Selective reduction

About: Selective reduction is a research topic. Over the lifetime, 1394 publications have been published within this topic receiving 29090 citations. The topic is also known as: multifetal pregnancy reduction & Pregnancy Reduction, Multifetal.

Visible-Light Photoredox Catalysis: Selective Reduction of Carbon Dioxide to Carbon Monoxide by a Nickel N-Heterocyclic Carbene–Isoquinoline Complex

Abstract: The solar-driven reduction of carbon dioxide to value-added chemical fuels is a longstanding challenge in the fields of catalysis, energy science, and green chemistry. In order to develop effective CO2 fixation, several key considerations must be balanced, including (1) catalyst selectivity for promoting CO2 reduction over competing hydrogen generation from proton reduction, (2) visible-light harvesting that matches the solar spectrum, and (3) the use of cheap and earth-abundant catalytic components. In this report, we present the synthesis and characterization of a new family of earth-abundant nickel complexes supported by N-heterocyclic carbene-amine ligands that exhibit high selectivity and activity for the electrocatalytic and photocatalytic conversion of CO2 to CO. Systematic changes in the carbene and amine donors of the ligand have been surveyed, and [Ni((Pr)bimiq1)](2+) (1c, where (Pr)bimiq1 = bis(3-(imidazolyl)isoquinolinyl)propane) emerges as a catalyst for electrochemical reduction of CO2 with the lowest cathodic onset potential (E(cat) = -1.2 V vs SCE). Using this earth-abundant catalyst with Ir(ppy)3 (where ppy = 2-phenylpyridine) and an electron donor, we have developed a visible-light photoredox system for the catalytic conversion of CO2 to CO that proceeds with high selectivity and activity and achieves turnover numbers and turnover frequencies reaching 98,000 and 3.9 s(-1), respectively. Further studies reveal that the overall efficiency of this solar-to-fuel cycle may be limited by the formation of the active Ni catalyst and/or the chemical reduction of CO2 to CO at the reduced nickel center and provide a starting point for improved photoredox systems for sustainable carbon-neutral energy conversion.

Alumina-supported silver catalysts for the selective reduction of nitric oxide with propene and oxygen-containing organic compounds

Abstract: The selective catalytic reduction of nitric oxide with propene and oxygen-containing organic compounds over several alumina-supported metal catalysts was investigated. Alumina-supported silver catalysts showed high activities in the presence of water and excess oxygen, while water vapor significantly decreased the activities of alumina and Co/Al2O3 which were highly active in the absence of water. It was also found that oxygen-containing organic compounds such as ethanol and acetone were more effective than propene in reducing nitric oxide over Ag/Al2O3 in the presence of water and excess oxygen.

Selective reduction of nitrogen oxides with hydrocarbons over solid acid catalysts in oxygen-rich atmospheres

Abstract: Highly selective reduction of nitrogen oxides to dinitrogen occurs to a high level in oxygen-rich atmospheres by using a small amount of propane as a reducing agent over alumina, silica-alumina, titania and zirconia catalyst. Judging from the data of activity and ammonia TPD measurement on a series of silica-alumina catalysts, acidity is suggested to be one of the main factors that determine catalytic activity.