The condensation reaction of pyridine on TiO2(110): STM observation in the presence of the reactant atmosphere

The thermally activated reaction of pyridine was studied by STM on a TiO2(110)–(1×1) surface. The unexpected condensation of weakly physisorbed pyridine was found. The formation and growth of the product particles were monitored in-situ on the surface heated at reaction temperatures (300–400 K) in the presence of pyridine atmosphere. A physisorbed pyridine molecule was activated at 350 K to form an intermediate, probably a partially dehydrogenated or chemisorbed state of pyridine. The intermediates aggregated into larger particles of nm size. A gas-phase or physisorbed pyridine molecule is also directly involved in the particle growth reaction.