Gold (Au)- and ceria (CeO2)-based catalysts are amongst the most active catalysts for the gas phase CO oxidation reaction. Nevertheless, nanosized Au and CeO2catalysts may encounter heat-induced sintering in thermochemical catalytic reactions. Herein, we report on the rational one-pot synthesis of ceria-reduced graphene oxide (CeO2-RGO) using a facile ethylenediamine (EDA)-assisted solvothermal method. Standalone RGO and free-standing CeO2were also prepared using the same EDA-assisted method for comparison. We then incorporated Au into the prepared samples by colloidal reduction and evaluated the catalytic activity of the different catalysts for CO oxidation. The RGO-supported CeO2surpassed the free-standing CeO2, exhibiting a 100% CO conversion at 285oC compared to 340oC in the case of CeO2. Interestingly, the RGO-supported Au/CeO2catalysts outperformed the Au/CeO2catalysts and achieved a 100% CO conversion at 76oC compared to 113oC in the case of Au/CeO2. Additionally, the Au/CeO2-RGO catalyst demonstrated remarkable room-temperature activity with simultaneous 72% CO conversion. This outstanding performance was attributed to the unique dispersion and size characteristics of the RGO-supported CeO2and Au catalysts in the ternary Au/CeO2-RGO nanocomposite, as revealed by TEM and XPS, among other techniques.
Cooperation of cerium oxide nanoparticles and soluble molecular catalysts for alcohol oxidation
Cerium oxide (ceria, CeO 2−x ) has been traditionally used as a catalyst support functionalized with metal nanoparticles or synthesized with metal dopants for a variety of applications ranging from catalytic converters to solid oxide fuel cells. In a departure from these typical heterogeneous motifs, we explore the interactions of nano-CeO 2−x systems with organometallic oxidation catalysts in organic solvents. Ceria is used here both as an organically-capped colloid and as an uncapped insoluble nanopowder. Both the colloid and nanopowder act as terminal oxidants by accepting hydrogen atoms from a ruthenium Noyori–Ikariya hydride complex. To our knowledge, this is the first demonstration that CeO 2−x can oxidize an organometallic hydride. Building on this concept, we show the uncapped CeO 2−x powder also acts as the terminal acceptor in catalytic alcohol dehydrogenation reactions, utilizing iridium pyridine sulfonamide catalysts under anaerobic and aerobic conditions. The coupling of homogeneous oxidation catalysts with cerium oxide demonstrates the versatility of CeO 2−x and a bridging of concepts in homogeneous and heterogeneous catalysis.
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- PAR ID:
- 10168380
- Date Published:
- Journal Name:
- Inorganic Chemistry Frontiers
- Volume:
- 7
- Issue:
- 6
- ISSN:
- 2052-1553
- Page Range / eLocation ID:
- 1386 to 1393
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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