As ingle-atom Pt 1 /CeO 2 catalyst formed by atom trapping (AT, 800 8 8Ci na ir) shows excellent thermal stability but is inactive for CO oxidation at lowt emperatures owing to over-stabilization of Pt 2+ in ah ighly symmetric square-planar Pt 1 O 4 coordination environment. Reductive activation to form Pt nanoparticles (NPs) results in enhanced activity;h owever, the NPs are easily oxidized, leading to drastic activity loss. Herein we showthat tailoring the local environment of isolated Pt 2+ by thermal-shock( TS) synthesis leads to ah ighly active and thermally stable Pt 1 /CeO 2 catalyst. Ultrafast shockwaves (> 1200 8 8C) in an inert atmosphere induced surface reconstruction of CeO 2 to generate Pt single atoms in an asymmetric Pt 1 O 4 configuration. Owing to this unique coordination, Pt 1 d+ in ap artially reduced state dynamically evolves during CO oxidation, resulting in exceptional low-temperature performance.C Oo xidation reactivity on the Pt 1 /CeO 2 _TS catalyst was retained under oxidizing conditions.

Hexagonal boron nitride (h-BN) catalyst has recently been reported to be highly selective in oxidative dehydrogenation of propane (ODHP) for olefin production. In addition to propene, ethylene also forms with much higher overall selectivities to C2-products than to C1-products. In this work, we report that the reaction pathways over the h-BN catalyst are different from the V-based catalysts in ODHP. Oxidative coupling reaction of methyl, an intermediate from the cleavage of C─C bond of propane, contributes to the high selectivities to C2-products, leading to more C2-products than C1-products over the h-BN catalyst. This work not only provides insight into the reaction mechanisms involved in ODHP over the boron-based catalysts but also sheds light on the selective oxidation of alkanes such as direct upgrading of methane via oxidative upgrading to ethylene or CHxOy on boron-based catalysts.

Direct oxidation of methane to value-added C1 chemicals (e.g. HCHO and CO) provides a promising way to utilize natural gas sources under relatively mild conditions. Such conversions remain, however, a key selectivity challenge, resulting from the facile formation of undesired fully-oxidized CO2. Here we show that B2O3-based catalysts are selective in the direct conversion of methane to HCHO and CO (~94% selectivity with a HCHO/CO ratio of ~1 at 6% conversion) and highly stable (over 100 hour time-on-stream operation) conducted in a fixed-bed reactor (550 °C, 100 kPa, space velocity 4650 mL gcat−1 h−1). Combined catalyst characterization, kinetic studies, and isotopic labeling experiments unveil that molecular O2 bonded to tri-coordinated BO3 centers on B2O3 surfaces acts as a judicious oxidant for methane activation with mitigated CO2 formation, even at high O2/CH4 ratios of the feed. These findings shed light on the great potential of designing innovative catalytic processes for the direct conversion of alkanes to fuels/chemicals.

We show for the first time that atomically dispersed Rh cations on ceria, prepared by ah igh-temperature atomtrapping synthesis,a re the active species for the (CO + NO) reaction. This provides ad irect link with the organometallic homogeneous Rh I complexes capable of catalyzing the dry (CO + NO) reaction. The thermally stable Rh cations in 0.1 wt %R h 1 /CeO 2 achieve full NO conversion with at urnover-frequency (TOF) of around 330 h À1 per Rh atom at 120 8 8C. Underdry conditions,the main product above100 8 8Cis N 2 with N 2 Ob eing the minor product. The presence of water promotes low-temperature activity of 0.1 wt %R h 1 /CeO 2 .I n the wet stream, ammonia and nitrogen are the main products above120 8 8C. The uniformity of Rh ions on the support, allows us to detect the intermediates of (CO + NO) reaction via IR measurements on Rh cations on zeolite and ceria. We also show that NH 3 formation correlates with the water gas shift (WGS) activity of the material and detect the formation of Rh hydride species spectroscopically.