Direct Observation of Nanoscale Pt Electrode Agglomeration at the Triple Phase Boundary

Abstract

Nanoporous platinum electrode thin films were delaminated from yttria-stabilized zirconia (YSZ) substrates via double cantilever beam delamination to reveal the structure located at the interface between electrode and electrolyte. The thermally driven morphological evolution between the electrode top surface and the substrate contact interface of agglomerated nanoporous platinum thin films were compared. We found the temperature required for significant agglomeration to occur was approximately 100 °C higher at the electrolyte contact interface side than at the top surface side. Judging the reaction active site from the electrode top surface could be inaccurate because higher resistance of thermal agglomeration at the interface could retain the reaction active site during fuel cell operation.

Ridge‐Valley Nanostructured Samaria‐Doped Ceria Interlayer for Thermally Stable Cathode Interface in Low‐Temperature Solid Oxide Fuel Cell

“…The as‐deposited Pt grains show an average width of ∼15 nm (Figure S5) and the Pt grains on single‐crystal YSZ substrate coalesce with each other after operation for 20 h at 450 °C, causing a significant increase in the average grain width to ∼71 nm (Figure a). In the nanoSDC sample however, the bottom part of columnar Pt grains appears to be much more intact than the top surface of the Pt grains after operation (Figure b), and shows the presence of nanopores (white dotted arrows in the inset image) . By virtue of a hindered coarsening at the Pt‐nanoSDC interface, nanoscale pores survive even after prolonged operation at elevated temperatures (inset image of Figure b), which helps to maintain the TPB density, and consequently, the electrochemical performance.…”

Low temperature micro solid oxide fuel cells with proton-conducting ceramic electrolytes

“…To test the functionality of the nanostructured BSCF thin film as a SOFC cathode at temperatures below 500 • C, BSCF thin film was deposition on a 200 µm-thick (100) single crystal YSZ, with the typical nanoporous Pt thin film deposited by RF sputtering as an anode [110]. A reference sample with nanoporous Pt cathode is fabricated and tested with the same condition.…”

Improving the thermal stability of nanoporous metal electrode thin films for low temperature solid oxide fuel cells

“…It is reported the thermallydriven morphological evolution between the top surface and the substrate contact interface of agglomerated nanoporous Pt electrode using double cantilever beam technique and found that the temperature required for significant agglomeration to occur was approximately 100 °C higher at the electrolyte contact interface side than at the top surface side. 39 This is because the unbounded surface of Pt is free to migrate under the thermally driven effect whereas the bonded interfacial Pt to the electrolyte experienced a constraint to migrate. 39 This reported work further clearly informed us that the thermal agglomeration behaviors are different from various part of the thin film electrode Figure 2.15 The Pt/YSZ/O2: interfaces and factors controlling the electrochemical behavior 52 Following sessions will discuss the work has been done for improving the thermal stability of nanoporous Pt electrode at high temperatures.…”

“…39 This is because the unbounded surface of Pt is free to migrate under the thermally driven effect whereas the bonded interfacial Pt to the electrolyte experienced a constraint to migrate. 39 This reported work further clearly informed us that the thermal agglomeration behaviors are different from various part of the thin film electrode Figure 2.15 The Pt/YSZ/O2: interfaces and factors controlling the electrochemical behavior 52 Following sessions will discuss the work has been done for improving the thermal stability of nanoporous Pt electrode at high temperatures. The discussed segments are categories as:…”

“…Platinum clusters begin to agglomerate from 300 °C annealing and much severe at higher temperatures. 39 Clusters and grains of platinum electrode grow exponentially after annealing beyond 400 °C, 49 which result in forming a larger gap between platinum clusters. The microstructure and morphology of platinum electrodes suffer agglomeration which may arise from Ostwald ripening.…”