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Catalysis and Catalysts - Mechanism of Catalysis Dissociative Chemisorption of H 2 on a Metal 0.2 0.4 0.60.8 distance, nm 2. chemisorption 1. physisorption.

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Presentation on theme: "Catalysis and Catalysts - Mechanism of Catalysis Dissociative Chemisorption of H 2 on a Metal 0.2 0.4 0.60.8 distance, nm 2. chemisorption 1. physisorption."— Presentation transcript:

1 Catalysis and Catalysts - Mechanism of Catalysis Dissociative Chemisorption of H 2 on a Metal 0.2 0.4 0.60.8 distance, nm 2. chemisorption 1. physisorption E diss 2 Ni s + 2 H Ni + H 2

2 Catalysis and Catalysts - Mechanism of Catalysis H 2 + 2 N s 2 Ni-H

3 Catalysis and Catalysts - Mechanism of Catalysis Free Valences On Metal Surfaces 12 87 9

4 Catalysis and Catalysts - Mechanism of Catalysis Even Pure Metal Particles have Different Sites

5 Catalysis and Catalysts - Mechanism of Catalysis NH 3 Synthesis Volcano curve Gas-phase process Catalysed process Potential energy (kJ/mol) N  3 H NH  2 H NH 2  H ½ N 2,ads  1½ H 2 ½ N 2 1½ H 2 N ads  3 H ads NH ads  2 H ads NH 2,ads  H ads NH 3,ads NH 3 < 24 31 28 276 ~ 160 ~ 130 96 46 1129 815 426

6 Catalysis and Catalysts - Mechanism of Catalysis Co oxidation over Ru 3.0 2.0 1.0 0.0 Reactioncoordinate Energy ( eV ) 1.64 0.30 0.85 0.66 CO + 1/2 O 2 CO +O ads CO ads +O CO 2

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