Pub Date : 2024-12-24DOI: 10.1016/j.jcat.2024.115911
Wenting Fang, Yuyan Zhang, Liqun Kang, Serena DeBeer, Walter Leitner, Alexis Bordet, Anders Riisager
Modified aluminum phosphate (APO-5) proved suitable as zeotype support for the preparation of imidazolium-based supported ionic liquid phase material, i.e. SILP(APO-5). The successful chemisorption of ionic liquid-like modifiers at the APO-5 surface was demonstrated by solid state 31P and 13C nuclear magnetic resonance (NMR) spectroscopy. The immobilization of Ru nanoparticles (NPs) on SILP(APO-5) was achieved following an organometallic approach, producing well-dispersed Ru NPs with a mean average size of 1.4 nm on the support. The resulting Ru@SILP(APO-5) material was thoroughly characterized using multiple techniques, e.g., solid state NMR, transmission electron microscopy (TEM), infrared (IR) spectroscopy, X-ray absorption spectroscopy (XAS), and applied as a catalyst for the hydrogenation of biomass-derived furfural acetone with molecular hydrogen. The ionic liquid-like layer was found beneficial for the stabilization of the Ru NPs as well as of the APO-5 material. A temperature-controlled selectivity switch between olefinic, carbonyl or furan ring hydrogenation could be achieved with this new material with the APO-5 facilitating activation of the olefinic bond, while the carbonyl bond was remarkably deactivated. The demonstrated suitability of aluminum phosphate materials to produce molecularly modified surfaces offers a new control parameter for the systematic design and optimization of zeotype-based catalysts.
{"title":"Molecularly modified aluminum phosphates as support materials for Ru nanoparticles in selective hydrogenation","authors":"Wenting Fang, Yuyan Zhang, Liqun Kang, Serena DeBeer, Walter Leitner, Alexis Bordet, Anders Riisager","doi":"10.1016/j.jcat.2024.115911","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115911","url":null,"abstract":"Modified aluminum phosphate (APO-5) proved suitable as zeotype support for the preparation of imidazolium-based supported ionic liquid phase material, i.e. SILP(APO-5). The successful chemisorption of ionic liquid-like modifiers at the APO-5 surface was demonstrated by solid state <sup>31</sup>P and <sup>13</sup>C nuclear magnetic resonance (NMR) spectroscopy. The immobilization of Ru nanoparticles (NPs) on SILP(APO-5) was achieved following an organometallic approach, producing well-dispersed Ru NPs with a mean average size of 1.4 nm on the support. The resulting Ru@SILP(APO-5) material was thoroughly characterized using multiple techniques, e.g., solid state NMR, transmission electron microscopy (TEM), infrared (IR) spectroscopy, X-ray absorption spectroscopy (XAS), and applied as a catalyst for the hydrogenation of biomass-derived furfural acetone with molecular hydrogen. The ionic liquid-like layer was found beneficial for the stabilization of the Ru NPs as well as of the APO-5 material. A temperature-controlled selectivity switch between olefinic, carbonyl or furan ring hydrogenation could be achieved with this new material with the APO-5 facilitating activation of the olefinic bond, while the carbonyl bond was remarkably deactivated. The demonstrated suitability of aluminum phosphate materials to produce molecularly modified surfaces offers a new control parameter for the systematic design and optimization of zeotype-based catalysts.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"32 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879902","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}
The selective catalytic reduction (SCR) of NOx, utilizing carbon monoxide (CO) and ammonia (NH3), is recognized as an effective approach for NOx abatement. During the SCR process, the appropriate pretreatment of catalysts can significantly enhance their surface and interfacial structures, thereby improving their activity, selectivity, and stability. This review begins with the reaction mechanisms of CO-SCR and NH3-SCR, followed by an introduction to various pretreatment strategies that can enhance the performance of catalysts employed in these two reactions. An in-depth discussion is provided regarding how different pretreatment methods influence the active structure of catalysts, the key steps of the reactions, and the overall catalytic performance. Subsequently, a comparative analysis of the pretreatment strategies employed for both reactions is presented, highlighting their similarities and differences, thereby elucidating the essence of pretreatment techniques. Lastly, the paper identifies the current challenges encountered in the field of pretreatment and proposes potential directions for future development. This work aims to offer theoretical insights that may inspire innovative pretreatment strategies in CO-SCR and NH3-SCR among researchers and engineers.
{"title":"Pretreatment techniques in CO-SCR and NH3-SCR: Status, challenges, and perspectives","authors":"Guiyao Dai, Botao Liu, Ruijing Wang, Huanli Wang, Yaxin Miao, Shujun Hou, Dianxing Lian, Mohaoyang Chen, Chenxi Li, Zhijin Zhang, Bushi Dang, Jingchun Liu, Weiwei Zhang, Ke Wu, Honggen Peng, Guofeng Zhao, Yuxi Liu, Yongjun Ji","doi":"10.1016/j.jcat.2024.115925","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115925","url":null,"abstract":"The selective catalytic reduction (SCR) of NO<sub>x</sub>, utilizing carbon monoxide (CO) and ammonia (NH<sub>3</sub>), is recognized as an effective approach for NO<sub>x</sub> abatement. During the SCR process, the appropriate pretreatment of catalysts can significantly enhance their surface and interfacial structures, thereby improving their activity, selectivity, and stability. This review begins with the reaction mechanisms of CO-SCR and NH<sub>3</sub>-SCR, followed by an introduction to various pretreatment strategies that can enhance the performance of catalysts employed in these two reactions. An in-depth discussion is provided regarding how different pretreatment methods influence the active structure of catalysts, the key steps of the reactions, and the overall catalytic performance. Subsequently, a comparative analysis of the pretreatment strategies employed for both reactions is presented, highlighting their similarities and differences, thereby elucidating the essence of pretreatment techniques. Lastly, the paper identifies the current challenges encountered in the field of pretreatment and proposes potential directions for future development. This work aims to offer theoretical insights that may inspire innovative pretreatment strategies in CO-SCR and NH<sub>3</sub>-SCR among researchers and engineers.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"26 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879899","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 : 2024-12-24DOI: 10.1016/j.jcat.2024.115923
Xiuyi Wang, Hongbo Zhang
In this study, we investigate the effect of interfacial structure on the methanol steam reforming (MSR) reaction by systematically varying the transition metals (Pt, Ru, Rh, Pd, and Ir) over a NiAl2O4 support. At similar methanol conversions at ∼ 5 %, H2 formation exhibits superior reaction performance at ∼ 0.14 molH2·molmetal-1·s−1 over Pt/NiAl2O4 than any other counter parts, which was attributed to the enhanced ability in tolerance of CO from and catalytic surface and the greater ability in CH3O– activation with the activation energies of MSR, MD, and WGS at 70 kJ/mol, 79 kJ/mol, and 97 kJ/mol, respectively, which is obviously smaller than the other transition metal catalysts. More importantly, the higher reduction degree of Pt and more stabilized transition state along methanol activation might be additional reasons for this superior reaction performance on H2 formation.
{"title":"The nature of interfacial catalysis over Pt/NiAl2O4: Effects of metal identity and CO tolerance in hydrogen production from methanol reforming reaction","authors":"Xiuyi Wang, Hongbo Zhang","doi":"10.1016/j.jcat.2024.115923","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115923","url":null,"abstract":"In this study, we investigate the effect of interfacial structure on the methanol steam reforming (MSR) reaction by systematically varying the transition metals (Pt, Ru, Rh, Pd, and Ir) over a NiAl<sub>2</sub>O<sub>4</sub> support. At similar methanol conversions at ∼ 5 %, H<sub>2</sub> formation exhibits superior reaction performance at ∼ 0.14 mol<sub>H2</sub>·mol<sub>metal</sub><sup>-1</sup>·s<sup>−1</sup> over Pt/NiAl<sub>2</sub>O<sub>4</sub> than any other counter parts, which was attributed to the enhanced ability in tolerance of CO from and catalytic surface and the greater ability in CH<sub>3</sub>O– activation with the activation energies of MSR, MD, and WGS at 70 kJ/mol, 79 kJ/mol, and 97 kJ/mol, respectively, which is obviously smaller than the other transition metal catalysts. More importantly, the higher reduction degree of Pt and more stabilized transition state along methanol activation might be additional reasons for this superior reaction performance on H<sub>2</sub> formation.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"25 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879898","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 : 2024-12-24DOI: 10.1016/j.jcat.2024.115927
Ahmed Sajid, Julien Devos, Sven Robijns, Thibaut Donckels, Ibrahim Khalil, Michiel Dusselier
The tandem conversion of carbon dioxide to olefins (CTO) via methanol over a combination of metal oxide plus zeolite catalysts is a considerable alternative to fossil-based routes to light olefins. Here, AEI type small pore zeolites i.e., SSZ-39 and SAPO-18, in combination with ZnZrOx, are put forward as the excellent tandem catalysts for CTO. We deconvolute the influences of acidity and framework composition on the product selectivity and productivity of light olefins. Post-synthesis steaming was utilized as a strategy to tune the acidity and structure of the zeolites. SSZ-39 steamed at 750 °C showed the highest olefin/paraffin ratio (O/P = 2.1) as compared to the unsteamed SSZ-39 with an O/P ratio of 0.2. In contrast, SAPO-18 steamed at 650 °C showed a maximum O/P ratio of 2.1, whereas steaming at higher temperatures resulted in decreased activities. Propylene was observed as the major olefin for both SSZ-39 and SAPO-18 in line with the cage-defining ring size of AEI. It was found through FT-IR and NH3-TPD that the increase in the steaming temperature decreases the Brønsted acidity of SSZ-39 which inhibits both the secondary hydrogenation of olefins to paraffins and the methanol-assisted hydrogen transfer reaction. Coupling of CO2 to methanol (CTM) with methanol to olefins (MTO) reaction increased the CO2 conversion and selectivity towards methanol equivalents by suppressing CO production in tandem systems as compared to the sole CTM reaction. The effect of catalyst bed configuration on product selectivity over the best performing catalyst was also studied, and the highest O/P ratio (3.7) was observed for a powder mixed system opposed to dual bed or mixed bed systems.
{"title":"Role of coupling and zeolite acidity in the methanol-mediated CO2 conversion to olefins over ZnZrOx-AEI zeolite tandem catalysis","authors":"Ahmed Sajid, Julien Devos, Sven Robijns, Thibaut Donckels, Ibrahim Khalil, Michiel Dusselier","doi":"10.1016/j.jcat.2024.115927","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115927","url":null,"abstract":"The tandem conversion of carbon dioxide to olefins (CTO) via methanol over a combination of metal oxide plus zeolite catalysts is a considerable alternative to fossil-based routes to light olefins. Here, AEI type small pore zeolites i.e., SSZ-39 and SAPO-18, in combination with ZnZrOx, are put forward as the excellent tandem catalysts for CTO. We deconvolute the influences of acidity and framework composition on the product selectivity and productivity of light olefins. Post-synthesis steaming was utilized as a strategy to tune the acidity and structure of the zeolites. SSZ-39 steamed at 750 °C showed the highest olefin/paraffin ratio (O/P = 2.1) as compared to the unsteamed SSZ-39 with an O/P ratio of 0.2. In contrast, SAPO-18 steamed at 650 °C showed a maximum O/P ratio of 2.1, whereas steaming at higher temperatures resulted in decreased activities. Propylene was observed as the major olefin for both SSZ-39 and SAPO-18 in line with the cage-defining ring size of AEI. It was found through FT-IR and NH<sub>3</sub>-TPD that the increase in the steaming temperature decreases the Brønsted acidity of SSZ-39 which inhibits both the secondary hydrogenation of olefins to paraffins and the methanol-assisted hydrogen transfer reaction. Coupling of CO<sub>2</sub> to methanol (CTM) with methanol to olefins (MTO) reaction increased the CO<sub>2</sub> conversion and selectivity towards methanol equivalents by suppressing CO production in tandem systems as compared to the sole CTM reaction. The effect of catalyst bed configuration on product selectivity over the best performing catalyst was also studied, and the highest O/P ratio (3.7) was observed for a powder mixed system opposed to dual bed or mixed bed systems.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"289 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879900","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}
Photocatalytic water splitting on metal oxides often faces oxygen evolution inefficiency, reflecting the complex interplay of its two half-reactions. Strategies like heterojunctions, cocatalyst loading, or noble metal nanoparticles addition have been explored to address this. Using γ-Ga2O3 nanosheets as a model, we uncovered the formation of −O-O- species as the key barrier to stoichiometric splitting. To tackle this, a strategy was devised, Sr-doping to inhibit surface peroxidation. The resultant Sr-doped γ-Ga2O3 (Sr-Ga2O3) significantly improved activity and stability, achieving balanced H2 and O2 production under 125 W mercury lamp light. Upon further enhancement with Rh/Cr2O3 cocatalyst via photoreduction, the Sr-Ga2O3/(Rh/Cr2O3) composite demonstrated a remarkable 8.7 mmol·g−1·h−1 H2 and 4.4 mmol·g−1·h−1 O2 evolution rate, 8.3 times higher than γ-Ga2O3 alone, with a 34.1 % quantum efficiency under 260 nm light. This represents a record performance for Ga2O3-based photocatalytic water splitting. Mechanistically, Sr doping alters surface chemistry to favor direct oxygen release. Our study elucidates molecular-level insights into non-stoichiometric splitting mechanisms and offers a potent strategy to boost metal oxide photocatalysts’ water-splitting efficiency.
{"title":"Non-stoichiometric problem of photocatalytic water splitting on γ-Ga2O3: Cause and solution","authors":"Jinni Shen, Yuhua Zhong, Jianhan Lin, Haifeng Li, Chengwei Qiu, Xu Liu, Xun Wang, Rong Hu, Jinlin Long, Xuxu Wang, Zizhong Zhang","doi":"10.1016/j.jcat.2024.115929","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115929","url":null,"abstract":"Photocatalytic water splitting on metal oxides often faces oxygen evolution inefficiency, reflecting the complex interplay of its two half-reactions. Strategies like heterojunctions, cocatalyst loading, or noble metal nanoparticles addition have been explored to address this. Using γ-Ga<sub>2</sub>O<sub>3</sub> nanosheets as a model, we uncovered the formation of −O-O- species as the key barrier to stoichiometric splitting. To tackle this, a strategy was devised, Sr-doping to inhibit surface peroxidation. The resultant Sr-doped γ-Ga<sub>2</sub>O<sub>3</sub> (Sr-Ga<sub>2</sub>O<sub>3</sub>) significantly improved activity and stability, achieving balanced H<sub>2</sub> and O<sub>2</sub> production under 125 W mercury lamp light. Upon further enhancement with Rh/Cr<sub>2</sub>O<sub>3</sub> cocatalyst via photoreduction, the Sr-Ga<sub>2</sub>O<sub>3</sub>/(Rh/Cr<sub>2</sub>O<sub>3</sub>) composite demonstrated a remarkable 8.7 mmol·g<sup>−1</sup>·h<sup>−1</sup> H<sub>2</sub> and 4.4 mmol·g<sup>−1</sup>·h<sup>−1</sup> O<sub>2</sub> evolution rate, 8.3 times higher than γ-Ga<sub>2</sub>O<sub>3</sub> alone, with a 34.1 % quantum efficiency under 260 nm light. This represents a record performance for Ga<sub>2</sub>O<sub>3</sub>-based photocatalytic water splitting. Mechanistically, Sr doping alters surface chemistry to favor direct oxygen release. Our study elucidates molecular-level insights into non-stoichiometric splitting mechanisms and offers a potent strategy to boost metal oxide photocatalysts’ water-splitting efficiency.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"80 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884537","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 : 2024-12-22DOI: 10.1016/j.jcat.2024.115921
Yuhan Lin, , Quan Lin, Chongyang Wei, Yue Wang, Shouying Huang, Xing Chen, Xinbin Ma
Due to the development of material synthesis and characterization technology, as well as limited computational resources, the understanding of CO activation on Fe-based Fischer − Tropsch synthesis (FTS) catalysts is still changing, making catalyst screening and rational design difficult. In this work, we propose a novel model that bridges the structure of common iron carbides (including o-Fe7C3, χ-Fe5C2, θ-Fe3C, η-Fe2C and ε-Fe2.2C) with their CO activation capability. Using spin-polarized density functional theory (DFT), we explored CO activation pathways on a series of defective o-Fe7C3 surfaces. Advanced machine learning (ML) algorithms suitable for small datasets were employed to construct descriptor formulism with high predictive power for CO dissociation barriers. The ML-derived descriptor formulism unifies the catalytic expressions of various iron carbide phases, emphasizing the crucial roles of work function, carbon-vacancy formation energy, CO adsorption energy, coordination number, and the size of reaction sites in the CO dissociation process. This approach provides a deeper understanding of catalytic performance of distinct iron carbide surfaces and is applicable for designing high-performance catalysts for Fischer − Tropsch synthesis (FTS), thereby accelerating catalyst development. Furthermore, the strategy for identifying descriptors with a limited dataset highlights the potential of combining DFT and ML methods.
{"title":"Machine learning descriptors for CO activation on iron-based fischer − Tropsch catalyst","authors":"Yuhan Lin, , Quan Lin, Chongyang Wei, Yue Wang, Shouying Huang, Xing Chen, Xinbin Ma","doi":"10.1016/j.jcat.2024.115921","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115921","url":null,"abstract":"Due to the development of material synthesis and characterization technology, as well as limited computational resources, the understanding of CO activation on Fe-based Fischer − Tropsch synthesis (FTS) catalysts is still changing, making catalyst screening and rational design difficult. In this work, we propose a novel model that bridges the structure of common iron carbides (including o-Fe<sub>7</sub>C<sub>3</sub>, χ-Fe<sub>5</sub>C<sub>2</sub>, θ-Fe<sub>3</sub>C, η-Fe<sub>2</sub>C and ε-Fe<sub>2.2</sub>C) with their CO activation capability. Using spin-polarized density functional theory (DFT), we explored CO activation pathways on a series of defective o-Fe<sub>7</sub>C<sub>3</sub> surfaces. Advanced machine learning (ML) algorithms suitable for small datasets were employed to construct descriptor formulism with high predictive power for CO dissociation barriers. The ML-derived descriptor formulism unifies the catalytic expressions of various iron carbide phases, emphasizing the crucial roles of work function, carbon-vacancy formation energy, CO adsorption energy, coordination number, and the size of reaction sites in the CO dissociation process. This approach provides a deeper understanding of catalytic performance of distinct iron carbide surfaces and is applicable for designing high-performance catalysts for Fischer − Tropsch synthesis (FTS), thereby accelerating catalyst development. Furthermore, the strategy for identifying descriptors with a limited dataset highlights the potential of combining DFT and ML methods.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"64 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142870082","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 : 2024-12-22DOI: 10.1016/j.jcat.2024.115918
Fujun Ren, Jianian Cheng, Junqi Tian, Xiaojing Wu, Ruihui Zhang, Xingxing Zhou, Zelong Li, Can Li
The urgent need to replace the toxic mercuric chloride (HgCl2/AC) catalyst used in current industry for the production of vinyl chloride monomer (VCM) through acetylene hydrochlorination has been a great challenge. Although Au catalyst has been regarded as a potential catalyst for the reaction, it is unstable under reaction conditions. In this work, we report that atomically dispersed Au+ atoms supported on nitrogen doped carbon (Au/NC) can show high performance in the production of vinyl chloride monomer. This catalyst achieves an C2H2 conversion of 94.2 % and a VCM selectivity of 99.9 %, superior to Au catalyst supported on active carbon (Au/AC) without nitrogen doping. These active centers were identified to be the Au+ active centers, and the enhanced performance of the Au/NC catalyst is attributed to the presence of pyrrole nitrogen species, which strongly coordinate to the Au+ active centers promoting the adsorption and activation of C2H2. This research offers a promising way to stabilize the Au+ active centers and enhances the catalytic performance.
{"title":"Acetylene hydrochlorination to vinyl chloride monomer on Au(I) centers stabilized by pyrrole N in active carbon","authors":"Fujun Ren, Jianian Cheng, Junqi Tian, Xiaojing Wu, Ruihui Zhang, Xingxing Zhou, Zelong Li, Can Li","doi":"10.1016/j.jcat.2024.115918","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115918","url":null,"abstract":"The urgent need to replace the toxic mercuric chloride (HgCl<sub>2</sub>/AC) catalyst used in current industry for the production of vinyl chloride monomer (VCM) through acetylene hydrochlorination has been a great challenge. Although Au catalyst has been regarded as a potential catalyst for the reaction, it is unstable under reaction conditions. In this work, we report that atomically dispersed Au<sup>+</sup> atoms supported on nitrogen doped carbon (Au/NC) can show high performance in the production of vinyl chloride monomer. This catalyst achieves an C<sub>2</sub>H<sub>2</sub> conversion of 94.2 % and a VCM selectivity of 99.9 %, superior to Au catalyst supported on active carbon (Au/AC) without nitrogen doping. These active centers were identified to be the Au<sup>+</sup> active centers, and the enhanced performance of the Au/NC catalyst is attributed to the presence of pyrrole nitrogen species, which strongly coordinate to the Au<sup>+</sup> active centers promoting the adsorption and activation of C<sub>2</sub>H<sub>2</sub>. This research offers a promising way to stabilize the Au<sup>+</sup> active centers and enhances the catalytic performance.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"53 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874694","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 : 2024-12-22DOI: 10.1016/j.jcat.2024.115926
Tiantong Zhang, Yao Nian, Bao Wang, Jinli Zhang, William A. Goddard Ⅲ, You Han
Reserve–rich Cu–based catalysts are attractive for their favorable cost and sustainability and have exhibited extensive catalytic activities in the conversion of acetylene. However, the variable–valence and the presence of multi–species as well as the complexity of catalytic system pose challenges in deciphering the evolution process of Cu active center during working life–time. Herein, we investigated the evolution process of multivalent Cu–based species (Cu2+, Cu+ and Cu0) as model active centers for acetylene hydrochlorination. The reduction of Cu2+ driven by the activated carbon support and acetylene as well as oxidation of Cu0 induced by hydrogen chloride, have been clarified for these species, both of which with the terminated Cu+ species identified as the stable catalytic active center. Theoretical calculations have revealed the thermodynamics underlying the mechanism of species evolution determined by the covalent bond transition within Cu species, with comparisons of the differences in catalytic kinetics between sites. Moreover, a specific pathway for the catalytic decomposition of acetylene into coke deposits by Cu+ species was proposed. This knowledge provides mechanistic insights into the evolution process of Cu active centers in acetylene hydrochlorination, paving the way for understanding catalytic behavior and accurate catalyst design for new improved Cu–catalyzed ethynylation reactions.
{"title":"Mechanistic insights into the evolution of Cu active center in acetylene hydrochlorination","authors":"Tiantong Zhang, Yao Nian, Bao Wang, Jinli Zhang, William A. Goddard Ⅲ, You Han","doi":"10.1016/j.jcat.2024.115926","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115926","url":null,"abstract":"Reserve–rich Cu–based catalysts are attractive for their favorable cost and sustainability and have exhibited extensive catalytic activities in the conversion of acetylene. However, the variable–valence and the presence of multi–species as well as the complexity of catalytic system pose challenges in deciphering the evolution process of Cu active center during working life–time. Herein, we investigated the evolution process of multivalent Cu–based species (Cu<sup>2+</sup>, Cu<sup>+</sup> and Cu<sup>0</sup>) as model active centers for acetylene hydrochlorination. The reduction of Cu<sup>2+</sup> driven by the activated carbon support and acetylene as well as oxidation of Cu<sup>0</sup> induced by hydrogen chloride, have been clarified for these species, both of which with the terminated Cu<sup>+</sup> species identified as the stable catalytic active center. Theoretical calculations have revealed the thermodynamics underlying the mechanism of species evolution determined by the covalent bond transition within Cu species, with comparisons of the differences in catalytic kinetics between sites. Moreover, a specific pathway for the catalytic decomposition of acetylene into coke deposits by Cu<sup>+</sup> species was proposed. This knowledge provides mechanistic insights into the evolution process of Cu active centers in acetylene hydrochlorination, paving the way for understanding catalytic behavior and accurate catalyst design for new improved Cu–catalyzed ethynylation reactions.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"422 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874696","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 : 2024-12-22DOI: 10.1016/j.jcat.2024.115920
Ting He, Yuwei Lu, Shihao Han, Jingbin Hu, Pan Gao, Feng Xiao, Shaoxia Yang
Transition metal single atom catalysts (SACs) for boosting peroxymonosulfate (PMS) activation involving complex catalytic mechanism and multiple reaction pathways have received much attention, but regulating the reaction pathway of SACs is still an important challenge in the PMS-mediated Fenton-like reaction. Herein, a boron-doped Fe SAC with FeN3B configurations (Fe-BNC) was synthesized and selectively generated a non-radical pathway, in which the high-valent iron-oxo species (FeIVO) was determined as the main reactive oxygen species (ROS) by PMS activation. The FeBNC/PMS system not only exhibited remarkable reaction kinetic constant (0.949 min−1) and turnover frequency (9.49 L min−1g−1) for the phenol degradation, but also showed excellent selectivity to phenols with strong electron-donating ability. Mechanism exploration based on theoretical calculations revealed that high activity of FeBNC originated from the reinforced adsorption energy and enhanced overlap between Fe 3d and O 2p orbits, which facilitated to strengthen the FeO bonding and accelerate the electron transfer, thus modulating the PMS activation via a non-radical pathway. Successful extendibility of FeBNC in treatment of the real water and coking wastewater demonstrates its application potential. This work elucidates the mechanism of selectively generating a non-radical pathway over B-doped Fe-based SAC, and provides a rational strategy for preparing SACs alone with a non-radical pathway.
过渡金属单原子催化剂（SAC）用于促进过一硫酸盐（PMS）活化，涉及复杂的催化机理和多种反应途径，已受到广泛关注，但调节SAC的反应途径仍是PMS介导的类芬顿反应中的一个重要挑战。本文合成了一种具有 FeN3B 构型的掺硼铁 SAC（Fe-BNC），并选择性地产生了一种非自由基途径，其中高价铁氧物种（FeIVO）被确定为 PMS 活化的主要活性氧物种（ROS）。FeBNC/PMS 系统不仅在苯酚降解方面表现出显著的反应动力学常数（0.949 min-1）和周转频率（9.49 L min-1g-1），而且对电子供能能力强的苯酚表现出极佳的选择性。基于理论计算的机理探索表明，FeBNC 的高活性源于吸附能的增强和 Fe 3d 与 O 2p 轨道重叠的增强，这有利于加强 FeO 键合和加速电子转移，从而通过非自由基途径调节 PMS 的活化。FeBNC 在实际水和焦化废水处理中的成功推广证明了其应用潜力。这项研究阐明了掺杂 B 的铁基 SAC 选择性产生非辐射途径的机理，并为制备单独具有非辐射途径的 SAC 提供了合理的策略。
{"title":"Tuning the electron structure of single-atom Fe catalyst for designed peroxymonosulfate activation and phenols degradation","authors":"Ting He, Yuwei Lu, Shihao Han, Jingbin Hu, Pan Gao, Feng Xiao, Shaoxia Yang","doi":"10.1016/j.jcat.2024.115920","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115920","url":null,"abstract":"Transition metal single atom catalysts (SACs) for boosting peroxymonosulfate (PMS) activation involving complex catalytic mechanism and multiple reaction pathways have received much attention, but regulating the reaction pathway of SACs is still an important challenge in the PMS-mediated Fenton-like reaction. Herein, a boron-doped Fe SAC with FeN<sub>3</sub>B configurations (Fe-BNC) was synthesized and selectively generated a non-radical pathway, in which the high-valent iron-oxo species (Fe<sup>IV</sup><img alt=\"double bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/dbnd.gif\" style=\"vertical-align:middle\"/>O) was determined as the main reactive oxygen species (ROS) by PMS activation. The Fe<img alt=\"single bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif\" style=\"vertical-align:middle\"/>BNC/PMS system not only exhibited remarkable reaction kinetic constant (0.949 min<sup>−1</sup>) and turnover frequency (9.49 L min<sup>−1</sup>g<sup>−1</sup>) for the phenol degradation, but also showed excellent selectivity to phenols with strong electron-donating ability. Mechanism exploration based on theoretical calculations revealed that high activity of Fe<img alt=\"single bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif\" style=\"vertical-align:middle\"/>BNC originated from the reinforced adsorption energy and enhanced overlap between Fe 3d and O 2p orbits, which facilitated to strengthen the Fe<img alt=\"single bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif\" style=\"vertical-align:middle\"/>O bonding and accelerate the electron transfer, thus modulating the PMS activation via a non-radical pathway. Successful extendibility of Fe<img alt=\"single bond\" src=\"https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif\" style=\"vertical-align:middle\"/>BNC in treatment of the real water and coking wastewater demonstrates its application potential. This work elucidates the mechanism of selectively generating a non-radical pathway over B-doped Fe-based SAC, and provides a rational strategy for preparing SACs alone with a non-radical pathway.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"1 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142870083","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 : 2024-12-22DOI: 10.1016/j.jcat.2024.115917
Eric D. Hernandez, Dipti Bhave, Friederike C. Jentoft
Notwithstanding the relevance of zeolite-catalyzed hydrocarbon reactions, the materials properties that promote hydride transfer remain debated. Hydride transfer sustains the catalytic cycle in carbocation mechanisms, but, if uncontrolled, can lead to coke formation and catalyst deactivation. The objective of this work is to identify a correlation between hydride transfer activity and the nature of surface sites. The temperature-programmed conversion of 1-butanol on HZSM-5 serves as a test reaction, and semi-quantitative analysis of unsaturated surface products by UV–vis spectroscopy is combined with gas-phase product analysis by MS and GC to track hydride transfer activity. A series of MFI samples with various silicon-to-aluminum ratios, including two samples with different extra-framework aluminum content but otherwise equivalent, provide a range of Brønsted and Lewis acid site concentrations, as determined by pyridine adsorption and quantitative IR spectroscopy. Conversion of 1-butanol on HZSM-5 with a high aluminum content leads to the production of gas-phase alkanes (mainly isobutane) with concomitant formation of adsorbed alkylcyclopentenyl cations through a hydride transfer-mediated mechanism. HZSM-5 with low aluminum content is distinguished by butenes as the main volatile products. The cumulative amount of butanes formed exhibits an increasing trend with increasing acid site density, with distinction of the contributions of Brønsted or Lewis sites prevented by significant scatter. The maximum amount of surface alkylcyclopentenyl cations formed, detected at temperatures between 200 and 300 °C, is found to increase monotonically with the Brønsted acid site concentration, while not being correlated with the Lewis acid site concentration. The results demonstrate that hydride transfer activity can be tracked spectroscopically and that surface deposit formation is directly controlled by the zeolite Brønsted acid site concentration.
{"title":"Spectroscopic summation of surface species as a measure of zeolite hydride transfer activity","authors":"Eric D. Hernandez, Dipti Bhave, Friederike C. Jentoft","doi":"10.1016/j.jcat.2024.115917","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115917","url":null,"abstract":"Notwithstanding the relevance of zeolite-catalyzed hydrocarbon reactions, the materials properties that promote hydride transfer remain debated. Hydride transfer sustains the catalytic cycle in carbocation mechanisms, but, if uncontrolled, can lead to coke formation and catalyst deactivation. The objective of this work is to identify a correlation between hydride transfer activity and the nature of surface sites. The temperature-programmed conversion of 1-butanol on HZSM-5 serves as a test reaction, and semi-quantitative analysis of unsaturated surface products by UV–vis spectroscopy is combined with gas-phase product analysis by MS and GC to track hydride transfer activity. A series of MFI samples with various silicon-to-aluminum ratios, including two samples with different extra-framework aluminum content but otherwise equivalent, provide a range of Brønsted and Lewis acid site concentrations, as determined by pyridine adsorption and quantitative IR spectroscopy. Conversion of 1-butanol on HZSM-5 with a high aluminum content leads to the production of gas-phase alkanes (mainly isobutane) with concomitant formation of adsorbed alkylcyclopentenyl cations through a hydride transfer-mediated mechanism. HZSM-5 with low aluminum content is distinguished by butenes as the main volatile products. The cumulative amount of butanes formed exhibits an increasing trend with increasing acid site density, with distinction of the contributions of Brønsted or Lewis sites prevented by significant scatter. The maximum amount of surface alkylcyclopentenyl cations formed, detected at temperatures between 200 and 300 °C, is found to increase monotonically with the Brønsted acid site concentration, while not being correlated with the Lewis acid site concentration. The results demonstrate that hydride transfer activity can be tracked spectroscopically and that surface deposit formation is directly controlled by the zeolite Brønsted acid site concentration.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"41 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142869973","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}
O) was determined as the main reactive oxygen species (ROS) by PMS activation. The Fe
BNC/PMS system not only exhibited remarkable reaction kinetic constant (0.949 min−1) and turnover frequency (9.49 L min−1g−1) for the phenol degradation, but also showed excellent selectivity to phenols with strong electron-donating ability. Mechanism exploration based on theoretical calculations revealed that high activity of Fe
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