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Iridium metallic4/10/2024 Structural evolution of atomically dispersed Pt catalysts dictates reactivity. Homogeneity of surface sites in supported single-site metal catalysts: assessment with band widths of metal carbonyl infrared spectra. Introduction: surface chemistry of oxides. The isoelectric points of solid oxides, solid hydroxides, and aqueous hydroxo complex systems. Surface coordination chemistry of atomically dispersed metal catalysts. Coordination chemistry of atomically dispersed catalysts. Single-atom catalysts: are all sites created equal? ACS Energy Lett. Single sites in heterogeneous catalysts: separating myth from reality. Atomically dispersed platinum supported on curved carbon supports for efficient electrocatalytic hydrogen evolution. General synthesis and definitive structural identification of MN 4C 4 single-atom catalysts with tunable electrocatalytic activities. Photochemical route for synthesizing atomically dispersed palladium catalysts. Thermally single-atom platinum-on-ceria catalysts via atom trapping. Low-temperature hydrogen production from water and methanol using Pt/α-MoC catalysts. Atomically dispersed Fe 3+ sites catalyse efficient CO 2 electroreduction to CO. A heterogeneous single-atom palladium catalyst surpassing homogeneous systems for Suzuki coupling. Identification of single-site gold catalysis in acetylene hydrochlorination. Single-atom catalysis of CO oxidation using Pt 1/FeO x. Chemical synthesis of single atomic site catalysts. The similar activities for high- and low-loading catalysts suggest that iridium sites, whether isolated or in the form of clusters (for example Ir 3), have similar activity, consistent with the involvement of surface dynamics. These species display unique catalytic properties in the coupling reaction of benzene and ethylene to form styrene, a reactivity that contrasts with conventional homogeneous and heterogeneous iridium catalysts that yield ethylbenzene. Here, using single-crystalline MgO(111) two-dimensional nanosheets and a surface organometallic chemistry method, we describe the formation of highly dispersed Ir(III) sites (isolated at 0.1 wt%, and Ir pairs and trimers at 1 wt%) with well-defined coordination structures. Yet, despite the observation of single atoms, understanding their coordination structures and developing structure–property relationships remains challenging due to the structural complexity of support surfaces. ![]() Discovery of the new elements was documented in a letter to the Royal Society on June 21, 1804.Single-atom catalysis is recognized as a frontier of heterogeneous catalysis for its efficient utilization of metals and the possibility to engender unusual reactivity. He named iridium after Iris (Ἶρις), the Greek winged goddess of the rainbow and the messenger of the Olympian gods, because many of the salts he obtained were strongly colored. He obtained dark red crystals by a sequence of reactions with sodium hydroxide and hydrochloric acid. Tennant, who had the advantage of a much greater amount of residue, continued his research and identified the two previously undiscovered elements in the black residue, iridium and osmium. Vauquelin treated the powder alternately with alkali and acids and obtained a volatile new oxide, which he believed to be of this new metal-which he named ptene, from the Greek word πτηνός ptēnós, "winged". In 1803, British scientist Smithson Tennant analyzed the insoluble residue and concluded that it must contain a new metal. The French chemists Victor Collet-Descotils, Antoine François, comte de Fourcroy, and Louis Nicolas Vauquelin also observed the black residue in 1803, but did not obtain enough for further experiments. Joseph Louis Proust thought that the residue was graphite. They always observed a small amount of a dark, insoluble residue. Discovery of iridiumChemists who studied platinum dissolved it in aqua regia (a mixture of hydrochloric and nitric acids) to create soluble salts.
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