Electrochemical Energy Storage - Shannon Boettcher скачать в хорошем качестве

Electrochemical Energy Storage - Shannon Boettcher

Shannon Boettcher 2014-2015 Seminar Series December 3, 2014 Replacing fossil energy with renewables requires improved technology for energy storage. I will first present our work on understanding catalysts for the oxygen evolution reaction (OER) which limit the efficiency of H2 production through water electrolysis, a route to large-scale energy storage. We found Ni-Fe oxyhydroxides are the fastest known water oxidation catalysts under basic conditions when compared to others using a quantitative electrochemical-microbalance approach. In-situ electrical, photoelectron spectroscopy, x-ray diffraction, and electrochemical analyses on Ni1–xFexOOH films show that the reaction mechanism relies on the local electronic structure of a Ni-O(H)-Fe active site. Experiments with rigorous exclusion of Fe electrolyte impurities reveal that, contrary to common belief, pure NiOOH is a poor OER catalyst. FeOOH was found to be a poor electrical conductor, explaining its low “apparent” OER activity. Measurements on Co1–xFexOOH support the hypothesis that NiOOH and CoOOH provide a conductive host for the Fe-related active sites. In sum, these results establish a new activity trend for OER catalysts, opposite to previous ones, that informs catalyst design.