Schematic showing three potential surface phases of catalysts upon removal of catalyst condition after catalysis.
Photo and CAD of HT-NAP-STM system in Tao group. (a) CAD drawing of the whole system (courtesy of SPECS Surface Nano Analysis GmbH). (b) Photo of the whole HT-NAP-STM system.
Concept of catalysis reactor of HT-NAP-STM. (a) Schematic of building a flow reactor for simulating catalysis study. (b) CAD of the HT-NAP cell (courtesy of SPECS Surface Nano Analysis GmbH). (c) Photo of catalysis reactor when it is open to UHV environment. (d) Photo of catalysis reactor when gas is filled in the reactor.
Shielding dome and sample heating. (a) Shielding dome separating hot gas in catalysis reactor from STM room through an aperture for approaching and retracting tip. (b) Heating sample through irradiation from UHV to sample in a reactive environment.
STM image of HOPG collected in air. (a) 200 Å × 200 Å. (b) 25 Å × 25 Å.
STM images of graphene grown on Ru(0001). Both images were collected when sample was at 700 K in UHV. (a) 100 Å × 100 Å. The large spots form a Moire pattern. The area marked with a rectangle box is O(2 × 2) formed at step edge of Ru(0001). (b) 74 Å × 74 Å. The large, bright feature forms the Moire pattern. Each bright spot in (b) is one carbon atom of graphene grown on Ru(0001). (Courtesy of SPECS Surface Nano Analysis GmbH.)
STM images of model catalyst Pt(111) in 1 Torr CO at room temperature. (a) 150 Å × 150 Å. (b) 250 Å × 250 Å; size of inset: 40 Å × 40 Å.
STM images of graphene grown on Ru(0001). These images were taken when sample was at 500 K in 25 Torr N2 gas. (a) Large scale image of graphene on Ru(0001): 1700 Å × 1700 Å. Bright spots form Moire pattern. (b) Atom-resolved image of graphene at 500 K in 25 Torr N2 gas. (Courtesy of SPECS Surface Nano Analysis GmbH.)
Time-dependent restructuring of atoms at edge of Pt(111) terraces in 20 Torr CO at room temperature. (a) Pt(111) in 20 Torr CO at time to; size: 430 Å × 430 Å. (b) Same area of Pt(111) as that in (a) in 20 Torr CO at time to+ 1 min; size: 430 Å × 430 Å. (c) Enlargement of structural feature at to; 130 Å × 130 Å. (d) Enlargement of structural feature of the same area as (c) at to + 1 min; 130 Å × 130 Å. A comparison between (c) and (d) clearly showed the formation of Pt nanoclusters at edge of terraces within 1 min.
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