Zinnia Arora, Meriem Rais, Vasile I Pârvulescu, Karine Philippot, Jérôme Durand, Maryse Gouygou
Supported chiral catalysts were prepared by ionic anchoring of two cationic rhodium complexes (A and B) onto functionalized carbon nanotubes (CNTs). The immobilization of the Rh complexes was done by applying two ionic anchoring strategies: i) electrostatic interaction with the negatively charged surface of carboxylate‐functionalized CNTs (CNT‐COO‐); ii) electrostatic interaction through a heteropoly acid (HPA) spacer previously grafted at the CNTs surface (CNT‐HPA). The characterization of the obtained CNT‐COO‐@complex A, CNT‐COO‐@complex B, CNT‐HPA@complex A, and CNT‐HPA@complex B materials by ICP, TEM and XPS showed the successful anchoring of the Rh complexes onto the supports. The HPA spacer was found to increase the catalyst’s stability and to limit the effect of the CNT surface on the catalytic performances of the immobilized Rh complexes. CNT‐HPA@complexes performed the hydrogenation of dimethyl itaconate into methyl succinate with high conversions (83‐100%) and good enantioselectivities (58‐63%). The recyclability tests showed the catalysts were less active but still enantioselective after recycling.
{"title":"Non‐covalent Immobilization of Chiral Rhodium Catalysts on Carbon Nanotubes for Asymmetric Hydrogenation","authors":"Zinnia Arora, Meriem Rais, Vasile I Pârvulescu, Karine Philippot, Jérôme Durand, Maryse Gouygou","doi":"10.1002/cnma.202400125","DOIUrl":"https://doi.org/10.1002/cnma.202400125","url":null,"abstract":"Supported chiral catalysts were prepared by ionic anchoring of two cationic rhodium complexes (A and B) onto functionalized carbon nanotubes (CNTs). The immobilization of the Rh complexes was done by applying two ionic anchoring strategies: i) electrostatic interaction with the negatively charged surface of carboxylate‐functionalized CNTs (CNT‐COO‐); ii) electrostatic interaction through a heteropoly acid (HPA) spacer previously grafted at the CNTs surface (CNT‐HPA). The characterization of the obtained CNT‐COO‐@complex A, CNT‐COO‐@complex B, CNT‐HPA@complex A, and CNT‐HPA@complex B materials by ICP, TEM and XPS showed the successful anchoring of the Rh complexes onto the supports. The HPA spacer was found to increase the catalyst’s stability and to limit the effect of the CNT surface on the catalytic performances of the immobilized Rh complexes. CNT‐HPA@complexes performed the hydrogenation of dimethyl itaconate into methyl succinate with high conversions (83‐100%) and good enantioselectivities (58‐63%). The recyclability tests showed the catalysts were less active but still enantioselective after recycling.","PeriodicalId":54339,"journal":{"name":"ChemNanoMat","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sergio Battiato, Mario Urso, Anna Lucia Pellegrino, Antonio Terrasi, Salvo Mirabella
Green hydrogen production by water splitting holds great potential as a clean and renewable source of energy for sustainable energy solutions. However, the efficiency of this process is hampered by the sluggish oxygen evolution reaction (OER). Overcoming these kinetic hurdles requires the development of highly efficient electrocatalysts. This study explores the effect of transition metal doping on the electrocatalytic properties of Ni(OH)2 microflowers towards alkaline OER. Transition metal-doped Ni(OH)2 microflowers, with highly porous structures due to interconnected nanosheets, are synthesized by a facile, cheap, and scalable chemical bath deposition (CBD), and combined with graphene paper (GP) substrates to fabricate electrodes. Through a systematic exploration of the relationship between the transition metal dopant element type (Mn, Fe, Co, Zn) or concentration and the consequent electrochemical properties, Co-doping demonstrates improvement in the overpotential at a current density of 10 mA cm−2 (329 mV), Tafel slope (45 mV dec−1), and other key performance indicators of Ni(OH)2 microflowers for OER. These results are attributed to the high number of active sites and their enhanced electrocatalytic activity benefiting from the presence of the transition metal dopant. The proposed strategy paves the way for the development of cost-effective and highly efficient electrocatalysts for water splitting technologies.
通过水分裂生产绿色氢气作为一种清洁的可再生能源,在可持续能源解决方案中具有巨大潜力。然而,氧气进化反应(OER)的迟缓阻碍了这一过程的效率。要克服这些动力学障碍,需要开发高效的电催化剂。本研究探讨了过渡金属掺杂对 Ni(OH)2 微流体碱性 OER 电催化特性的影响。掺杂过渡金属的镍(OH)2微流子因纳米片的相互连接而具有高多孔结构,该微流子是通过一种简便、廉价和可扩展的化学沉积(CBD)方法合成的,并与石墨烯纸(GP)基底结合制成电极。通过系统地探索过渡金属掺杂元素类型(锰、铁、钴、锌)或浓度与相应电化学特性之间的关系,掺杂钴改善了用于 OER 的 Ni(OH)2 微流体在 10 mA cm-2 电流密度下的过电位(329 mV)、塔菲尔斜率(45 mV dec-1)以及其他关键性能指标。这些结果归因于大量活性位点及其因过渡金属掺杂剂的存在而增强的电催化活性。所提出的策略为开发用于水分离技术的经济高效的电催化剂铺平了道路。
{"title":"Comparative Study on the Electrocatalytic Activity of Transition Metal-Doped Ni(OH)2 Microflowers for Oxygen Evolution Reaction","authors":"Sergio Battiato, Mario Urso, Anna Lucia Pellegrino, Antonio Terrasi, Salvo Mirabella","doi":"10.1002/cnma.202400137","DOIUrl":"https://doi.org/10.1002/cnma.202400137","url":null,"abstract":"<p>Green hydrogen production by water splitting holds great potential as a clean and renewable source of energy for sustainable energy solutions. However, the efficiency of this process is hampered by the sluggish oxygen evolution reaction (OER). Overcoming these kinetic hurdles requires the development of highly efficient electrocatalysts. This study explores the effect of transition metal doping on the electrocatalytic properties of Ni(OH)<sub>2</sub> microflowers towards alkaline OER. Transition metal-doped Ni(OH)<sub>2</sub> microflowers, with highly porous structures due to interconnected nanosheets, are synthesized by a facile, cheap, and scalable chemical bath deposition (CBD), and combined with graphene paper (GP) substrates to fabricate electrodes. Through a systematic exploration of the relationship between the transition metal dopant element type (Mn, Fe, Co, Zn) or concentration and the consequent electrochemical properties, Co-doping demonstrates improvement in the overpotential at a current density of 10 mA cm<sup>−2</sup> (329 mV), Tafel slope (45 mV dec<sup>−1</sup>), and other key performance indicators of Ni(OH)<sub>2</sub> microflowers for OER. These results are attributed to the high number of active sites and their enhanced electrocatalytic activity benefiting from the presence of the transition metal dopant. The proposed strategy paves the way for the development of cost-effective and highly efficient electrocatalysts for water splitting technologies.</p>","PeriodicalId":54339,"journal":{"name":"ChemNanoMat","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yoshiki Kiyota, Seiji Ono, Dr. Kaito Sasaki, Nanako Tamai, Hironori Sugimoto, Prof. Dr. Yosuke Okamura, Prof. Dr. Shinichi Koguchi, Prof. Dr. Masashi Higuchi, Prof. Dr. Yu Nagase, Prof. Dr. Naoki Shinyashiki, Prof. Dr. Sayaka Uchida, Prof. Dr. Takeru Ito
Highly conductive inorganic-organic hybrid crystals were constructed by using polyoxovanadate cluster and ionic-liquid cation. Two types of hybrid crystals containing alkaline earth metal (divalent) cations were obtained. Conductivities under a humidified condition reached 3.3×10–3 S cm–1 at 353 K (80 °C). More information can be found in the Research Article by Takeru Ito and co-workers.