Xian Meng , Jian Liu , Zujian Tang , Bingxu Xi , Pu Yan , Xingran Wang , Kecheng Cao , Bo Yang , Xiaofei Guan
Ammonia (NH3) is one of the most important synthetic inorganic commodities. The current industrial NH3 production is dominated by the Haber–Bosch process with high energy cost and CO2 emission as well as the need for large-scale centralized operation. Liquid metals and molten salts have recently emerged as promising catalytic materials for NH3 synthesis. Herein, we present a molten system comprising Li–Zn alloy and eutectic LiCl–KCl salt for effective NH3 synthesis at 400 °C and 1 bar. The 70 mol% Li–Zn liquid alloy activates N2 dissociation more easily than the pure liquid Zn and the 60 mol% Li–Sn liquid alloy. Effective N2 fixation by the liquid Li–Zn alloy is followed by the hydrogenation of Li3N dissolved in the molten salt above. For the first time, this work reports a volcano-type relationship between the Li3N concentration in the molten salt and the NH3 synthesis rate when feeding H2 to the molten salt. Ab initio molecular dynamics simulations suggest that, within this system, both N2 cleavage and Li3N hydrogenation are quite reactive. Through combined experiments and simulations, this work unravels the molecular mechanisms of nitrogen fixation and ammonia synthesis in the liquid alloy–salt catalytic system, and also demonstrates effective strategies for improving the ammonia synthesis rate. Such a hybrid molten catalytic system offers a promising solution for distributed NH3 production with low energy cost and CO2 emission.
{"title":"Molten multi-phase catalytic system comprising Li–Zn alloy and LiCl–KCl salt for nitrogen fixation and ammonia synthesis at ambient pressure†","authors":"Xian Meng , Jian Liu , Zujian Tang , Bingxu Xi , Pu Yan , Xingran Wang , Kecheng Cao , Bo Yang , Xiaofei Guan","doi":"10.1039/d4cy00202d","DOIUrl":"10.1039/d4cy00202d","url":null,"abstract":"<div><p>Ammonia (NH<sub>3</sub>) is one of the most important synthetic inorganic commodities. The current industrial NH<sub>3</sub> production is dominated by the Haber–Bosch process with high energy cost and CO<sub>2</sub> emission as well as the need for large-scale centralized operation. Liquid metals and molten salts have recently emerged as promising catalytic materials for NH<sub>3</sub> synthesis. Herein, we present a molten system comprising Li–Zn alloy and eutectic LiCl–KCl salt for effective NH<sub>3</sub> synthesis at 400 °C and 1 bar. The 70 mol% Li–Zn liquid alloy activates N<sub>2</sub> dissociation more easily than the pure liquid Zn and the 60 mol% Li–Sn liquid alloy. Effective N<sub>2</sub> fixation by the liquid Li–Zn alloy is followed by the hydrogenation of Li<sub>3</sub>N dissolved in the molten salt above. For the first time, this work reports a volcano-type relationship between the Li<sub>3</sub>N concentration in the molten salt and the NH<sub>3</sub> synthesis rate when feeding H<sub>2</sub> to the molten salt. <em>Ab initio</em> molecular dynamics simulations suggest that, within this system, both N<sub>2</sub> cleavage and Li<sub>3</sub>N hydrogenation are quite reactive. Through combined experiments and simulations, this work unravels the molecular mechanisms of nitrogen fixation and ammonia synthesis in the liquid alloy–salt catalytic system, and also demonstrates effective strategies for improving the ammonia synthesis rate. Such a hybrid molten catalytic system offers a promising solution for distributed NH<sub>3</sub> production with low energy cost and CO<sub>2</sub> emission.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140596160","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}
H2O2 is a green oxidant, which is widely used in chemical production, environmental remediation, sustainable energy conversion and the medical industry. The traditional anthraquinone method for producing H2O2 is facing issues, such as potential safety hazards and environmental pollution. Therefore, green and sustainable production of H2O2 is desirably investigated. Solar-driven photocatalytic synthesis of H2O2 is a promising method, which requires no additional energy input and will not produce new pollution. g-C3N4 is a kind of nonmetallic photocatalyst, which has the advantages of low cost, environmental friendliness and high stability. However, g-C3N4 still faces the problems of a narrow visible light response range, low photo-generated electron/hole separation efficiency and short carrier lifetime. The polymer properties of g-C3N4 are conducive to introducing foreign atoms into the main body of the tri-s-triazine structure. The electronic structure and optical properties of g-C3N4 can be adjusted by doping, which can significantly improve the photocatalytic performance of g-C3N4. In this work, phosphorus doped g-C3N4 (P/g-C3N4) is prepared by a simple chemical vapor deposition method. The doping process also introduced defects in the bulk phase of g-C3N4, which overcomes drawbacks such as weak visible light capturing ability, low charge separation and transfer efficiency, and a slow mass transfer rate. In addition, the optimized conduction band position further enhances the reduction ability of photo-generated electrons, making its photocatalytic performance magnify by one order of magnitude compared to that of pure g-C3N4. Driven by visible light, P/g-C3N4 produces H2O2 through the photocatalytic oxygen reduction reaction (ORR) in 2 h, reaching a high concentration of 1460.22 μM, and it also maintains good catalytic repeatability in three-cycle catalytic experiments. P/g-C3N4 achieves the goal of efficient, stable and green synthesis of H2O2.
{"title":"Visible light photocatalytic synthesis of H2O2 on synergistic phosphorus-doped and defect engineered graphite C3N4†","authors":"Xiankui Xu , Zhonghai Zhang","doi":"10.1039/d4cy00455h","DOIUrl":"10.1039/d4cy00455h","url":null,"abstract":"<div><p>H<sub>2</sub>O<sub>2</sub> is a green oxidant, which is widely used in chemical production, environmental remediation, sustainable energy conversion and the medical industry. The traditional anthraquinone method for producing H<sub>2</sub>O<sub>2</sub> is facing issues, such as potential safety hazards and environmental pollution. Therefore, green and sustainable production of H<sub>2</sub>O<sub>2</sub> is desirably investigated. Solar-driven photocatalytic synthesis of H<sub>2</sub>O<sub>2</sub> is a promising method, which requires no additional energy input and will not produce new pollution. g-C<sub>3</sub>N<sub>4</sub> is a kind of nonmetallic photocatalyst, which has the advantages of low cost, environmental friendliness and high stability. However, g-C<sub>3</sub>N<sub>4</sub> still faces the problems of a narrow visible light response range, low photo-generated electron/hole separation efficiency and short carrier lifetime. The polymer properties of g-C<sub>3</sub>N<sub>4</sub> are conducive to introducing foreign atoms into the main body of the tri-<em>s</em>-triazine structure. The electronic structure and optical properties of g-C<sub>3</sub>N<sub>4</sub> can be adjusted by doping, which can significantly improve the photocatalytic performance of g-C<sub>3</sub>N<sub>4</sub>. In this work, phosphorus doped g-C<sub>3</sub>N<sub>4</sub> (P/g-C<sub>3</sub>N<sub>4</sub>) is prepared by a simple chemical vapor deposition method. The doping process also introduced defects in the bulk phase of g-C<sub>3</sub>N<sub>4</sub>, which overcomes drawbacks such as weak visible light capturing ability, low charge separation and transfer efficiency, and a slow mass transfer rate. In addition, the optimized conduction band position further enhances the reduction ability of photo-generated electrons, making its photocatalytic performance magnify by one order of magnitude compared to that of pure g-C<sub>3</sub>N<sub>4</sub>. Driven by visible light, P/g-C<sub>3</sub>N<sub>4</sub> produces H<sub>2</sub>O<sub>2</sub> through the photocatalytic oxygen reduction reaction (ORR) in 2 h, reaching a high concentration of 1460.22 μM, and it also maintains good catalytic repeatability in three-cycle catalytic experiments. P/g-C<sub>3</sub>N<sub>4</sub> achieves the goal of efficient, stable and green synthesis of H<sub>2</sub>O<sub>2</sub>.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141064182","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}
Martin Becker , Isabel Nowak , Katharina Hildebrand , Stephan Lütz , Katrin Rosenthal
The interest in multi-enzyme cascades for the synthesis of pharmaceutically relevant active ingredients has increased in recent years. Through a smart selection of enzymes, cascades enable multi-step synthesis in a one-pot reaction without the purification of intermediates. In this study, a five-enzyme cascade for the formation of cyclic 2′3′-GMP-AMP (2′3′-cGAMP) from adenosine and guanosine in seven reaction steps was successfully developed. First, the substrate scope of kinases for the phosphorylation of nucleosides and nucleotides was investigated, which were then combined in an enzyme cascade for 2′3′-cGAMP formation from adenosine, guanosine, and polyphosphate. An overall conversion of 57% of the substrates into 2′3′-cGAMP was achieved in relation to the initial guanosine concentration.
{"title":"Development of a multi-enzyme cascade for 2′3′-cGAMP synthesis from nucleosides†","authors":"Martin Becker , Isabel Nowak , Katharina Hildebrand , Stephan Lütz , Katrin Rosenthal","doi":"10.1039/d4cy00147h","DOIUrl":"10.1039/d4cy00147h","url":null,"abstract":"<div><p>The interest in multi-enzyme cascades for the synthesis of pharmaceutically relevant active ingredients has increased in recent years. Through a smart selection of enzymes, cascades enable multi-step synthesis in a one-pot reaction without the purification of intermediates. In this study, a five-enzyme cascade for the formation of cyclic 2′3′-GMP-AMP (2′3′-cGAMP) from adenosine and guanosine in seven reaction steps was successfully developed. First, the substrate scope of kinases for the phosphorylation of nucleosides and nucleotides was investigated, which were then combined in an enzyme cascade for 2′3′-cGAMP formation from adenosine, guanosine, and polyphosphate. An overall conversion of 57% of the substrates into 2′3′-cGAMP was achieved in relation to the initial guanosine concentration.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140834848","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}
There are few reports on the direct epoxidation of propylene catalyzed by LaCoO3 perovskite to form propylene oxide (PO) (both experimental and theoretical studies), especially the promoting effect of Cu doping. Herein, we report a comprehensive mechanistic study using both DFT calculations and microkinetic simulations for undoped and Cu-doped LaCoO3(110)–Cl to explore the effects of Cu doping in LaCoO3 perovskite towards PO selectivity. The propylene oxidation process consists of two parallel pathways, i.e., allylic hydrogen stripping and propylene oxametalcycle (OOMMP) intermediate mechanisms. Our results indicated that doping Cu has little effect on the selectivity for PO on LaCoO3 without Cl due to its very low reactivity. Alternatively, in the presence of Cl, copper doping not only lowers the strength of the Brønsted base of molecular , and thus disfavors the propylene α-H striping process, leading to higher OOMMP intermediate formation selectivity, but also enhances the secondary chemistry, improving both the selectivity and activity for PO formation. Moreover, the microkinetic modelling results showed that the Cu-doped LaO-terminated LaCoO3(110)–Cl surface has higher selectivity for PO than that of the Cu-doped CoO-terminated LaCoO3(110)–Cl surface. It is hoped that the present work will help researchers better understand the mechanism of Cu doping in LaCoO3-like perovskite catalysts for PO formation reactions.
关于 LaCoO3 包晶催化丙烯直接环氧化生成环氧丙烷(PO)的研究(包括实验和理论研究),尤其是关于掺杂铜的促进作用的报道很少。在此,我们利用 DFT 计算和微动力学模拟对未掺杂和掺杂 Cu 的 LaCoO3(110)-Cl 进行了全面的机理研究,以探讨在 LaCoO3 包晶中掺杂 Cu 对氧化丙烯选择性的影响。丙烯氧化过程包括两个平行的途径,即烯丙基氢剥离和丙烯氧金属环(OOMMP)中间机制。我们的研究结果表明,在没有 Cl 的情况下,掺入 Cu 对 LaCoO3 上的 PO 选择性影响很小,因为其反应活性很低。相反,在有 Cl 的情况下,掺铜不仅会降低分子Ⅴ的布氏碱强度,从而不利于丙烯的 α-H 剥离过程,导致更高的 OOMMP 中间体形成选择性,而且还会增强二次化学反应,提高形成 PO 的选择性和活性。此外,微动力学建模结果表明,掺铜的 LaO 端面 LaCoO3(110)-Cl 表面对 PO 的选择性高于掺铜的 CoO 端面 LaCoO3(110)-Cl 表面。希望本研究能帮助研究人员更好地理解在类 LaCoO3 包晶催化剂中掺杂铜以促进 PO 生成反应的机理。
{"title":"Copper-doped LaCoO3 for direct propylene epoxidation: a DFT study†","authors":"Wen-Jing Wang , Gui-Chang Wang","doi":"10.1039/d4cy00140k","DOIUrl":"10.1039/d4cy00140k","url":null,"abstract":"<div><p>There are few reports on the direct epoxidation of propylene catalyzed by LaCoO<sub>3</sub> perovskite to form propylene oxide (PO) (both experimental and theoretical studies), especially the promoting effect of Cu doping. Herein, we report a comprehensive mechanistic study using both DFT calculations and microkinetic simulations for undoped and Cu-doped LaCoO<sub>3</sub>(110)–Cl to explore the effects of Cu doping in LaCoO<sub>3</sub> perovskite towards PO selectivity. The propylene oxidation process consists of two parallel pathways, <em>i.e.</em>, allylic hydrogen stripping and propylene oxametalcycle (OOMMP) intermediate mechanisms. Our results indicated that doping Cu has little effect on the selectivity for PO on LaCoO<sub>3</sub> without Cl due to its very low reactivity. Alternatively, in the presence of Cl, copper doping not only lowers the strength of the Brønsted base of molecular <figure><img></figure>, and thus disfavors the propylene α-H striping process, leading to higher OOMMP intermediate formation selectivity, but also enhances the secondary chemistry, improving both the selectivity and activity for PO formation. Moreover, the microkinetic modelling results showed that the Cu-doped LaO-terminated LaCoO<sub>3</sub>(110)–Cl surface has higher selectivity for PO than that of the Cu-doped CoO-terminated LaCoO<sub>3</sub>(110)–Cl surface. It is hoped that the present work will help researchers better understand the mechanism of Cu doping in LaCoO<sub>3</sub>-like perovskite catalysts for PO formation reactions.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148087","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}
Xu Yang , Wu Liu , Shuyi Su , Jinfeng Li , Xiaoyang Wang , Mengjie Lian , Lei Miao
In this study, we successfully synthesized a carbon-coated nickel phosphide composite catalyst (Ni2P@C) through a strategy of polyvinylpyrrolidone (PVP)-assisted pyrolysis and phosphidation of Ni-MOF. Thorough structural characterization revealed that the assistance of PVP significantly decreased the size of the nickel nanoparticles during pyrolysis, and the subsequent gas phosphidation transformed the metallic nickel into the Ni2P phase with strengthened Ni–P synergy. The resulting core–shell structured Ni2P@C possessed a substantial number of surface Niδ + sites with electron deficiency, which served as both a metal center to dissociate hydrogen and a Lewis acid to activate the C–O bond. Remarkably, under mild reaction conditions (120 °C and pH 2 of 2.0 MPa), the Ni2P@C composite demonstrated exceptional activity for hydrodeoxygenation of furfuryl alcohol, achieving an impressive 2-methylfuran productivity of 1.7 g2-MF gCata−1 h−1. These results surpass the performance of most non-noble metal catalysts currently reported. This study could provide valuable insights for the rational design of advanced carbon-coated Ni2P composite catalysts for hydrogenative biomass upgrading.
{"title":"Carbon-coated nickel phosphide with enriched surface Niδ + sites enables an exceptionally high productivity of 2-methylfuran from biomass upgrading†","authors":"Xu Yang , Wu Liu , Shuyi Su , Jinfeng Li , Xiaoyang Wang , Mengjie Lian , Lei Miao","doi":"10.1039/d3cy01609a","DOIUrl":"10.1039/d3cy01609a","url":null,"abstract":"<div><p>In this study, we successfully synthesized a carbon-coated nickel phosphide composite catalyst (Ni<sub>2</sub>P@C) through a strategy of polyvinylpyrrolidone (PVP)-assisted pyrolysis and phosphidation of Ni-MOF. Thorough structural characterization revealed that the assistance of PVP significantly decreased the size of the nickel nanoparticles during pyrolysis, and the subsequent gas phosphidation transformed the metallic nickel into the Ni<sub>2</sub>P phase with strengthened Ni–P synergy. The resulting core–shell structured Ni<sub>2</sub>P@C possessed a substantial number of surface Ni<sup>δ +</sup> sites with electron deficiency, which served as both a metal center to dissociate hydrogen and a Lewis acid to activate the C–O bond. Remarkably, under mild reaction conditions (120 °C and <em>p</em><sub>H 2</sub> of 2.0 MPa), the Ni<sub>2</sub>P@C composite demonstrated exceptional activity for hydrodeoxygenation of furfuryl alcohol, achieving an impressive 2-methylfuran productivity of 1.7 g<sub>2-MF</sub> g<sub>Cata</sub><sup>−1</sup> h<sup>−1</sup>. These results surpass the performance of most non-noble metal catalysts currently reported. This study could provide valuable insights for the rational design of advanced carbon-coated Ni<sub>2</sub>P composite catalysts for hydrogenative biomass upgrading.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140933609","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}
Bharathkumar H. J. , Bhavana R. Shivankar , Sailaja Krishnamurty , Dehong Chen , Rachel A. Caruso , Kothandam Krishnamoorthy
Sulfur undergoes various changes from solid S8 to soluble lithium polysulfides (Li2S8–Li2S4) and insoluble Li2S2 and Li2S during charge–discharge cycling of lithium sulfur (Li–S) batteries. The dissolution of sulfur-containing compounds in battery electrolytes and their movement between electrodes, known as the polysulfide shuttle effect, decreases the battery performance. In addition, the kinetics of sulfur redox reactions are sluggish. Different host materials have been explored to address these issues. Herein, nanofibres of conjugated polymers have been synthesised that have multiple electron transport pathways. The cross-linker is nickel phthalocyanine tetrasulfonic acid tetrasodium salt (NPTS). Sulfur is situated in the voids of cross-linked nanofibres of the polymer and Ni2+ present in NPTS attracts the negative charge-bearing polysulfides. Due to the confinement and polyvalent electrostatic attraction, the solubility of sulfur and polysulfide is suppressed. Density functional theory calculations revealed that S2− interacts with Ni2+ and Li+ interacts with the pyrrolic nitrogens of PPy-NPTS. The overlap of the p-orbitals of sulfur and nickel is determined from the density of states calculations. The bond length of Li2S is ideal for this interaction, hence this molecule showed the highest adsorption energy with the cross-linked polymeric host. The adsorption energy decreased upon an increase in the number of sulfur atoms in the polysulfide chain due to the bond length mismatch. However, due to electrostatic polyvalent interaction, the adsorption energy is sufficient to suppress polysulfide dissolution. Thus, the structure of this host material with nickel cations and pyrrolic nitrogens is suitable to adsorb lithium polysulfides irrespective of their length, unlike neutral hosts. This efficient binding also improved the electrocatalysis of the sulfur redox reaction. Hence, the Li–S battery containing these nanofibres showed a specific capacity of 1326 mA h g−1 at 0.2C. Batteries fabricated considering practical parameters, such as low electrolyte to sulfur ratio of 5.0 μL mg−1 with sulfur loading of 4.0 mg cm−2, showed impressive performance.
{"title":"Polyvalent interaction and confinement to suppress polysulfide dissolution and improve electrocatalysis†","authors":"Bharathkumar H. J. , Bhavana R. Shivankar , Sailaja Krishnamurty , Dehong Chen , Rachel A. Caruso , Kothandam Krishnamoorthy","doi":"10.1039/d4cy00243a","DOIUrl":"10.1039/d4cy00243a","url":null,"abstract":"<div><p>Sulfur undergoes various changes from solid S<sub>8</sub> to soluble lithium polysulfides (Li<sub>2</sub>S<sub>8</sub>–Li<sub>2</sub>S<sub>4</sub>) and insoluble Li<sub>2</sub>S<sub>2</sub> and Li<sub>2</sub>S during charge–discharge cycling of lithium sulfur (Li–S) batteries. The dissolution of sulfur-containing compounds in battery electrolytes and their movement between electrodes, known as the polysulfide shuttle effect, decreases the battery performance. In addition, the kinetics of sulfur redox reactions are sluggish. Different host materials have been explored to address these issues. Herein, nanofibres of conjugated polymers have been synthesised that have multiple electron transport pathways. The cross-linker is nickel phthalocyanine tetrasulfonic acid tetrasodium salt (NPTS). Sulfur is situated in the voids of cross-linked nanofibres of the polymer and Ni<sup>2+</sup> present in NPTS attracts the negative charge-bearing polysulfides. Due to the confinement and polyvalent electrostatic attraction, the solubility of sulfur and polysulfide is suppressed. Density functional theory calculations revealed that S<sup>2−</sup> interacts with Ni<sup>2+</sup> and Li<sup>+</sup> interacts with the pyrrolic nitrogens of PPy-NPTS. The overlap of the p-orbitals of sulfur and nickel is determined from the density of states calculations. The bond length of Li<sub>2</sub>S is ideal for this interaction, hence this molecule showed the highest adsorption energy with the cross-linked polymeric host. The adsorption energy decreased upon an increase in the number of sulfur atoms in the polysulfide chain due to the bond length mismatch. However, due to electrostatic polyvalent interaction, the adsorption energy is sufficient to suppress polysulfide dissolution. Thus, the structure of this host material with nickel cations and pyrrolic nitrogens is suitable to adsorb lithium polysulfides irrespective of their length, unlike neutral hosts. This efficient binding also improved the electrocatalysis of the sulfur redox reaction. Hence, the Li–S battery containing these nanofibres showed a specific capacity of 1326 mA h g<sup>−1</sup> at 0.2C. Batteries fabricated considering practical parameters, such as low electrolyte to sulfur ratio of 5.0 μL mg<sup>−1</sup> with sulfur loading of 4.0 mg cm<sup>−2</sup>, showed impressive performance.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148082","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}
Shuang Gao , Zhuo Wang , Ping Nie , Juan Jian , Hairui Wang , Fen Yao , Limin Chang
The development of non-precious metal overall water splitting electrocatalysts under high current density is of utmost importance in feasible water splitting technology. Herein, we present an ambient temperature sulfuration strategy through in situ construction of iron nickel sulfide nanosheets vertically on 3D microporous iron foam. The synthesis conditions are simple and conducive to large-scale production. The FeNiS/IF nanosheets exhibit outstanding performance towards the HER and OER at large current densities, even in the order of 1000 mA cm−2. Density functional theory calculations show that FeNiS/IF as a bimetallic sulfide exhibits superior HER activity in alkaline media due to the optimization of ΔGH* and a more favorable water adsorption process.
开发高电流密度下的非贵金属整体水分离电催化剂对于可行的水分离技术至关重要。在此,我们提出了一种通过在三维微孔铁泡沫上垂直原位构建硫化铁镍纳米片的常温硫化策略。合成条件简单,有利于大规模生产。FeNiS/IF 纳米片在大电流密度(甚至 1000 mA cm-2 量级)条件下表现出卓越的 HER 和 OER 性能。密度泛函理论计算表明,FeNiS/IF 作为一种双金属硫化物,由于优化了 ΔGH* 和更有利的水吸附过程,在碱性介质中表现出更高的 HER 活性。
{"title":"Construction of nickel iron sulfide at ambient temperature on Fe foam for high-current overall water splitting†","authors":"Shuang Gao , Zhuo Wang , Ping Nie , Juan Jian , Hairui Wang , Fen Yao , Limin Chang","doi":"10.1039/d4cy00328d","DOIUrl":"10.1039/d4cy00328d","url":null,"abstract":"<div><p>The development of non-precious metal overall water splitting electrocatalysts under high current density is of utmost importance in feasible water splitting technology. Herein, we present an ambient temperature sulfuration strategy through <em>in situ</em> construction of iron nickel sulfide nanosheets vertically on 3D microporous iron foam. The synthesis conditions are simple and conducive to large-scale production. The FeNiS/IF nanosheets exhibit outstanding performance towards the HER and OER at large current densities, even in the order of 1000 mA cm<sup>−2</sup>. Density functional theory calculations show that FeNiS/IF as a bimetallic sulfide exhibits superior HER activity in alkaline media due to the optimization of Δ<em>G</em><sub>H*</sub> and a more favorable water adsorption process.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141254749","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}
Here, we describe the direct exploitation of visible light energy by using a conjugated polymer network (CPN) that is susceptible to an in situ loading of Pd metal for photocatalytic Suzuki-type C–C cross-coupling reaction. The requisite products were quantitatively achieved (yield >90%), under photo-illumination using an environment-friendly solvent. Under normal solar light, similar catalytic activity was maintained using the same experimental conditions. To comprehend the function of every variable and reactive species involved in the reaction's path, in-depth mechanistic studies were carried out. It is further underlined that the CPN has greater catalytic efficiency based on its exceptional resistance to 50 substrates of varying functionality, for 5 consecutive catalyst recycling cycles as well as bulk-scale reactions and a turnover frequency value of up to 1840 h−1 at a low catalyst dose of Pd (0.0125 mol%), while maintaining its catalytic efficacy. Its catalytic competence in terms of scope, scalability, environmental friendliness, and sustainability supports its proficiency.
{"title":"In situ palladium-doped conjugated polymer network for visible light and natural sunlight-driven Suzuki type cross-coupling reaction at room temperature†","authors":"Raj Laxmi , Anshuman , Anamika , Neelam Gupta , Biplab K. Kuila","doi":"10.1039/d4cy00089g","DOIUrl":"10.1039/d4cy00089g","url":null,"abstract":"<div><p>Here, we describe the direct exploitation of visible light energy by using a conjugated polymer network (CPN) that is susceptible to an <em>in situ</em> loading of Pd metal for photocatalytic Suzuki-type C–C cross-coupling reaction. The requisite products were quantitatively achieved (yield >90%), under photo-illumination using an environment-friendly solvent. Under normal solar light, similar catalytic activity was maintained using the same experimental conditions. To comprehend the function of every variable and reactive species involved in the reaction's path, in-depth mechanistic studies were carried out. It is further underlined that the CPN has greater catalytic efficiency based on its exceptional resistance to 50 substrates of varying functionality, for 5 consecutive catalyst recycling cycles as well as bulk-scale reactions and a turnover frequency value of up to 1840 h<sup>−1</sup> at a low catalyst dose of Pd (0.0125 mol%), while maintaining its catalytic efficacy. Its catalytic competence in terms of scope, scalability, environmental friendliness, and sustainability supports its proficiency.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148068","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}
Heretofore selective hydrodeoxygenation (HDO) of syringol remained limited and challenging due to the complicated structure of syringol compared to other lignin-derived model compounds such as guaiacol and phenol. Here, we report an efficient HDO of syringol to cyclohexanol (CYHAOL) over a reduced graphene oxide (rGO)-supported Co catalyst (Co/rGO) capable of heterolytic dissociation of H2 molecules. A combination of characterization methods, including HAADF-STEM, XPS, XRD, etc., and experiments reveals that Co/rGO has a unique morphology composed of core–shell structured multivalent Co oxide nanoparticles (CoOx) incorporating oxygen vacancies distributed on the graphene surface, and high-density single Co atoms embedded in the graphene matrix, both of which can afford the highly active Hδ − species for the HDO reaction. The morphologies of the supported Co species are highly dependent on the graphene textures. The Co/rGO catalyst without pre-reduction treatment demonstrated exceptional catalytic activity in the HDO of syringol with high selectivity to CYHAOL under mild conditions and good stability in the catalyst components. The metal-oxide-based Co/rGO catalyst does not require the pre-reduction treatment, simplifying the catalyst preparation process and eliminating the severe sintering of the metal species.
与愈创木酚和苯酚等其他木质素衍生模型化合物相比,紫丁香醇的结构复杂,因此迄今为止紫丁香醇的选择性加氢脱氧(HDO)仍然具有局限性和挑战性。在此,我们报告了在还原氧化石墨烯(rGO)支撑的 Co 催化剂(Co/rGO)上将丁香酚高效 HDO 为环己醇(CYHAOL)的过程,该催化剂能够异解 H2 分子。结合 HAADF-STEM、XPS、XRD 等表征方法和实验发现,Co/rGO 具有独特的形态,由核-壳结构的多价氧化钴纳米颗粒(CoOx)和嵌入石墨烯基质中的高密度单 Co 原子组成,前者在石墨烯表面分布着氧空位,后者可为 HDO 反应提供高活性的 Hδ- 物种。支撑的 Co 原子的形态与石墨烯的质地密切相关。未经预还原处理的 Co/rGO 催化剂在丁香酚的 HDO 反应中表现出优异的催化活性,在温和条件下对 CYHAOL 具有高选择性,并且催化剂组分具有良好的稳定性。基于金属氧化物的 Co/rGO 催化剂无需进行预还原处理,从而简化了催化剂的制备过程,并避免了金属物种的严重烧结。
{"title":"Core–shell structured cobalt oxide nanoparticles and single Co atoms supported on graphene for selective hydrodeoxygenation of syringol to cyclohexanol†","authors":"Xiaohan Qu , Saibei Zhang , Jingbo Mao , Hui Lv , Jinxia Zhou","doi":"10.1039/d4cy00295d","DOIUrl":"10.1039/d4cy00295d","url":null,"abstract":"<div><p>Heretofore selective hydrodeoxygenation (HDO) of syringol remained limited and challenging due to the complicated structure of syringol compared to other lignin-derived model compounds such as guaiacol and phenol. Here, we report an efficient HDO of syringol to cyclohexanol (CYHAOL) over a reduced graphene oxide (rGO)-supported Co catalyst (Co/rGO) capable of heterolytic dissociation of H<sub>2</sub> molecules. A combination of characterization methods, including HAADF-STEM, XPS, XRD, <em>etc.</em>, and experiments reveals that Co/rGO has a unique morphology composed of core–shell structured multivalent Co oxide nanoparticles (CoO<sub>x</sub>) incorporating oxygen vacancies distributed on the graphene surface, and high-density single Co atoms embedded in the graphene matrix, both of which can afford the highly active H<sup>δ −</sup> species for the HDO reaction. The morphologies of the supported Co species are highly dependent on the graphene textures. The Co/rGO catalyst without pre-reduction treatment demonstrated exceptional catalytic activity in the HDO of syringol with high selectivity to CYHAOL under mild conditions and good stability in the catalyst components. The metal-oxide-based Co/rGO catalyst does not require the pre-reduction treatment, simplifying the catalyst preparation process and eliminating the severe sintering of the metal species.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059280","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}
Fang Wang , Yi Ouyang , Pengfei Zhou , Yan Zhang , Renjun Gao , Bekir Engin Eser , Zheng Guo
Herein, we designed a NIR (near-infrared)-responsive multifunctional nanoreactor that can be used for precise and immediate regulation of chemoenzymatic degradation of organophosphates (OPs). The thermophilic phosphotriesterases (PTEs) and gold nanoparticles (AuNPs) were encapsulated in the ZIF-8 structure yielding an Au/PTE/ZIF-8 nanocomposite, which can be modulated by NIR as a result of the photothermal effect of AuNPs. The Au/PTE/ZIF-8 nanoreactor demonstrated excellent performance in mediating cascade reactions from enzymatic hydrolysis of OPs (>90% conversion in 10 min) to the subsequent reduction of the resulting 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) by NaBH4 (>90% yield of 4-AP in 30 min). An immediate light-to-heat conversion when NIR was applied to Au/PTE/ZIF-8 at room temperature enables a 2-fold increase in the specific activity of phosphotriesterase from S. islandicus compared to thermo-heating at 70 °C. Based on the fact that there was a significant acceleration in 4-NP reduction by Au/PTE/ZIF-8, we proposed a plausible reaction mechanism (reaction pathway) suggesting that: 1) cooperative actions between Au, ZIF-8 and substrates take place by promoting polarization and cleavage of the B–H bond in NaBH4 for releasing hydride facilitating electron and hydride transfer to 4-NP; and 2) stabilizing the formation of intermediates or the transition state by coordination with a ZIF-8 delocalized network and/or Au.
{"title":"NIR-accelerated cascade reaction for degradation of organophosphorus compounds by Au/PTE/ZIF-8: cooperative effect and mechanism†","authors":"Fang Wang , Yi Ouyang , Pengfei Zhou , Yan Zhang , Renjun Gao , Bekir Engin Eser , Zheng Guo","doi":"10.1039/d4cy00311j","DOIUrl":"10.1039/d4cy00311j","url":null,"abstract":"<div><p>Herein, we designed a NIR (near-infrared)-responsive multifunctional nanoreactor that can be used for precise and immediate regulation of chemoenzymatic degradation of organophosphates (OPs). The thermophilic phosphotriesterases (PTEs) and gold nanoparticles (AuNPs) were encapsulated in the ZIF-8 structure yielding an Au/PTE/ZIF-8 nanocomposite, which can be modulated by NIR as a result of the photothermal effect of AuNPs. The Au/PTE/ZIF-8 nanoreactor demonstrated excellent performance in mediating cascade reactions from enzymatic hydrolysis of OPs (>90% conversion in 10 min) to the subsequent reduction of the resulting 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) by NaBH<sub>4</sub> (>90% yield of 4-AP in 30 min). An immediate light-to-heat conversion when NIR was applied to Au/PTE/ZIF-8 at room temperature enables a 2-fold increase in the specific activity of phosphotriesterase from <em>S. islandicus</em> compared to thermo-heating at 70 °C. Based on the fact that there was a significant acceleration in 4-NP reduction by Au/PTE/ZIF-8, we proposed a plausible reaction mechanism (reaction pathway) suggesting that: 1) cooperative actions between Au, ZIF-8 and substrates take place by promoting polarization and cleavage of the B–H bond in NaBH<sub>4</sub> for releasing hydride facilitating electron and hydride transfer to 4-NP; and 2) stabilizing the formation of intermediates or the transition state by coordination with a ZIF-8 delocalized network and/or Au.</p></div>","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148495","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}