ABSTRACT
Antimony-doped tin dioxide (ATO) is considered a promising support material for Pt-based fuel cell cathodes, displaying enhanced stability over carbon-based supports. In this work, the effect of Sb segregation on the conductance and catalytic activity at Pt/ATO interface was investigated through a combined computational and experimental study. It was found that Sb-dopant atoms prefer to segregate toward the ATO/Pt interface. The deposited Pt catalysts, interestingly, not only promote Sb segregation, but also suppress the occurrence of Sb(3+) species, a charge carrier neutralizer at the interface. The conductivity of ATO was found to increase, to a magnitude close to that of activated carbon, with an increment of Sb concentration before reaching a saturation point around 10%, and then decrease, indicating that Sb enrichment at the ATO surface may not always favor an increment of the electric current. In addition, the calculation results show that the presence of Sb dopants in ATO has little effect on the catalytic activity of deposited three-layer Pt toward the oxygen reduction reaction, although subsequent alloying of Pt and Sb could lower the corresponding catalytic activity. These findings help to support future applications of ATO/Pt-based materials as possible cathodes for proton exchange membrane fuel cell applications with enhanced durability under practical applications.
ABSTRACT
LaCoO3 thin film was coated on Al2O3 single crystal by sol-gel route. Appropriate composition of precursors, chelating agents and the solvent put together into a flask and magnetically stirred on a magnetic stirrer. After having the red transparent solution, it was stirred for 12 hours before coating. Ultrasonically cleaned substrate is dipped into the solution and taken immediately into vertical furnace which is preheated at 550 degrees C. A dense amorphous film is coated on the substrate. Fired amorphous films are annealed at temperature between 900 degrees C and 1000 degrees C for 20 minutes in the air. Then coated film was characterized by means of XRD, AFM, and SEM. Conductivity of the film was measured to be -0.1819 for 881 degrees C for the log sigma value by assuming the thickness as
