Surface properties and oxygen reduction reaction on Pt and Pt-bimetallic surfaces

We present recent progress in the development of the fuel cell cathode materials on Pt3M (M =Ni, Co, Fe) alloys. The focus is related to the surface characterization, surface chem., kinetics of O redn. reaction (ORR) and reaction mechanism. We report new results for Pt3Fe surfaces which are compared to previous results for other Pt3M (M =Co, Ni) surfaces and for a polycryst. Pt electrode used as a std. for the kinetics of the ORR. All electrodes were prepd. in ultra-high vacuum by sputtering/annealing cycles, resp. Before the transfer to an electrochem. environment and into the ring disk position of an insertable rotating ring-disk arbor (0.1M HClO4), the PtM alloys were characterized in UHV by Auger electron spectroscopy (AES), Low Energy Ion Scattering Spectroscopy (LEISS) and UPS using synchrotron radiation source. After exposure to the electrolyte during potential controlled expts. alloy surfaces were transferred back to UHV in order to detect surface compn. The results from UHV characterization show different surface compn. after annealing in comparison to the bulk compn. (sputtered surface) due to segregation effect. Electrochem. characterization shows that the most of bimetallic alloy surfaces have higher specific activity for ORR than pure polycryst. Pt. The highest value established for ORR at 0.85 V vs. reversible H electrode (RHE) was measured for Pt-skin surface formed over Pt3Co and Pt3Fe alloys. [on SciFinder(R)]     «

We present recent progress in the development of the fuel cell cathode materials on Pt3M (M =Ni, Co, Fe) alloys. The focus is related to the surface characterization, surface chem., kinetics of O redn. reaction (ORR) and reaction mechanism. We report new results for Pt3Fe surfaces which are compared to previous results for other Pt3M (M =Co, Ni) surfaces and for a polycryst. Pt electrode used as a std. for the kinetics of the ORR. All electrodes were prepd. in ultra-high vacuum by sputtering/ann...     »

CAN 148:499427 52-2 Electrochemical, Radiational, and Thermal Energy Technology Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California at Berkeley, CA, USA. Journal 0161-6374 630-08-0 (Carbon monoxide); 1333-74-0 (Hydrogen); 7440-06-4 (Platinum); 7601-90-3 (Perchloric acid); 7782-44-7 (Oxygen); 39286-49-2 (Cobalt 25, platinum 75 (atomic)); 54727-55-8 (Iron 25, platinum 75 (atomic)); 98646-32-3 (Nickel 25, platinum 75 (atomic)) Role: TEM (Technical or engineered material use), USES (Uses) (surface properties and oxygen redn. reaction on platinum and platinum bimetallic surfaces)     «

CAN 148:499427 52-2 Electrochemical, Radiational, and Thermal Energy Technology Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California at Berkeley, CA, USA. Journal 0161-6374 630-08-0 (Carbon monoxide); 1333-74-0 (Hydrogen); 7440-06-4 (Platinum); 7601-90-3 (Perchloric acid); 7782-44-7 (Oxygen); 39286-49-2 (Cobalt 25, platinum 75 (atomic)); 54727-55-8 (Iron 25, platinum 75 (atomic)); 98646-32-3 (Nickel 25, platinum 75 (atomic)) Role: TEM (Technical or...     »