Self-recoverable Pd-Ru/TiO₂ nanocatalysts with ultrastability towards ethanol electrooxidation

Self-recoverable Pd-Ru/TiO2 nanocatalysts have been prepared by electrochemical stripping of Pd-Ru/TiO2 precursors. For the ethanol oxidation reaction (EOR), these Pd-Ru/TiO2 nanocatalysts are used as an anode catalyst. The characterization of catalysts via chronoamperometry has been repeated 15 times. After 15 stability tests, the Pd1Ru0.69/TiO2 nanocatalysts still achieve a factor of 9.4 enhancement at the residual current density (309.42 mA mgPd-1) for the EOR over commercial Pd/C catalysts (33.01 mA mgPd-1). From the 5th to 15th test, when each 10 000 s stability test is performed in a fresh ethanol electrolyte, the initial and residual current density of the catalysts could recover to the original or even better value in a few hours before performing another 10 000 s stability test. Herein, these Pd-Ru/TiO2 nanocatalysts with ultrastability towards ethanol electrooxidation are self-recoverable. Density functional theory calculations reveal that the introduction of oxophilic metal Ru and a TiO2 support into Pd-based catalysts and the synergistic effects between Ru and TiO2 have led to the ultrastability towards the EOR. The introduction of oxophilic metal Ru and a TiO2 support into catalysts can reduce the adsorption energy of OHads on the Pd-Ru/TiO2 nanocatalysts, and it will inhibit the COads produced and adsorbed on the Pd surface.