First-Principles Computational Screening of Dopants to Improve the Deacon Process over RuO2

Deliberate doping of oxides is a promising route to further optimize their catalytic performance. To guide corresponding experimental endeavours we perform a density-functional theory based computational screening study for a wide range of metal dopant atoms in rutile RuO2. With a focus on the Deacon process, i.e. the catalytic oxidation of HCl to chlorine and water, we use the rate-controlling Cl desorption energy as a reactivity descriptor. As stability descriptors we employ the dopant surface segregation energy, as well as the dopant thermodynamic stability against precipitation into metal or bulk oxide grains. In the oxygen-rich conditions of the Deacon process, particularly the instability against oxide precipitation represents a strong limitation. In this respect, doping with Cu appears as an optimum compromise between stability and catalytic activity enhancement.