Volcano Relation for the Deacon Process over Transition-Metal Oxides

We establish an activity relation for the heterogeneous catalytic oxidation of HCI (the Deacon Process) over rutile transition-metal oxide catalysts by combining density functional theory calculations (DFT) with microkinetic modeling. Linear energy relations for the elementary reaction steps are obtained from the OFT calculations and used to establish a one-dimensional descriptor for the catalytic activity. The descriptor employed here is the dissociative chemisorption energy of oxygen. It is found that the commonly employed RuO2 catalyst is close to optimal, but that there could still be room for improvements. The analysis suggests that oxide surfaces which offer slightly weaker bonding of oxygen should exhibit a superior activity to that of RuO2.