Rate Measurements in Magnetoelectrocatalysis
Abstract
Electrochemists at the University of Iowa have demonstrated efficiency is significantly enhancements when micromagnets are added to a wide range of electrochemical systems and reactions. Micromagnets in batteries, fuel cells, photovoltaics, and supercapacitors increase rate by 40%. Energy, power, capacity, and efficiency are 40% higher. In electrochemical reactions, yet greater enhancements are observed. This includes environmentally and energetically important reactions such as the hydrogen evolution reaction (HER) and carbon monoxide oxidation. Impacts of magnetic modification depend on the magnetic properties of reactants, products, and electrodes. Throughout, micromagnets serve as catalysts, chemically unaltered over the course of the reaction, but driving increased rate. Efficiency of these reactions is set by the rate that electrons transfer between the electrode and reactant. In natural and man-made systems, electrocatalysts increase electron transfer rate. The micromagnets have proven surprisingly effective catalysts. Unlike micromagnets, electrocatalysts are rarely applicable across a wide range of systems and reactions. Why micromagnets drive catalysis may extend from classical ideas about electricity and magnetism. Electrochemistry is the study of systems at the juncture of chemistry and electrical phenomena. Common in physics is the knowledge that current is coupled to electric and magnetic fields and their gradients. The question arose as to whether introduction of magnetic fields and gradients to electrochemical systems increases electron transfer efficiency. The team at the University of Iowa defines these effects as magnetoelectrocatalysis. Their data collected across numerous electrochemical systems and reactions is consistent with a general magnetic effect that enhances electron transfer rates. Fundamentals of how magnetic fields and gradients impact electron transfers are not yet well resolved. Given fundamental models, magnetoelectrocatalysts can be more rapidly deployed in advanced technologies and natural phenomena better understood. The objective of this effort is to obtain more highly resolved measurements of electron transfer rates that will further quantify the magnetoelectrocatalytic effect and support or refute nascent models of magnetoelectrocatalysis. The effort exploits methods to measure faster electron transfer rates with greater precision. Square wave voltammetry (SWV) determines rates of electron transfer at electrode surfaces and in matrices that support electron hopping. SWV will determine electron transfer rates that are often more rapid than measurable by voltammetric methods thus far used. The main systems to be evaluated by SWV are the hydrogen evolution reaction and an academically useful matrix that supports electron hopping by transition metal complexes embedded in an ion exchange polymer. These measurements will be exploited to confirm micromagnets impact electron transfer events with negligible impacts on other electrochemical processes such as transport. Comparison of matrices composed of magnetized and demagnetized microparticles is important because the magnetized and demagnetized systems are chemically the same and differ only in the presence and absence of magnetic fields and gradients. Measurements of carbon monoxide oxidation are complicated by multistep chemical processes, but carbon monoxide electrochemistry will also be surveyed. The purpose of these studies are two fold: to further substantiate magnetic effects on electron transfer as a new and broadly applicable means of catalysis - magnetoelectrocatalysis - and to better understand the fundamental phenomena that drive electron transfer events. From fundamentals will evolve new catalytic processes, novel materials, better implementations of electron transfer events in health and medicine, and substantially enhanced electrochemical energy systems
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 01, 2019
- Source ID
- W911NF1910208
Entities
People
- Johna Leddy
Organizations
- Army Contracting Command
- United States Army
- University of Iowa