Reduction of SO2 by CO on CnAun (n=4, 8 and 16) Clusters: A Computational Study

Mohan Tiwari and C. N. Ramachandran*

*Email: ramcnfcy[at]iitr.ac.in, *Phone: +91-1332284773

Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India

 

Sulphur dioxide (SO2) is an environmentally hazardous gas produced during various industrial processes such as the combustion of fuels. It is emitted directly to the atmosphere leading to air, water and soil pollution. Removal of SO2 and CO from atmosphere is a challenge. Keeping this in mind, we studied the catalytic reduction of SO2 by CO in presence of different types of mixed carbon-gold clusters using dispersion corrected density functional method. The clusters C4Au4, C8Au8 and C16Au16 (at bridge and terminal gold atoms) showed good catalytic activity towards the reduction of SO2 by CO with the maximum activation energy barrier of 41.85 kcal/mol, 53.87 kcal/mol and 32.12 kcal/mol (bridge) and 33.32 kcal/mol (terminal), respectively. The desorption energy for the final product COS is lower than the above activation energy suggesting that these clusters are free from sulphur poisoning. The reduction of SO2 by CO in presence of these clusters is exothermic. The rate determining step of the reaction in presence of the above clusters is also determined.

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