Effect of ozone pretreatment on low temperature CO oxidation catalysts

Effect of ozone pretreatment on low temperature CO oxidation catalysts 

Titanium dioxide supported gold catalysts exhibit excellent activity for CO oxidation even at temperatures as low as 90 K [1]. The key is the high dispersion of the nanostructured gold particles over the semiconducting Ti02 support. The potential applications of ambient temperature CO oxidation catalysts include air purifier, gas sensor and fuel cell [2]. This work investigates the effects of ozone pretreatment on the performance of Au/Ti02 for CO oxidation. 

The catal5fsts were tested for CO oxidation in a flow reactor using a 2.5 % CO in dry air mixture at a fixed flow rate of 200 seem. Thirty milligrams of the catalyst were used for each experimental run. The reaction was conducted at 298, 323, 373 and 473 K with 75 minutes duration at each temperature. The carbon monoxide conversion to carbon dioxide was monitored by an online gas chromatogr h equipped with a CTR-1 column and a thermal conductivity 

Sample Au loading (wt.%) Ti02 crystal size (nm) BET area Pre-treatment Au particle size before (after) reaction (nm) 

The Arrhenius plots of the CO conversion rate in Fig. 2 indicate that the activation energy for the Au/Nano-Ti02 catalysts is nearly zero. Haruta et al. [6] also reported similar observations. They suggest that this occurs when the CO adsorbed on gold particles reacts with adsorbed O2 on the support at the interfacial junction between the two surfaces. 

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