Abstract Title: GOALI: New Scanning Probe Methods for Imaging Local Activity in Electrocatalysts on Nanometer Length Scales
A key requirement for our nation's future energy infrastructure is an ability to efficiently interconvert chemical (fuel) and electrical forms of energy. Such interconversion is facilitated by using oxide electrocatalysts at high temperature, which provide highly active surfaces upon which molecules and electrons can interact. Unfortunately the factors governing activity and degradation of electrocatalysts are not very well understood. This project seeks to develop new scanning probe methods that can image in real time, and during operation at up to 500-600°C, where and when reactions occur on the surface, with nanometer resolution. This GOALI award brings together Professors Stuart Adler and Jiangyu Li with expertise in electrocatalysis and scanning probe methods at the University of Washington and Dr. Roger Proksch, head of the research staff at Asylum Research, a leading developer of scanning probe instruments to develop an advanced high-temperature scanning probe system. This instrument and the resulting research work will lead to major advances in how we study electrocatalysts, as well as provide key insights leading to new technological advances in electrocatalysis. The project will also provide advanced graduate education to two PhD students, provide research opportunities for undergraduates, and support the mentorship of Seattle-area K-12 students in pursuing a deeper scientific education.
A universal challenge facing development of high temperature electrocatalysts is a lack of fundamental understanding of physical and chemical rates at local length scales (10-50 nm). A growing body of research shows that the composition, structure, and properties of these materials near solid-solid or gas-solid interfaces deviate substantially from the bulk. The purpose of this GOALI is to develop scanning probe techniques (based on measurement of local lattice strain, conductivity, and surface work function) to quantify and image local rates in porous high-temperature electrocatalysts under in-situ conditions. This project seeks to 1) link strain, work function, and other locally measurable properties to variations in charged defect concentrations, 2) implement scanning probe techniques in-situ on working electrodes as witnesses of local dynamics, and 3) extend the current experimental capabilities to access higher temperatures (500-600°C). Ultimately, the active region of a porous electrode will be imaged as a function of variables, resulting in the extraction of basic information about relative rates of molecular reactions, surface transport, and bulk transport occurring at a local level near the electrode/electrolyte interface.
