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Selective reduction

About: Selective reduction is a(n) research topic. Over the lifetime, 1394 publication(s) have been published within this topic receiving 29090 citation(s). The topic is also known as: multifetal pregnancy reduction & Pregnancy Reduction, Multifetal.
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Journal ArticleDOI
TL;DR: Th thin films of nanosized metal-organic frameworks (MOFs) are introduced as atomically defined and nanoscopic materials that function as catalysts for the efficient and selective reduction of carbon dioxide to carbon monoxide in aqueous electrolytes.
Abstract: A key challenge in the field of electrochemical carbon dioxide reduction is the design of catalytic materials featuring high product selectivity, stability, and a composition of earth-abundant elements. In this work, we introduce thin films of nanosized metal-organic frameworks (MOFs) as atomically defined and nanoscopic materials that function as catalysts for the efficient and selective reduction of carbon dioxide to carbon monoxide in aqueous electrolytes. Detailed examination of a cobalt-porphyrin MOF, Al2(OH)2TCPP-Co (TCPP-H2 = 4,4',4″,4‴-(porphyrin-5,10,15,20-tetrayl)tetrabenzoate) revealed a selectivity for CO production in excess of 76% and stability over 7 h with a per-site turnover number (TON) of 1400. In situ spectroelectrochemical measurements provided insights into the cobalt oxidation state during the course of reaction and showed that the majority of catalytic centers in this MOF are redox-accessible where Co(II) is reduced to Co(I) during catalysis.

681 citations


4


Journal ArticleDOI
TL;DR: DFT calculations enlightened that the specific interaction between Ag nanoparticle and the anchoring agents modified the catalyst surface to have a selectively higher affinity to the intermediate COOH over CO, which effectively lowers the overpotential.
Abstract: Selective electrochemical reduction of CO2 is one of the most sought-after processes because of the potential to convert a harmful greenhouse gas to a useful chemical. We have discovered that immobilized Ag nanoparticles supported on carbon exhibit enhanced Faradaic efficiency and a lower overpotential for selective reduction of CO2 to CO. These electrocatalysts were synthesized directly on the carbon support by a facile one-pot method using a cysteamine anchoring agent resulting in controlled monodispersed particle sizes. These synthesized Ag/C electrodes showed improved activities, specifically decrease of the overpotential by 300 mV at 1 mA/cm2, and 4-fold enhanced CO Faradaic efficiency at −0.75 V vs RHE with the optimal particle size of 5 nm compared to polycrystalline Ag foil. DFT calculations enlightened that the specific interaction between Ag nanoparticle and the anchoring agents modified the catalyst surface to have a selectively higher affinity to the intermediate COOH over CO, which effectivel...

390 citations


Journal ArticleDOI
02 Jul 2001-Angewandte Chemie
TL;DR: A Highly active, time stable, and water resistant, Hombikat TiO2 supported Mn catalyst has been developed for the selective reduction of NO by NH3.
Abstract: A Highly active, time stable, and water resistant, Hombikat TiO2 supported Mn catalyst has been developed for the selective reduction of NO by NH3 [Eq. (1)]. The analogous Cu and Cr supported catalysts also provide 100 % N2 selectivity at ≤120°C. Lewis acidity, redox properties, and a high surface metal oxide concentration are essential for good catalytic performance.

375 citations


Journal ArticleDOI
TL;DR: The catalytic activity of Sn-Beta zeolite in the Meerwein-Ponndorf-Verley reduction of carbonyl compounds with secondary alcohols was performed with quantitative yields to the corresponding alcohol.
Abstract: The catalytic activity of Sn-Beta zeolite in the Meerwein−Ponndorf−Verley (MPV) reduction of carbonyl compounds with secondary alcohols was performed with quantitative yields to the corresponding alcohol. This heterogeneous catalyst exhibits activities and selectivities not observed before with other Me-zeolites.

337 citations


Journal ArticleDOI
Abstract: A range of alumina-supported platinum catalysts have been prepared and investigated for the selective reduction of nitrogen monoxide in the presence of a large excess of oxygen. Steady-state microreactor experiments have demonstrated that these catalysts are very active and selective for the reduction of nitrogen monoxide by propene at temperatures as low as 200°C. There does not appear to be a simple correlation between the activity for nitrogen monoxide reduction and the platinum surface area. Instead it is found that there is a very good inverse correlation between the maximum nitrogen monoxide reduction activity and the temperature. The most active catalysts for selective nitrogen monoxide reduction are those that generate activity at the lowest temperature. The technique of temporal analysis of products (TAP) has been used to obtain detailed mechanistic data about the selective nitrogen monoxide reduction reaction on an alumina-supported platinum catalyst. Using carbon monoxide, hydrogen or propene as reductant it has been demonstrated that the predominant mechanism for selective nitrogen monoxide reduction involves the decomposition of nitrogen monoxide on reduced platinum metal sites, followed by the regeneration of the active platinum sites by the reductant. In the decomposition step it has been shown that oxygen from nitrogen monoxide is retained on the surface of the platinum and blocks the surface for further adsorption/reaction of nitrogen monoxide; it has been observed that oxidised platinum catalysts are not active for the nitrogen monoxide reduction reaction. Under typical operating conditions, propene is a far more efficient reductant than either carbon monoxide or hydrogen. The greater efficiency of propene as a reductant is explained on the basis of the additional reducing power of the propene molecule, which can react with as many as nine adsorbed oxygen atoms, ensuring that 'patches' of reduced platinum are available for nitrogen monoxide adsorption/reaction. A small additional activity of reduced platinum in the presence of propene, which is not observed when carbon monoxide or hydrogen is used as reductant, has been explained on the basis of a second mechanism involving the carbon-assisted decomposition of nitrogen monoxide at sites on the reduced platinum adjacent to adsorbed carbon-containing moieties, believed to be fragments from adsorbed propene molecules. A model for the selective reduction of nitrogen monoxide on alumina-supported platinum catalysts is presented which is capable of explaining all the results obtained in this work and in the published literature on this subject.

336 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20221
202132
202034
201931
201839
201728

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Topic's top 5 most impactful authors

Hideaki Hamada

31 papers, 864 citations

Masaaki Haneda

27 papers, 650 citations

Yoshiaki Kintaichi

23 papers, 816 citations

Akira Obuchi

10 papers, 341 citations

Wolfgang Grünert

7 papers, 770 citations