AVS 51st International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoP

Paper AS-MoP5
Comparative Analysis of a Pt/Rh Catalyst Sample with TOF-SIMS and Laser-SNMS

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: A. Schnieders, ION-TOF USA, Inc.
Authors: A. Schnieders, ION-TOF USA, Inc.
F. Kollmer, ION-TOF GmbH, Germany
M. Fartmann, Universität Münster, Germany
H.F. Arlinghaus, Universität Münster, Germany
V.S. Smentkowski, General Electric Global Research Center
Correspondent: Click to Email
In the field of catalysis, the analyst often needs to detect and image the distribution of trace quantities of species within the top most surface layer. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a well-established technique for such analysis. Unfortunately, quantitative TOF-SIMS analysis is not always easy to accomplish. Laser postionization of sputtered neutrals (Laser-SNMS) provides a higher sensitivity for many elements than TOF-SIMS, and in case of non-resonant multiphoton ionization (NRMPI), Laser-SNMS also provides for more uniform useful yields over the whole elemental range, thus enabling a more straight-forward way of quantification. In this paper, we compare the use of TOF-SIMS and Laser-SNMS with NRMPI for the analysis of a noble-metal treated stainless steal catalyst sample. The main analytical question focused on the determination of the lateral distribution of Pt and Rh on the surface of an actual (dirty) sample. Despite the relative low sensitivity for Pt, TOF-SIMS analysis enabled the determination of the lateral distribution of Pt and Rh on the surface. Quantification of these metals was possible by normalizing the corresponding ion intensities to those of a matrix signal. In comparison to TOF-SIMS, Laser-SNMS provided higher sensitivities for Pt and Rh as well as for other metals detected on the surface. To obtain accurate quantification, relative sensitivity factors for Pt and Rh were established on control samples. The lateral distributions thus measured confirmed those determined with TOF-SIMS. The similar results obtained with both techniques allowed establishing a procedure for quantification of TOF-SIMS results on similar samples.