doi.org/10.3390/catal13121487","url":null,"abstract":"Photocatalytic nitrogen fixation has attracted much attention because of its ability to synthesize ammonia under mild conditions. However, the ammonia yield is still greatly limited by the sluggish charge separation and extremely high N2 dissociation energy. Herein, two-dimensional Ti3C2 MXene ultrathin nanosheets were introduced to construct Ti3C2/TiO2 composites via electrostatic adsorption for photocatalytic nitrogen fixation. The photocatalytic activity experiments showed that after adding 0.1 wt% Ti3C2, the ammonia yield of the Ti3C2/TiO2 composite reached 67.9 μmol L−1 after 120 min of light irradiation, nearly 3 times higher than that of the monomer TiO2. XPS, DRS, LSV, and FTIR were used to explore the possible photocatalytic nitrogen fixation mechanism. Studies showed that a close interfacial contact has been formed via the bonding mode of =C-O between the Ti3C2 and TiO2 samples. The formed =C-O bond boosts an oriented photogenerated charge separation and transfer in the Ti3C2/TiO2 composite. This work provides a promising idea for constructing other efficient MXene-based composite photocatalysts for artificial photosynthesis.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"42 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139209112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Catalysis stands as a fundamental driver in the energy landscape, influencing processes across the entire energy life cycle [...]
催化是能源领域的基本驱动力，影响着整个能源生命周期中的各种过程 [...]
{"title":"Catalysts in Energy Applications","authors":"Oleg V. Levin","doi":"10.3390/catal13121484","DOIUrl":"https://doi.org/10.3390/catal13121484","url":null,"abstract":"Catalysis stands as a fundamental driver in the energy landscape, influencing processes across the entire energy life cycle [...]","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"38 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139198798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sagarkumar Rajendrakumar Shah, N. J. Mazumdar, Ander Centeno-Pedrazo, D. Deka, N. Artioli, H. Manyar
Carbon dioxide is ideal for carboxylation reactions as a renewable and sustainable C1 feedstock and has significant recognition owing to its low cost, non-toxicity, and high abundance. To depreciate the environmental concentration of CO2, which causes the greenhouse gas effect, developing new catalytic protocols for organic synthesis in CO2 utilization is of great importance. This review focuses on carboxylation reactions using CO2 as a C1 feedstock to synthesize value-added functionalized carboxylic acids and their corresponding derivatives via catalytically generated allyl metal intermediates, photoredox catalysis, and electrocatalysis with a focus on recent developments and opportunities in catalyst design for carboxylation reactions. In this article, we describe recent developments in the carboxylation of C–H bonds, alkenes, and alkynes using CO2 as the C1 source for various reactions under different conditions, as well as the potential direction for the further development of CO2 utilization in organic synthesis.
二氧化碳作为一种可再生和可持续的 C1 原料，是羧化反应的理想原料，并因其低成本、无毒性和高丰度而得到广泛认可。为了降低导致温室气体效应的二氧化碳在环境中的浓度，开发新的利用二氧化碳进行有机合成的催化方案具有重要意义。本综述侧重于以二氧化碳为 C1 原料的羧化反应，通过催化生成的烯丙基金属中间体、光氧化催化和电催化合成高附加值的功能化羧酸及其相应衍生物，重点介绍羧化反应催化剂设计方面的最新进展和机遇。在本文中，我们将介绍在不同条件下以 CO2 为 C1 源进行各种反应的 C-H 键、烯烃和炔烃羧化反应的最新进展，以及在有机合成中进一步开发 CO2 利用的潜在方向。
{"title":"Recent Advances in Catalyst Design for Carboxylation Using CO2 as the C1 Feedstock","authors":"Sagarkumar Rajendrakumar Shah, N. J. Mazumdar, Ander Centeno-Pedrazo, D. Deka, N. Artioli, H. Manyar","doi":"10.3390/catal13121489","DOIUrl":"https://doi.org/10.3390/catal13121489","url":null,"abstract":"Carbon dioxide is ideal for carboxylation reactions as a renewable and sustainable C1 feedstock and has significant recognition owing to its low cost, non-toxicity, and high abundance. To depreciate the environmental concentration of CO2, which causes the greenhouse gas effect, developing new catalytic protocols for organic synthesis in CO2 utilization is of great importance. This review focuses on carboxylation reactions using CO2 as a C1 feedstock to synthesize value-added functionalized carboxylic acids and their corresponding derivatives via catalytically generated allyl metal intermediates, photoredox catalysis, and electrocatalysis with a focus on recent developments and opportunities in catalyst design for carboxylation reactions. In this article, we describe recent developments in the carboxylation of C–H bonds, alkenes, and alkynes using CO2 as the C1 source for various reactions under different conditions, as well as the potential direction for the further development of CO2 utilization in organic synthesis.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"16 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139202671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Asgar Pour, Marwan M. Abduljawad, Yasser A. Alassmy, Mohammed S. Alnafisah, Mustapha El Hariri El Nokab, Paul H. M. Van Steenberge, Khaled O. Sebakhy
Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.
{"title":"Synergistic Catalytic Effects of Alloys of Noble Metal Nanoparticles Supported on Two Different Supports: Crystalline Zeolite Sn-Beta and Carbon Nanotubes for Glycerol Conversion to Methyl Lactate","authors":"Z. Asgar Pour, Marwan M. Abduljawad, Yasser A. Alassmy, Mohammed S. Alnafisah, Mustapha El Hariri El Nokab, Paul H. M. Van Steenberge, Khaled O. Sebakhy","doi":"10.3390/catal13121486","DOIUrl":"https://doi.org/10.3390/catal13121486","url":null,"abstract":"Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"11 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139207811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qi Sun, Haipeng Yang, Jie Wan, Wanru Hua, Yanjun Liu, Xiaoli Wang, Chunxiao Shi, Qingai Shi, Gongde Wu, R. Zhou
5Cu-USY and Ce-doped 5Cu8Ce-USY zeolite catalysts were prepared by the conventional impregnation method. The obtained catalysts were subjected to the hydrothermal ageing process. The catalytic performance of the selective catalytic reduction of NOx with NH3 (NH3-SCR) was evaluated on both fresh and aged catalysts. Physical/chemical characterizations such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were performed, along with detailed in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) experiments including CO adsorption, NH3 adsorption, and NO + O2 reactions. Results showed that, for the 5Cu-USY catalyst, hydrothermal ageing treatment could somehow improve the low-temperature SCR activity, but it also led to significant formation of unfavorable byproducts NO2 and N2O. Such an activity change can be attributed to hydrothermal ageing inducing the migration of isolated Cu+ species in the sodalite cavities towards the super cages of the USY zeolites. The increased content of Cu+ species in the super cages was beneficial for the low-temperature activity improvement, but, at the same time, it also facilitated ammonia oxidation at high temperatures. Ce doping after hydrothermal ageing has a “double-edged sword” effect on the catalytic performance. First of all, Ce doping can inhibit Cu species migration by self-occupying the internal cage sites; thus, the catalytic performance of 5Cu8Ce-USY-700H remains stable after ageing. Secondly, Ce doping introduces a CuOx–CeO2 strong interaction, which facilitates lattice oxygen mobility by forming more oxygen vacancies so as to increase the concentration of surface active oxygen. These changes, on the one hand, could help to promote further oxidative decomposition of nitrate/nitrite intermediates and improve the catalytic performance. But, on the other hand, it also causes the byproduct generation to become more severe.
采用传统的浸渍法制备了 5Cu-USY 和掺杂 Ce 的 5Cu8Ce-USY 沸石催化剂。将得到的催化剂进行水热老化处理。在新催化剂和老化催化剂上评估了氮氧化物与 NH3 的选择性催化还原（NH3-SCR）的催化性能。对催化剂进行了物理/化学表征，如 X 射线衍射 (XRD)、H2 温度编程还原 (H2-TPR) 和 X 射线光电子能谱 (XPS)，以及详细的原位漫反射红外傅立叶变换光谱 (DRIFTS) 实验，包括 CO 吸附、NH3 吸附和 NO + O2 反应。结果表明，对于 5Cu-USY 催化剂，水热老化处理能在一定程度上提高其低温 SCR 活性，但同时也会导致生成大量不利的副产物 NO2 和 N2O。这种活性变化可归因于水热老化诱导钠长石空穴中孤立的 Cu+ 物种向 USY 沸石的超笼迁移。超笼中 Cu+ 物种含量的增加有利于低温活性的提高，但同时也促进了氨在高温下的氧化。水热老化后掺入 Ce 对催化性能有 "双刃剑 "的作用。首先，掺杂 Ce 可以通过自占内部笼型位点来抑制 Cu 物种的迁移；因此，5Cu8Ce-USY-700H 的催化性能在老化后保持稳定。其次，Ce 的掺杂引入了 CuOx-CeO2 的强相互作用，通过形成更多的氧空位来提高晶格氧的流动性，从而增加表面活性氧的浓度。这些变化一方面有助于促进硝酸盐/亚硝酸盐中间产物的进一步氧化分解，提高催化性能。但另一方面，这也会导致副产品的生成变得更加严重。
{"title":"New Insights into the Effect of Ce Doping on the Catalytic Performance and Hydrothermal Stability of Cu-USY Zeolite Catalysts for the Selective Catalytic Reduction of NO with NH3","authors":"Qi Sun, Haipeng Yang, Jie Wan, Wanru Hua, Yanjun Liu, Xiaoli Wang, Chunxiao Shi, Qingai Shi, Gongde Wu, R. Zhou","doi":"10.3390/catal13121485","DOIUrl":"https://doi.org/10.3390/catal13121485","url":null,"abstract":"5Cu-USY and Ce-doped 5Cu8Ce-USY zeolite catalysts were prepared by the conventional impregnation method. The obtained catalysts were subjected to the hydrothermal ageing process. The catalytic performance of the selective catalytic reduction of NOx with NH3 (NH3-SCR) was evaluated on both fresh and aged catalysts. Physical/chemical characterizations such as X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) were performed, along with detailed in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) experiments including CO adsorption, NH3 adsorption, and NO + O2 reactions. Results showed that, for the 5Cu-USY catalyst, hydrothermal ageing treatment could somehow improve the low-temperature SCR activity, but it also led to significant formation of unfavorable byproducts NO2 and N2O. Such an activity change can be attributed to hydrothermal ageing inducing the migration of isolated Cu+ species in the sodalite cavities towards the super cages of the USY zeolites. The increased content of Cu+ species in the super cages was beneficial for the low-temperature activity improvement, but, at the same time, it also facilitated ammonia oxidation at high temperatures. Ce doping after hydrothermal ageing has a “double-edged sword” effect on the catalytic performance. First of all, Ce doping can inhibit Cu species migration by self-occupying the internal cage sites; thus, the catalytic performance of 5Cu8Ce-USY-700H remains stable after ageing. Secondly, Ce doping introduces a CuOx–CeO2 strong interaction, which facilitates lattice oxygen mobility by forming more oxygen vacancies so as to increase the concentration of surface active oxygen. These changes, on the one hand, could help to promote further oxidative decomposition of nitrate/nitrite intermediates and improve the catalytic performance. But, on the other hand, it also causes the byproduct generation to become more severe.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139198668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The evolution of biocatalysis has undergone an unprecedented boost in response to the human demand for sustainable chemistry, which should enable researchers to make the most complex, selective and specific compounds with minimal ecological impact [...]
{"title":"Multienzymatic Catalysis and Enzyme Co-Immobilization","authors":"Roberto Fernandez-Lafuente","doi":"10.3390/catal13121488","DOIUrl":"https://doi.org/10.3390/catal13121488","url":null,"abstract":"The evolution of biocatalysis has undergone an unprecedented boost in response to the human demand for sustainable chemistry, which should enable researchers to make the most complex, selective and specific compounds with minimal ecological impact [...]","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"346 ","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139204221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The acidity of supports can have a positive effect on their catalytic behaviors. Herein, the effects of HCl treatment of TiO2 on its acidic properties and catalytic activity were investigated. TiO2 was treated with various molar concentrations of HCl. Subsequently, Pd was deposited on the treated TiO2 via the deposition–precipitation method; here, the catalysts were denoted as Pd/xH-T, where X is the molar concentration of HCl. Evidently, the amount of strong acid in TiO2 increased with HCl treatment, whereas that in TiO2 treated with a high concentration (5 M) of HCl decreased. After Pd was supported, the amount of acid slightly decreased compared with that on the TiO2 support; however, the order of the acid amounts was similar. The strong acid density increased such that Pd/2H-T had the highest acid content, whereas Pd/5H-T had the lowest. The Pd/2H-T catalyst exhibited the highest selectivity for THFA (95.4%), thus confirming that the selectivity for THFA is correlated with the amount of strong acid. Thus, THFA selectivity is affected by the number of strongly acid sites.
{"title":"Effect of HCl Treatment on Acidity of Pd/TiO2 for Furfural Hydrogenation","authors":"Hye Jin Song, Ye Eun Kim, J. Jae, Man Sig Lee","doi":"10.3390/catal13121481","DOIUrl":"https://doi.org/10.3390/catal13121481","url":null,"abstract":"The acidity of supports can have a positive effect on their catalytic behaviors. Herein, the effects of HCl treatment of TiO2 on its acidic properties and catalytic activity were investigated. TiO2 was treated with various molar concentrations of HCl. Subsequently, Pd was deposited on the treated TiO2 via the deposition–precipitation method; here, the catalysts were denoted as Pd/xH-T, where X is the molar concentration of HCl. Evidently, the amount of strong acid in TiO2 increased with HCl treatment, whereas that in TiO2 treated with a high concentration (5 M) of HCl decreased. After Pd was supported, the amount of acid slightly decreased compared with that on the TiO2 support; however, the order of the acid amounts was similar. The strong acid density increased such that Pd/2H-T had the highest acid content, whereas Pd/5H-T had the lowest. The Pd/2H-T catalyst exhibited the highest selectivity for THFA (95.4%), thus confirming that the selectivity for THFA is correlated with the amount of strong acid. Thus, THFA selectivity is affected by the number of strongly acid sites.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"15 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139212151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dahiana-Michelle Osorio-Aguilar, H. Saldarriaga-Noreña, M. Murillo-Tovar, Josefina Vergara-Sánchez, J. Ramírez-Aparicio, Lorena Magallón-Cacho, M. García-Betancourt
Wastewater-containing dyes are an environmental problem. The prime source of dye pollutants is the textile industry, such as paper manufacturing, food processing, leather, pigments, etc. Dye removal from wastewater using nanotechnology has received attention in recent decades thanks to efficient nanomaterials improving traditional technologies. In recent years, multiple research reports on carbon nanotubes for dye removal and photocatalytic dye degradation provided substantial insight into the comprehension of nanotechnology and remediation. This work presents a review and bibliometric analysis of carbon nanotubes for dye removal and photocatalytic dye degradation, which have an environmental impact today. The bibliometric study showed that the current research tendency on carbon nanotubes applied in dye removal and photocatalysis is still growing. According to research, this work observed that carbon nanotubes for dye removal exhibit high removal and efficient photocatalysis activity, indicating the functionality of nanotechnology for environmental remediation. The analysis of the parameters involved in the removal studies, such as temperature and pH, showed adsorption behavior. The photodegradation of methylene blue demonstrated the photocatalytic activity of carbon nanotubes attributed to the sp2 lattice of graphitic configuration.
{"title":"Adsorption and Photocatalytic Degradation of Methylene Blue in Carbon Nanotubes: A Review with Bibliometric Analysis","authors":"Dahiana-Michelle Osorio-Aguilar, H. Saldarriaga-Noreña, M. Murillo-Tovar, Josefina Vergara-Sánchez, J. Ramírez-Aparicio, Lorena Magallón-Cacho, M. García-Betancourt","doi":"10.3390/catal13121480","DOIUrl":"https://doi.org/10.3390/catal13121480","url":null,"abstract":"Wastewater-containing dyes are an environmental problem. The prime source of dye pollutants is the textile industry, such as paper manufacturing, food processing, leather, pigments, etc. Dye removal from wastewater using nanotechnology has received attention in recent decades thanks to efficient nanomaterials improving traditional technologies. In recent years, multiple research reports on carbon nanotubes for dye removal and photocatalytic dye degradation provided substantial insight into the comprehension of nanotechnology and remediation. This work presents a review and bibliometric analysis of carbon nanotubes for dye removal and photocatalytic dye degradation, which have an environmental impact today. The bibliometric study showed that the current research tendency on carbon nanotubes applied in dye removal and photocatalysis is still growing. According to research, this work observed that carbon nanotubes for dye removal exhibit high removal and efficient photocatalysis activity, indicating the functionality of nanotechnology for environmental remediation. The analysis of the parameters involved in the removal studies, such as temperature and pH, showed adsorption behavior. The photodegradation of methylene blue demonstrated the photocatalytic activity of carbon nanotubes attributed to the sp2 lattice of graphitic configuration.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139209354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Nogales-Delgado, C.M. Álvez-Medina, Vicente Montes, Juan Félix González
Hydrogen production from natural gas or biogas, at different purity levels, has emerged as an important technology with continuous development and improvement in order to stand for sustainable and clean energy. Regarding biogas, which can be obtained from multiple sources, hydrogen production through the steam reforming of methane is one of the most important methods for its energy use. In that sense, the role of catalysts to make the process more efficient is crucial, normally contributing to a higher hydrogen yield under milder reaction conditions in the final product. The aim of this review is to cover the main points related to these catalysts, as every aspect counts and has an influence on the use of these catalysts during this specific process (from the feedstocks used for biogas production or the biodigestion process to the purification of the hydrogen produced). Thus, a thorough review of hydrogen production through biogas steam reforming was carried out, with a special emphasis on the influence of different variables on its catalytic performance. Also, the most common catalysts used in this process, as well as the main deactivation mechanisms and their possible solutions are included, supported by the most recent studies about these subjects.
{"title":"A Review on the Use of Catalysis for Biogas Steam Reforming","authors":"S. Nogales-Delgado, C.M. Álvez-Medina, Vicente Montes, Juan Félix González","doi":"10.3390/catal13121482","DOIUrl":"https://doi.org/10.3390/catal13121482","url":null,"abstract":"Hydrogen production from natural gas or biogas, at different purity levels, has emerged as an important technology with continuous development and improvement in order to stand for sustainable and clean energy. Regarding biogas, which can be obtained from multiple sources, hydrogen production through the steam reforming of methane is one of the most important methods for its energy use. In that sense, the role of catalysts to make the process more efficient is crucial, normally contributing to a higher hydrogen yield under milder reaction conditions in the final product. The aim of this review is to cover the main points related to these catalysts, as every aspect counts and has an influence on the use of these catalysts during this specific process (from the feedstocks used for biogas production or the biodigestion process to the purification of the hydrogen produced). Thus, a thorough review of hydrogen production through biogas steam reforming was carried out, with a special emphasis on the influence of different variables on its catalytic performance. Also, the most common catalysts used in this process, as well as the main deactivation mechanisms and their possible solutions are included, supported by the most recent studies about these subjects.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"77 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139211442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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