Catalytic Hydrogenation of 1,3-Butadiene on Pd Particles Evaporated on Carbonaceous Supports: Particle Size Effect.

The catalytic activity of Pd aggregates obtained by atomic-beam vacuum deposition on carbonaceous substrates (amorphous carbon and graphite) has been measured in the 1,3-butadiene hydrogenation reaction. The particle sizes have been determined by TEM. Whatever the support, this reaction appears to be very size sensitive. Metal particles larger than 2.8 nm behave similarly to bulk palladium. The size effect is marked in the 2.8 to 1.4 nm specific diameter range. No activity remains for sizes below 1.4 nm. Highly marked deactivation processes are responsible for the main variations in the catalytic behavior.