(Lecture, May 23) Turning a cheap, poor catalyst into a cheap, excellent catalyst. Optimizing layered MnO-based materials for water oxidation using experiment and theory
May 19,2017 17:24:14 readCount:143

Title: Turning a cheap, poor catalyst into a cheap, excellent catalyst. Optimizing layered MnO-based materials for water oxidation using experiment and theory
Speaker: Dr. Michael J. Zdilla, Temple University
Time: 16:00-17:00p.m., May 23rd, 2017
Venue: Room 105, Shaw Engineering Building, Wushan Campus

Abstract:
Efficient catalytic water oxidation is an important reaction for the development of solar hydrogen as a source of green energy. Extraction of high energy electrons from water for the preparation of fuel leaves O2 as a byproduct. Nature boasts the only truly effective catalyst for this reaction, the oxygen evolving complex (OEC), a tetramanganese- calcium-oxo cluster. The exploration of solid-state manganese oxides inspired by (or possibly a primordial precursor to) this inorganic cluster is of interest for the chemical and electrochemical oxidation of water, and while promising catalysts have been discovered, an understanding of their active site structures and mechanisms has been elusive, precluding incremental improvements in design. This lecture is focused on the birnessite phase of MnO2, typically viewed as a poor water oxidation catalyst.
The Center for the Computational Design of Functional Layered Materials at Temple University is undertaking a combined experimental and theoretical approach where Density Functional Theoretical (DFT), and Molecular Dynamics (MD) computations inform and guide experimental approaches as to understand the functioning of, and thereby identify ways to improve the catalytic activity of these materials. Modification of birnessite by enrichment with Mn(III) defect sites, intercalated interlayer Co or Ni ions, and alloying of the layers with Co(III) have turned this relatively poor catalyst into one competitive with excellent IrO-, cobalt-oxide-, and double-layer-hydroxide-based catalysts. The discoveries have been guided by MD simulations which show enhanced geometric frustration of water enhances electron transfer rates, and DFT calculations which describe geometric features that optimize band structure for beneficial electronic conductivity and charge separation.


Announced by School of Chemistry and Chemical Engineering