Promoting Electrocatalytic Activity of a Composite SOFC Cathode La\u3csub\u3e0.8\u3c/sub\u3eSr\u3csub\u3e0.2\u3c/sub\u3eMnO\u3csub\u3e3+δ\u3c/sub\u3e/Ce\u3csub\u3e0.8\u3c/sub\u3eGd\u3csub\u3e0.2\u3c/sub\u3eO\u3csub\u3e2-δ\u3c/sub\u3e with Molten Carbonates

The effect of molten carbonates (MCs) on polarization resistance (RP), a direct measure of oxygen reduction reaction (ORR) activity, of a composite La0.8Sr0.2MnO3+δ/Ce0.8Gd0.2O2-δ (LSM/GDC) solid oxide fuel cell (SOFC) cathode has been systematically investigated in this study over a temperature range of 550–650°C and partial pressure of oxygen (pO2) span of 10−3 ∼ 1 atm. It is shown that the LSM/GDC cathode, either in the pristine or MC-modified states, can be generally modeled by two consecutive parallel circuits consisting of a resistance and a constant phase element (CPE). The high-frequency RP(HF)//CPE(HF) component is related to a charge-transfer process, while the low-frequency RP(LF)//CPE(LF) counterpart is associated with a surface oxygen dissociative adsorption process. Incorporation of an adequate amount of MC significantly reduces RP(LF) by as much as a factor of 10. Studies on the dependence of RP on temperature and pO2 further reveal that the rate-limiting step of a LSM/GDC cathode has shifted from the original surface oxygen dissociative adsorption to the formation of an intermediate CO2 −4 species in the presence of MC

Molten Carbonates as an Effective Oxygen Reduction Catalyst for 550–650°C Solid Oxide Fuel Cells

We report the first study that investigates the use of molten carbonates as an effective catalyst to promote electrochemical oxygen reduction reaction (ORR) at the cathode of intermediate temperature solid oxide fuel cells (IT-SOFCs). A series of binary Li-K carbonate compositions were incorporated into the porous backbones of a commercial cathode assembled in symmetrical impedance cells for electrochemical characterization. Within the temperature range of 550–650◦C, we observed that the polarization and ohmic area-specific resistances of the original sample can be significantly reduced by the introduction of molten carbonates. A new ORR charge-transfer model involving two intermediate species CO5 2− and CO4 2− as the fast oxygen absorber and transporter, respectively, was presented as the mechanism for the facile ORR kinetics promoted by molten carbonates

The Rockbridge Group: Masters Along the Maury

For the last eight decades Rockbridge County, Virginia has served as an influential center for modern art. Neighbored by the capricious Maury River and nestled against the backdrop of the Blue Ridge Mountains, Rockbridge Baths significantly impacted the lives of four distinguished modern artists. Connected by ties of friendship or kin, the Rockbridge Group—Pierre Daura, Jean Hélion, Cy Twombly, and Sally Mann—drew inspiration and support from each other and from the people and places of the Rockbridge area. In 1928, Catalan modernist Pierre Daura (1896-1976) married Louise Blair, a Virginian studying in Paris. His friend, the French painter Jean Hélion (1904-1987), met Louise’s sister Jean at the Daura’s wedding, and they married in 1932. These two acclaimed European artists relocated to Rockbridge Baths in the later 1930s because of impending world war. Invigorated by the landscape and far from other influences, their distinct styles continued to evolve. Cy Twombly (1928-2011), born in the nearby town of Lexington, studied with Daura at his Rockbridge studio from the age of 12 until he left for college in 1946. Lexington native Sally Mann (b.1951), family friend of both Daura and Twombly, also drew from the vigorous landscape of the surrounding country in her dialectical work. This exhibition explores the question: What happens when the lives of four distinguished modern artists intertwine among the quiet, rolling foothills of the Blue Ridge Mountains