AbstractReview: ESM: electrochemical strain microscopy, a scanning probe microscopy technique; 27 refs.

Electro-chemical strain microscopy (ESM) is a scanning probe microscopy technique that allows probing electro-chemical processes in nanoscale volumes.

Prospect of probing an electrochemical interface in situ, under actual operating conditions, and ability to map both the substrate (in terms of its electronic and short range atomic order) as well as the substrate-adsorbate interactions has tremendous technological implications. Synchrotron based x-ray absorption techniques offer such an opportunity as a consequence of the unique characteristics of the synchrotron source. These include higher: intensity (104 higher), collimation, polarization, and pulse time structure enabling true in situ interfacial measurements. X-ray absorption spectroscopy and scattering have recently evolved as a true in situ probe for electrochemical interface with both model and commercially relevant nano dispersed materials, providing a unique perspective on both the short and long range atomic order as well as the changes to the chemical environment of the absorber. This together with some new developments in the data analysis and modeling has now enabled more detailed perspective on the surface adsorbed species.

Abstract not Available.

Over the last few decades, researchers have made significant developments in producing more advanced electrocatalytic materials for power generation applications. For example, traditional fuel cell catalysts often involve high priced precious metals such as Pt. However, in order for fuel cells to become commercially viable, there is a need to reduce or completely remove precious metal altogether. As a result, a myriad of novel, unconventional materials have been explored such as chalcogenides, porphyrins, and organic-metal-macrocycles for low/medium temperature fuel cells as well as enzymatic and microbial fuel cells.

X-Ray Absorption Spectroscopy was utilized to study the poisoning of actual fuel cell catalysts under in situ conditions. The delta mu analysis technique of X-Ray Absorption Near Edge Structure on in situ Pt/C electrocatalysts is utilized at various potentials and concentrations of KCl. Comparison with FEFF8.0 calculated delta mu curves suggest a line shape consistent with 3-fold bonded Cl-. Inspection of the delta mu peak intensities implies dramatic suppression of Pt-O[H] adsorption in 10mM Cl-, but with both Cl- and O[H] adsorption competitively occurring in 1mM Cl-. This is the first time that XAS has been employed to probe the poisoning effects of Cl- on Pt electrocatalysts.

The dissolution/agglomeration of Ru and Pt from supported PtRu/C in an electrochemical cell, with potential cycling between 0.02 and 0.8 V, are reported. Two different commercial PtRu black catalysts (Johnson-Matthey and Tanaka) were utilized in 1M TFMSA and 0.3 M methanol and their properties compared. The Tanaka catalyst had relatively large RuOn islands on the surface; and underwent little Ru dissolution/agglomeration after 40 cycles, while the Johnson-Matthey catalysts with very small Ru islands underwent considerable Ru dissolution/agglomeration and thus, degradation of the catalyst. The Tanaka catalysts showed some Pt dissolution/agglomeration, but this appeared to increase the rate of CO oxidation (improve performance) after 40 cycles.