DFT study of catalytic activity of an ultrathin TiO2(110) layer covering Au(112): O2 activation, CO oxidation, and replacing Au with Ag

• CO oxidation over a rutile(110) layer covering Au(112) has been examined by DFT.
• O2 adsorbs and activates on pentacoordinate Ti due to electron transfer via oxide.
• O2 adsorption weakens with increasing oxide thickness and O2 coverage.
• Barriers to reaction with CO(g) are ~ 0.6 eV for ad-O2 and ad-O.
• O2 is similarly activated on Au/rutile(110), rutile(110)/Au, and rutile(110)/Ag.

As a model of Au-titania core-shell catalysts, an ultrathin rutile TiO2(110) layer inversely supported on Au(112) has been examined by DFT. O2 adsorbs and activates on the pentacoordinate Ti site of rutile(110) as O2 π* orbitals accept electronic charge from the Au support via the oxide, as was found for Au/TiO2. O2 reacts with CO to yield CO2 and O, which then reacts with CO to yield CO2 (barrier ~ 0.6 eV). O2 adsorption weakens with increasing O2 coverage and oxide thickness. The reactivity of O2 changes negligibly even if we replace Au with Ag.

Figure optionsDownload as PowerPoint slide