Carbon Monoxide Oxidation on Model Planar Titania Supported Platinum Nanoparticles Catalyst

Abstract

A high-throughput (parallel) thermographic screening methodology was developed to enable the measurements of the particle size and support influence on heterogeneous catalysts. A high throughput screening chip has been used to establish the catalytic activity of titania supported platinum nanoparticles catalyst for CO oxidation reaction. The catalytic activity of Pt nanoparticles between 1.3 to 7.8 nm has been investigated for CO conversion at a pressure of 0.11 and 1.1 mbar with O₂:CO ratio of 1:1 at 80 °C and 0.6, 1.1 and 2.4 mbar at O₂:CO ratio of 1:1 at 240 °C. At these experimental conditions, there was an increase in the TOF with decreasing particle size for instance, at 80 °C and O₂:CO ratio of 1:1, total pressure of 0.11 and 1.1 mbar, the TOF increased from 0.01 s^–1 to 0.171 s^–1 with decreasing Pt particle size from 7.8 to 1.3 nm, respectively. However, Pt nanoparticles catalyst displayed higher activity at higher temperature, for example, the TOF increased from 3.312 s^–1 to 4.355 s^–1 at O₂:CO ratio of 1:1, total pressure of 0.6 and 1.1 mbar, respectively, for Pt particle size of 1.3 nm in agreement with the previous reports. Results show that CO oxidation on titania supported Pt nanoparticles catalyst is particle size dependent. On the other hand, findings from XPS measurements show no major change in the particle size after the reaction thus, reflecting the stability of Pt particles. While there is no apparent consensus in the literature reports on the activity trend with particle size for this system, these findings are consistent with most of the previously reported findings.

Keywords: platinum; titania; nanoparticles; thermography; CO oxidation.