In Situ Stress and Nanogravimetric Measurements During De-Alloying of PtCu Thin-Film Electrode

Enhanced catalytic activity of de-alloyed PtCu electrodes towards oxygen reduction reaction had been demonstrated in thin-film and core-shell geometries. The enhancement in catalytic activity is typically attributed to strained Pt layer (in thin-film electrodes) and Pt shell (in core-shell electrodes). The magnitude and the nature (compressive/tensile) of the strain on de-alloyed Pt were estimated thus far using lattice-constant measurements (via X-ray diffraction) on de-alloyed electrodes. In this work, we report real-time stress and nano-gravimetric measurements made during de-alloying of thin-film PtCu electrodes. In situ stress measurements were made using cantilever-deflection method, and gravimetric measurements were made using an electrochemical quartz crystal nanobalance.