title: Probing the H2-Induced Restructuring of Pt Nanoclusters by H2-TPD.
abstract: Metal clusters with sizes below 1 nm attract great scientific interest, but the main information on their properties still comes from quantum mechanics modeling and costly physical methods of limited availability. We have studied ultradispersed Pt/γ-Al2O3samples with temperature-programmed desorption (TPD) and complementary adsorption/desorption techniques and observed that the H2-TPD profile of Pt/γ-Al2O3is strongly dependent on the pretreatment conditions (0 < PH2≤ 1 bar; 200 K ≤ T ≤ 470 K). The results corroborate recent theoretical and spectroscopic studies predicting alterations in the structure of Pt nanoclusters under H2-treatment conditions but reveal that the restructuring needs to overcome continuous activation barriers and leads both to an increase in surface coverage and strengthening of the Pt-H bonds. This was interpreted as being a consequence of the strong interaction of Pt clusters with the support. The results extend insights into the behavior of supported metal particles and expand the potential of existing experimental techniques.
authors: Boreskov Institute of Catalysis SB RAS , Novosibirsk 630090, Russian Federation.
authors: Olga A
authors: OA
authors: Yakovina
authors: Boreskov Institute of Catalysis SB RAS , Novosibirsk 630090, Russian Federation.
authors: Alexander S
authors: AS
authors: Lisitsyn