Pub Date : 2024-10-19DOI: 10.1016/j.jcat.2024.115799
Hao Zhang, Qing Zhang, Guang-Ren Qian, Hong Liu, Yang Yue
In this research, a bimodal mesoporous AlMCM-41 (B-AM41) material was prepared and applied to support NiMo catalysts for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene. Additionally, catalysts supported on smaller and larger single-pore AlMCM-41 (S-AM41 and L-AM41) were also prepared as reference catalysts. Detailed characterizations show that the proportion, stacking degree, and length of the MoS2 active phase on the different catalysts are distinct. As a result, HDS evaluation indicates that the NiMo/B-AM41 catalyst exhibited better catalytic activity with a reaction rate constant of 10.4 × 10−8 mol g−1 s−1 and a turnover frequency of 7.0 × 10−4 s−1, significantly surpassing the S-AM41 and L-AM41 supported catalysts. The superior activity of the NiMo/B-AM41 catalyst can be attributed to a high sulfidation degree that provides sufficient highly dispersed type Ⅱ MoS2 phases with minimal stacking and moderate slab length. Moreover, the bimodal mesoporous structure promotes the diffusion of 4,6-DMDBT and benefits its contact with active sites.
{"title":"Bimodal mesoporous AlMCM-41 supported NiMo catalysts for efficient hydrodesulfurization of 4,6-dimethyldibenzothiophene","authors":"Hao Zhang, Qing Zhang, Guang-Ren Qian, Hong Liu, Yang Yue","doi":"10.1016/j.jcat.2024.115799","DOIUrl":"10.1016/j.jcat.2024.115799","url":null,"abstract":"<div><div>In this research, a bimodal mesoporous AlMCM-41 (B-AM41) material was prepared and applied to support NiMo catalysts for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene. Additionally, catalysts supported on smaller and larger single-pore AlMCM-41 (S-AM41 and L-AM41) were also prepared as reference catalysts. Detailed characterizations show that the proportion, stacking degree, and length of the MoS<sub>2</sub> active phase on the different catalysts are distinct. As a result, HDS evaluation indicates that the NiMo/B-AM41 catalyst exhibited better catalytic activity with a reaction rate constant of 10.4 × 10<sup>−8</sup> mol g<sup>−1</sup> s<sup>−1</sup> and a turnover frequency of 7.0 × 10<sup>−4</sup> s<sup>−1</sup>, significantly surpassing the S-AM41 and L-AM41 supported catalysts. The superior activity of the NiMo/B-AM41 catalyst can be attributed to a high sulfidation degree that provides sufficient highly dispersed type Ⅱ MoS<sub>2</sub> phases with minimal stacking and moderate slab length. Moreover, the bimodal mesoporous structure promotes the diffusion of 4,6-DMDBT and benefits its contact with active sites.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115799"},"PeriodicalIF":6.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.jcat.2024.115810
Rui Liu , Shangkun Li , Qian Chen , Dongxing Li , Jiasong Zhao , Chuang Li , Xiaoxia Gao , Wenping Zhao , Li Wang , Chong Peng , Annemie Bogaerts , Hongchen Guo , Yanhui Yi
We report one-step non-oxidative coupling of methane (CH4) to ethylene (C2H4) at atmospheric pressure and mild temperature (ca. 180–190 °C), by a combination of non-thermal plasma and a CuOx/CeO2 catalyst. The C2H4 selectivity gradually increases during an induction period. The corresponding spent catalysts at different stages were systematically characterized to disclose the evolution of the CuOx/CeO2 catalyst. During the induction period, the CuO/CeO2 catalyst was partially reduced to generate Cu+, Ce3+ and Ov species, which accompany the formation of Cu+-Ov-Ce3+ sites, as proven by XRD, HRTEM, XPS, Raman, EPR and H2-TPR. In addition, the C2H4 selectivity is proportional to the fraction of Cu+, Ce3+, Ov and Cu-O-Ce species, which indicates that Cu+-Ov-Ce3+ is the active site for non-oxidative coupling of CH4 to C2H4. Furthermore, in-situ FTIR results indicate that the Cu+-Ov-Ce3+ interface sites can promote dehydrogenation of CH3* (from CH4 plasma) to produce CH2* on the catalyst surface, which is the basic reason why CuOx/CeO2 acts as a catalyst in speeding up the non-oxidative coupling of CH4 for C2H4 production.
{"title":"Plasma-driven non-oxidative coupling of methane to ethylene and hydrogen at mild temperature over CuxO/CeO2 catalyst","authors":"Rui Liu , Shangkun Li , Qian Chen , Dongxing Li , Jiasong Zhao , Chuang Li , Xiaoxia Gao , Wenping Zhao , Li Wang , Chong Peng , Annemie Bogaerts , Hongchen Guo , Yanhui Yi","doi":"10.1016/j.jcat.2024.115810","DOIUrl":"10.1016/j.jcat.2024.115810","url":null,"abstract":"<div><div>We report one-step non-oxidative coupling of methane (CH<sub>4</sub>) to ethylene (C<sub>2</sub>H<sub>4</sub>) at atmospheric pressure and mild temperature (ca. 180–190 °C), by a combination of non-thermal plasma and a CuO<sub>x</sub>/CeO<sub>2</sub> catalyst. The C<sub>2</sub>H<sub>4</sub> selectivity gradually increases during an induction period. The corresponding spent catalysts at different stages were systematically characterized to disclose the evolution of the CuO<sub>x</sub>/CeO<sub>2</sub> catalyst. During the induction period, the CuO/CeO<sub>2</sub> catalyst was partially reduced to generate Cu<sup>+</sup>, Ce<sup>3+</sup> and O<sub>v</sub> species, which accompany the formation of Cu<sup>+</sup>-O<sub>v</sub>-Ce<sup>3+</sup> sites, as proven by XRD, HRTEM, XPS, Raman, EPR and H<sub>2</sub>-TPR. In addition, the C<sub>2</sub>H<sub>4</sub> selectivity is proportional to the fraction of Cu<sup>+</sup>, Ce<sup>3+</sup>, O<sub>v</sub> and Cu-O-Ce species, which indicates that Cu<sup>+</sup>-O<sub>v</sub>-Ce<sup>3+</sup> is the active site for non-oxidative coupling of CH<sub>4</sub> to C<sub>2</sub>H<sub>4</sub>. Furthermore, <em>in-situ</em> FTIR results indicate that the Cu<sup>+</sup>-O<sub>v</sub>-Ce<sup>3+</sup> interface sites can promote dehydrogenation of CH<sub>3</sub>* (from CH<sub>4</sub> plasma) to produce CH<sub>2</sub>* on the catalyst surface, which is the basic reason why CuO<sub>x</sub>/CeO<sub>2</sub> acts as a catalyst in speeding up the non-oxidative coupling of CH<sub>4</sub> for C<sub>2</sub>H<sub>4</sub> production.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115810"},"PeriodicalIF":6.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jcat.2024.115800
Hansel Montalvo-Castro, Álvaro Loaiza-Orduz, Randall J. Meyer, Craig Plaisance, David Hibbitts
This work employs density functional theory (DFT+U) calculations to explore initial C–H activations in C1–C3 alkanes on V2O5, MgV2O6 (meta-vanadate), Mg2V2O7 (pyro-vanadate), and Mg3V2O8 (ortho-vanadate) surfaces. These materials are selective catalysts for the oxidative dehydrogenation (ODH) of alkanes into alkenes, which offers practical and thermodynamic advantages over non-oxidative alkane dehydrogenation. The geometric and electronic properties that govern the reactivity of these materials, however, have not been explored by theory despite their importance in controlling rate determining alkane initial C–H activation during ODH catalysis. In this work, we explore fourteen low-energy surfaces of MgxV2Ox+5 (x = 0–3) exposing 64 distinct O atoms (reaction sites). C–H activation barriers are largest on Mg3V2O8, lower and similar for Mg2V2O7 and MgV2O6, and lowest for V2O5 surfaces; these predicted trends are consistent with measured ODH reactivity in earlier studies. Barriers are lowest (on average) when alkanes react with O atoms bound to a single V atom, with bridging O atoms having slightly higher barriers, and three-fold O atoms having the largest activation barriers. However, there is scattering within each subset indicating that factors beyond O-atom coordination have a significant role in the barriers. Vacancy formation energies (VFE) and the O 2p band energies were found to be weak descriptors of surface O reactivity for alkane activation barriers. Hydrogen addition energy (HAE) and methyl addition energy (MAE) values, in contrast, were found to correlate well with alkane activation barriers. MAE, however, outperforms HAE correlations because of the tendency of H* to form H-bonds with nearby surface O atoms, and those H-bonds are absent in C–H activation transition states causing scatter in the correlation of barriers with HAE. Constrained-orbital DFT methods were used to establish a theoretical thermochemical cycle that decouples surface reduction by CH3* into three components: surface distortion, orbital localization, and bond formation. These results give insights into how Mg:V ratios, surface structure (O-atom coordination), and reducibility (HAE, MAE) impact the reactivity of vanadium-based metal oxides toward alkane activation.
这项研究采用密度泛函理论（DFT+U）计算方法，探讨了 C1-C3 烷烃在 V2O5、MgV2O6（元钒酸盐）、Mg2V2O7（焦钒酸盐）和 Mg3V2O8（正钒酸盐）表面上的初始 C-H 活化。这些材料是烷烃氧化脱氢（ODH）成烯烃的选择性催化剂，与非氧化烷烃脱氢相比，具有实用性和热力学优势。然而，尽管在 ODH 催化过程中，决定烷烃初始 C-H 活化速率的几何和电子特性非常重要，但理论界尚未对这些材料反应性的几何和电子特性进行探讨。在这项研究中，我们探索了 MgxV2Ox+5 (x = 0-3)的十四个低能表面，这些表面暴露了 64 个不同的 O 原子（反应位点）。Mg3V2O8 的 C-H 活化障碍最大，Mg2V2O7 和 MgV2O6 的 C-H 活化障碍较低且相似，V2O5 表面的 C-H 活化障碍最低；这些预测趋势与早期研究中测得的 ODH 反应性一致。当烷烃与结合在单个 V 原子上的 O 原子反应时，反应壁垒最低（平均值），桥接 O 原子的反应壁垒略高，而三重 O 原子的活化壁垒最大。不过，每个子集内部都存在散射现象，这表明 O 原子配位以外的因素对活化势垒也有重要影响。研究发现，空位形成能（VFE）和 O 2p 带能是表面 O 反应性对烷烃活化势垒的微弱描述。相反，氢加成能（HAE）和甲基加成能（MAE）值与烷烃活化势垒有很好的相关性。然而，MAE 的相关性优于 HAE，这是因为 H* 倾向于与附近的表面 O 原子形成 H 键，而这些 H 键在 C-H 活化转变态中不存在，从而导致活化势垒与 HAE 的相关性分散。利用受限轨道 DFT 方法建立了一个理论热化学循环，将 CH3* 的表面还原分解为三个部分：表面变形、轨道定位和键的形成。这些结果让我们深入了解了镁:钒比、表面结构（O 原子配位）和还原性（HAE、MAE）如何影响钒基金属氧化物对烷烃活化的反应性。
{"title":"Electronic and geometric features controlling the reactivity of Mg-vanadate and V2O5 surfaces toward the initial C–H activation of C1–C3 alkanes – A DFT+U study","authors":"Hansel Montalvo-Castro, Álvaro Loaiza-Orduz, Randall J. Meyer, Craig Plaisance, David Hibbitts","doi":"10.1016/j.jcat.2024.115800","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115800","url":null,"abstract":"This work employs density functional theory (DFT+U) calculations to explore initial C–H activations in C<sub>1</sub>–C<sub>3</sub> alkanes on V<sub>2</sub>O<sub>5</sub>, MgV<sub>2</sub>O<sub>6</sub> (meta-vanadate), Mg<sub>2</sub>V<sub>2</sub>O<sub>7</sub> (pyro-vanadate), and Mg<sub>3</sub>V<sub>2</sub>O<sub>8</sub> (ortho-vanadate) surfaces. These materials are selective catalysts for the oxidative dehydrogenation (ODH) of alkanes into alkenes, which offers practical and thermodynamic advantages over non-oxidative alkane dehydrogenation. The geometric and electronic properties that govern the reactivity of these materials, however, have not been explored by theory despite their importance in controlling rate determining alkane initial C–H activation during ODH catalysis. In this work, we explore fourteen low-energy surfaces of Mg<em><sub>x</sub></em>V<sub>2</sub>O<em><sub>x</sub></em><sub>+5</sub> (<em>x</em> = 0–3) exposing 64 distinct O atoms (reaction sites). C–H activation barriers are largest on Mg<sub>3</sub>V<sub>2</sub>O<sub>8</sub>, lower and similar for Mg<sub>2</sub>V<sub>2</sub>O<sub>7</sub> and MgV<sub>2</sub>O<sub>6</sub>, and lowest for V<sub>2</sub>O<sub>5</sub> surfaces; these predicted trends are consistent with measured ODH reactivity in earlier studies. Barriers are lowest (on average) when alkanes react with O atoms bound to a single V atom, with bridging O atoms having slightly higher barriers, and three-fold O atoms having the largest activation barriers. However, there is scattering within each subset indicating that factors beyond O-atom coordination have a significant role in the barriers. Vacancy formation energies (VFE) and the O 2p band energies were found to be weak descriptors of surface O reactivity for alkane activation barriers. Hydrogen addition energy (HAE) and methyl addition energy (MAE) values, in contrast, were found to correlate well with alkane activation barriers. MAE, however, outperforms HAE correlations because of the tendency of H* to form H-bonds with nearby surface O atoms, and those H-bonds are absent in C–H activation transition states causing scatter in the correlation of barriers with HAE. Constrained-orbital DFT methods were used to establish a theoretical thermochemical cycle that decouples surface reduction by CH<sub>3</sub>* into three components: surface distortion, orbital localization, and bond formation. These results give insights into how Mg:V ratios, surface structure (O-atom coordination), and reducibility (HAE, MAE) impact the reactivity of vanadium-based metal oxides toward alkane activation.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"40 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jcat.2024.115807
Yuting Wang , Mengxiang Wang , Xuya Zhang , Xinru Pan , Yongpeng Cui , Daoqing Liu , Yajun Wang , Wenqing Yao
In addressing the industrial need for a simple, equipment-minimal, and non-toxic method of in-situ hydrogen peroxide (H2O2) production, this paper presents a cost-effective, environmentally friendly photocatalyst. Our design strategy focuses on the dual-element doping of phosphorus and sodium into graphitic carbon nitride (g-C3N4), chosen to synergistically enhance photocatalytic performance. This approach yields a notable H2O2 production concentration of 3001.64 μmol·g−1·L-1 within 100 min, using isopropanol as a sacrificial agent, which was 61-fold increase compared to bulk g-C3N4. Density Functional Theory (DFT) calculations were performed to elucidate the alterations in the band structure of the catalyst induced by dual-element doping, which consequentially engendered an asymmetric intrinsic electric field. Additionally, oxygen’s transition state affinity due to phosphorus doping was also investigated to reveal the mechanisms of synergistic catalysis. This development contributes to meeting industrial demands for pollutant degradation via Fenton processes and presents a sustainable alternative to traditional H2O2 production methods.
{"title":"Synergistic regulation of g-C3N4 band structure by phosphorus and sodium doping to enhance photocatalytic hydrogen peroxide production efficiency","authors":"Yuting Wang , Mengxiang Wang , Xuya Zhang , Xinru Pan , Yongpeng Cui , Daoqing Liu , Yajun Wang , Wenqing Yao","doi":"10.1016/j.jcat.2024.115807","DOIUrl":"10.1016/j.jcat.2024.115807","url":null,"abstract":"<div><div>In addressing the industrial need for a simple, equipment-minimal, and non-toxic method of in-situ hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production, this paper presents a cost-effective, environmentally friendly photocatalyst. Our design strategy focuses on the dual-element doping of phosphorus and sodium into graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>), chosen to synergistically enhance photocatalytic performance. This approach yields a notable H<sub>2</sub>O<sub>2</sub> production concentration of 3001.64 μmol·g<sup>−1</sup>·L<sup>-1</sup> within 100 min, using isopropanol as a sacrificial agent, which was 61-fold increase compared to bulk g-C<sub>3</sub>N<sub>4</sub>. Density Functional Theory (DFT) calculations were performed to elucidate the alterations in the band structure of the catalyst induced by dual-element doping, which consequentially engendered an asymmetric intrinsic electric field. Additionally, oxygen’s transition state affinity due to phosphorus doping was also investigated to reveal the mechanisms of synergistic catalysis. This development contributes to meeting industrial demands for pollutant degradation via Fenton processes and presents a sustainable alternative to traditional H<sub>2</sub>O<sub>2</sub> production methods.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115807"},"PeriodicalIF":6.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.jcat.2024.115797
Ernestina García-Quinto , Raquel Aranda-Cañada , Jose M. Guisan , Gloria Fernandez-Lorente
Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, is crucial for the normal development and function of the brain. Its production can be achieved through the partial hydrolysis of DHA-rich triglycerides catalyzed by lipases, particularly from fish oils. In this work, the characterization of anchovy oil capsules revealed that they offer a pure and concentrated source of DHA, with more than 90 % of the oil in the form of triglycerides. Therefore, the hydrolysis reaction was studied with the aim of releasing 100 % of the DHA present in this oil, using different immobilized lipases with maximum enzyme loading on the hydrophobic support Immobeads-C18. The study’s results revealed that our immobilization strategy through hydrophobic adsorption improved the catalytic properties of activity and selectivity of the TLL lipase compared to other biocatalysts described in the literature. Additionally, complete hydrolysis of the oil was achieved in just 24 h with the NS40-C18 derivative, which could be reused up to 6 cycles without loss of activity.
{"title":"Production of docosahexaenoic acid through enzymatic hydrolysis of Omega-3 rich oil","authors":"Ernestina García-Quinto , Raquel Aranda-Cañada , Jose M. Guisan , Gloria Fernandez-Lorente","doi":"10.1016/j.jcat.2024.115797","DOIUrl":"10.1016/j.jcat.2024.115797","url":null,"abstract":"<div><div>Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, is crucial for the normal development and function of the brain. Its production can be achieved through the partial hydrolysis of DHA-rich triglycerides catalyzed by lipases, particularly from fish oils. In this work, the characterization of anchovy oil capsules revealed that they offer a pure and concentrated source of DHA, with more than 90 % of the oil in the form of triglycerides. Therefore, the hydrolysis reaction was studied with the aim of releasing 100 % of the DHA present in this oil, using different immobilized lipases with maximum enzyme loading on the hydrophobic support Immobeads-C18. The study’s results revealed that our immobilization strategy through hydrophobic adsorption improved the catalytic properties of activity and selectivity of the TLL lipase compared to other biocatalysts described in the literature. Additionally, complete hydrolysis of the oil was achieved in just 24 h with the NS40-C18 derivative, which could be reused up to 6 cycles without loss of activity.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115797"},"PeriodicalIF":6.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.jcat.2024.115796
Pranit Samanta, Mohd. Ussama, Gourav Shrivastav, M. Ali Haider, K.K. Pant, Manjesh Kumar
Tuning of Al sites through spatial and geometric distribution is a novel pursuit for deterministic catalytic performance. To design an efficient Zeolite Beta for phenol alkylation with optimal physicochemical attributes, we conducted a systematic study with a series of dicarboxylic acids to selectively extract the framework and/or non-framework Aluminium. Herein, the post-synthetic treatment resulted in dealuminated catalysts of silicon-to-aluminum ratio ∼15–53. Extensive Al and Si NMR studies glean the selective extraction of aluminum from the zeolitic framework along with recomposition in T sites. The potency study alludes to the convoluted role of pH, chelating ability, and/or site accessibility for complexation. The differentiated Al extraction results in the emergence of unique super-strong acid sites. The novelty of our approach was established using phenol alkylation with cyclohexanol wherein we observed the highest conversion and desired CC alkylated product formation for the malonic acid-treated Zeolite Beta.
通过空间和几何分布调节铝位点是实现确定性催化性能的一种新方法。为了设计出具有最佳物理化学属性的高效沸石 Beta 用于苯酚烷基化，我们使用一系列二羧酸进行了系统研究，以选择性地提取框架和/或非框架铝。在这里，后合成处理产生了硅铝比为 15-53 的脱铝催化剂。大量的铝和硅核磁共振研究表明，铝从沸石框架中被选择性地提取出来，并在 T 位点上重新合成。效力研究表明，pH 值、螯合能力和/或络合位点的可及性具有复杂的作用。不同的铝萃取导致了独特的超强酸性位点的出现。我们使用苯酚与环己醇进行烷基化，观察到丙二酸处理的沸石 Beta 转化率最高，并形成了所需的 CC 烷基化产物，这证明了我们的方法具有新颖性。
{"title":"Selective dealumination of large pore Zeolite Beta for effective Brønsted acid site utilization","authors":"Pranit Samanta, Mohd. Ussama, Gourav Shrivastav, M. Ali Haider, K.K. Pant, Manjesh Kumar","doi":"10.1016/j.jcat.2024.115796","DOIUrl":"10.1016/j.jcat.2024.115796","url":null,"abstract":"<div><div>Tuning of Al sites through spatial and geometric distribution is a novel pursuit for deterministic catalytic performance. To design an efficient Zeolite Beta for phenol alkylation with optimal physicochemical attributes, we conducted a systematic study with a series of dicarboxylic acids to selectively extract the framework and/or non-framework Aluminium. Herein, the post-synthetic treatment resulted in dealuminated catalysts of silicon-to-aluminum ratio ∼15–53. Extensive Al and Si NMR studies glean the selective extraction of aluminum from the zeolitic framework along with recomposition in T sites. The potency study alludes to the convoluted role of pH, chelating ability, and/or site accessibility for complexation. The differentiated Al extraction results in the emergence of unique super-strong acid sites. The novelty of our approach was established using phenol alkylation with cyclohexanol wherein we observed the highest conversion and desired C<img>C alkylated product formation for the malonic acid-treated Zeolite Beta.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115796"},"PeriodicalIF":6.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.jcat.2024.115792
Songgang Huang , Yan Wang , Si Si , Mei Yan , Weimin Zhang , Wenhua Ji , Jie Chen , Wonwoo Nam , Bin Wang
High-valent metal-oxo species have been invoked as key intermediates in enzymatic and biomimetic oxidation reactions. The generation of high-valent metal-oxo species using water (H2O) as an oxygen source represents one of the most environmentally friendly approaches in developing biologically inspired oxidation catalysis. Herein, we report the electrochemical oxidation of benzylic C−H bonds and alcohols utilizing a mononuclear nonheme iron(III)-monoamidate complex [FeIII(dpaq)(H2O)]2+ (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate) as a catalyst and H2O as an oxygen source. Selective benzylic C−H bond oxidation of alkanes to ketones was achieved in 43–85 % yields, and primary and secondary alcohols were converted to the corresponding aldehydes and ketones, respectively, in 46–95 % yields. The generation of an iron(V)-oxo species [FeV(O)(dpaq)]2+ from proton-coupled electron-transfer (PCET) oxidation of the iron(III) aqua complex [FeIII(dpaq)(H2O)]2+ was evidenced by cyclic voltammetry analysis; the iron(V)-oxo species [FeV(O)(dpaq)]2+ was recently detected using transient absorption spectroscopy in water oxidation reactions. Mechanistic studies revealed that electrochemical oxidation of alcohols catalyzed by FeIII(dpaq) is a two-electron oxidation process, hydrogen-atom transfer (HAT) from the α-C−H bond of alcohols by iron(V)-oxo species is the rate-determining step, and there is a remarkable charge transfer from the highly electrophilic iron(V)-oxo species to the alcohols in the HAT step. This research paves a significant groundwork aimed at developing electrochemically driven biomimetic asymmetric oxidation reactions catalyzed by nonheme metal complexes supported by chiral ligands.
{"title":"Electrochemically driven nonheme iron complex-catalyzed oxidation reactions using water as an oxygen source","authors":"Songgang Huang , Yan Wang , Si Si , Mei Yan , Weimin Zhang , Wenhua Ji , Jie Chen , Wonwoo Nam , Bin Wang","doi":"10.1016/j.jcat.2024.115792","DOIUrl":"10.1016/j.jcat.2024.115792","url":null,"abstract":"<div><div>High-valent metal-oxo species have been invoked as key intermediates in enzymatic and biomimetic oxidation reactions. The generation of high-valent metal-oxo species using water (H<sub>2</sub>O) as an oxygen source represents one of the most environmentally friendly approaches in developing biologically inspired oxidation catalysis. Herein, we report the electrochemical oxidation of benzylic C−H bonds and alcohols utilizing a mononuclear nonheme iron(III)-monoamidate complex [Fe<sup>III</sup>(dpaq)(H<sub>2</sub>O)]<sup>2+</sup> (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-<em>N</em>-quinolin-8-yl-acetamidate) as a catalyst and H<sub>2</sub>O as an oxygen source. Selective benzylic C−H bond oxidation of alkanes to ketones was achieved in 43–85 % yields, and primary and secondary alcohols were converted to the corresponding aldehydes and ketones, respectively, in 46–95 % yields. The generation of an iron(V)-oxo species [Fe<sup>V</sup>(O)(dpaq)]<sup>2+</sup> from proton-coupled electron-transfer (PCET) oxidation of the iron(III) aqua complex [Fe<sup>III</sup>(dpaq)(H<sub>2</sub>O)]<sup>2+</sup> was evidenced by cyclic voltammetry analysis; the iron(V)-oxo species [Fe<sup>V</sup>(O)(dpaq)]<sup>2+</sup> was recently detected using transient absorption spectroscopy in water oxidation reactions. Mechanistic studies revealed that electrochemical oxidation of alcohols catalyzed by Fe<sup>III</sup>(dpaq) is a two-electron oxidation process, hydrogen-atom transfer (HAT) from the α-C−H bond of alcohols by iron(V)-oxo species is the rate-determining step, and there is a remarkable charge transfer from the highly electrophilic iron(V)-oxo species to the alcohols in the HAT step. This research paves a significant groundwork aimed at developing electrochemically driven biomimetic asymmetric oxidation reactions catalyzed by nonheme metal complexes supported by chiral ligands.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115792"},"PeriodicalIF":6.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.jcat.2024.115798
Junjie Shi , Paulina Pršlja , Milla Suominen , Benjin Jin , Jouko Lahtinen , Lilian Moumaneix , Xiangze Kong , Tanja Kallio
BiOx shows promising selectivity in catalyzing the electrochemical reduction of CO2 to formate, but the process suffers from high overpotential and a low rate. Moreover, the active sites are still ambiguous under electrochemical conditions. Herein, we introduce Mn-doping to enhance the activity of binder-free Bi2O3 and elaborate on active sites through in situ Raman and density functional theory (DFT) analyses. The Mn-doped Bi2O3 transforms to Mn-doped Bi2(CO3)O2 in KHCO3 and subsequently reduces to Mn-modified metallic Bi under cathodic potentials. The undoped Bi2O3 is found to follow the same phase transitions but at a different rate. The DFT analyzes the impact of doping the Bi(012) with Mn and indicates significantly improved selectivity for formate generation. Further, the importance of the substrate’s hydrophobicity for long-term stability is demonstrated. This study offers in-depth insights into the design and understanding of doped BiOx-based electrodes for CO2 reduction.
{"title":"Mn-doped Bi2O3 grown on PTFE-treated carbon paper for electrochemical CO2-to-formate production","authors":"Junjie Shi , Paulina Pršlja , Milla Suominen , Benjin Jin , Jouko Lahtinen , Lilian Moumaneix , Xiangze Kong , Tanja Kallio","doi":"10.1016/j.jcat.2024.115798","DOIUrl":"10.1016/j.jcat.2024.115798","url":null,"abstract":"<div><div>BiO<sub>x</sub> shows promising selectivity in catalyzing the electrochemical reduction of CO<sub>2</sub> to formate, but the process suffers from high overpotential and a low rate. Moreover, the active sites are still ambiguous under electrochemical conditions. Herein, we introduce Mn-doping to enhance the activity of binder-free Bi<sub>2</sub>O<sub>3</sub> and elaborate on active sites through <em>in situ</em> Raman and density functional theory (DFT) analyses. The Mn-doped Bi<sub>2</sub>O<sub>3</sub> transforms to Mn-doped Bi<sub>2</sub>(CO<sub>3</sub>)O<sub>2</sub> in KHCO<sub>3</sub> and subsequently reduces to Mn-modified metallic Bi under cathodic potentials. The undoped Bi<sub>2</sub>O<sub>3</sub> is found to follow the same phase transitions but at a different rate. The DFT analyzes the impact of doping the Bi(012) with Mn and indicates significantly improved selectivity for formate generation. Further, the importance of the substrate’s hydrophobicity for long-term stability is demonstrated. This study offers in-depth insights into the design and understanding of doped BiO<sub>x</sub>-based electrodes for CO<sub>2</sub> reduction.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115798"},"PeriodicalIF":6.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.jcat.2024.115793
Yue Zhang , Rongrong Zhang , Guozhu Liu , Li Wang , Zhiyong Pan
Core-shell Ru@Pd/SBA-15 catalysts with various atomic layer numbers of Pd were prepared by changing the Pd/Ru ratio and Pd coating temperature. The results of characterizations show that the compressive strain of Pd atoms and electron transfer from Ru to Pd result in a downward shift in the d-band center of core–shell catalysts. Density functional theory calculations further reveal that the reduced d-band center of Pd via strain and electronic effects weakens the adsorption ability of Pd. A roughly volcano-shaped correlation between the d-band center and 2-ethyl-anthraquinone (EAQ) hydrogenation activity is experimentally observed. The catalyst with Pd shell of 2 atomic layers provides medium adsorption strength for EAQ and hydrogenated product, thereby exhibiting the highest activity of 0.37 molH2·gMet−1·min−1, with a selectivity of 97.3%. This work provides a facile strategy for optimizing hydrogenation performance by modulating the strain and electron effects between the Ru core and Pd shell through regulating the number of shell layers.
{"title":"Boosting the catalytic performance of core-shell structured Ru@Pd/SBA-15 in 2-ethyl-anthraquinone hydrogenation by tuning d-band center","authors":"Yue Zhang , Rongrong Zhang , Guozhu Liu , Li Wang , Zhiyong Pan","doi":"10.1016/j.jcat.2024.115793","DOIUrl":"10.1016/j.jcat.2024.115793","url":null,"abstract":"<div><div>Core-shell Ru@Pd/SBA-15 catalysts with various atomic layer numbers of Pd were prepared by changing the Pd/Ru ratio and Pd coating temperature. The results of characterizations show that the compressive strain of Pd atoms and electron transfer from Ru to Pd result in a downward shift in the <em>d</em>-band center of core–shell catalysts. Density functional theory calculations further reveal that the reduced <em>d</em>-band center of Pd <em>via</em> strain and electronic effects weakens the adsorption ability of Pd. A roughly volcano-shaped correlation between the <em>d</em>-band center and 2-ethyl-anthraquinone (EAQ) hydrogenation activity is experimentally observed. The catalyst with Pd shell of 2 atomic layers provides medium adsorption strength for EAQ and hydrogenated product, thereby exhibiting the highest activity of 0.37 molH<sub>2</sub>·gMet<sup>−1</sup>·min<sup>−1</sup>, with a selectivity of 97.3%. This work provides a facile strategy for optimizing hydrogenation performance by modulating the strain and electron effects between the Ru core and Pd shell through regulating the number of shell layers.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115793"},"PeriodicalIF":6.5,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-14DOI: 10.1016/j.jcat.2024.115794
Wei Zheng , Chao Sun , Zejian Dong , Lifeng Zhang , Xi Wang , Langli Luo
The Cu/ZnO/Al2O3 is a typical industrial catalyst for water–gas-shift reaction and methanol synthesis, and is also gaining momentum in CO2 hydrogenation reaction. The dynamic evolution of the phases and microstructures of the precursor of this catalyst leads to a notable synergistic effect that defines its overall catalytic function and performance. To gain insights into the role and interaction between the relevant precursors, we compared Cu/ZnO/Al2O3 catalysts using a conventional co-precipitation and a fractional precipitation method, where the latter one shows an enhanced Cu/ZnOx interface due to a thorough and strong interaction between two components in the precursor. The ZnOx decoration on Cu with unsaturated Znδ+ species boosted the methanol formation to a rate of 508 gCH3OH‧kgcat−1‧h−1 with 58 % selectivity at 513 K and 3 MPa. This work provides mechanistic insights into the synergistic interplay between the involved phases in the Cu/ZnO/Al2O3 catalyst.
{"title":"Enhanced CO2 hydrogenation reaction by Tuning interfacial Cu/ZnOx through synergistic interactions in the precursors","authors":"Wei Zheng , Chao Sun , Zejian Dong , Lifeng Zhang , Xi Wang , Langli Luo","doi":"10.1016/j.jcat.2024.115794","DOIUrl":"10.1016/j.jcat.2024.115794","url":null,"abstract":"<div><div>The Cu/ZnO/Al<sub>2</sub>O<sub>3</sub> is a typical industrial catalyst for water–gas-shift reaction and methanol synthesis, and is also gaining momentum in CO<sub>2</sub> hydrogenation reaction. The dynamic evolution of the phases and microstructures of the precursor of this catalyst leads to a notable synergistic effect that defines its overall catalytic function and performance. To gain insights into the role and interaction between the relevant precursors, we compared Cu/ZnO/Al<sub>2</sub>O<sub>3</sub> catalysts using a conventional co-precipitation and a fractional precipitation method, where the latter one shows an enhanced Cu/ZnO<sub>x</sub> interface due to a thorough and strong interaction between two components in the precursor. The ZnO<sub>x</sub> decoration on Cu with unsaturated Zn<sup>δ+</sup> species boosted the methanol formation to a rate of 508 g<sub>CH3OH</sub>‧kg<sub>cat</sub><sup>−1</sup>‧h<sup>−1</sup> with 58 % selectivity at 513 K and 3 MPa. This work provides mechanistic insights into the synergistic interplay between the involved phases in the Cu/ZnO/Al<sub>2</sub>O<sub>3</sub> catalyst.</div></div>","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"440 ","pages":"Article 115794"},"PeriodicalIF":6.5,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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