NSF-DFG Echem: CAS: Spin-polarized electron currents for spin-selective electrocatalysis

With funding from the NSF Division of Chemistry, this research program involving Professor David Waldeck of the University of Pittsburgh and collaborators at the University of Münster (Germany) will explore the use of spin-polarized electrons to improve the chemical selectivity, and energy efficiency, in electrocatalysis. By building on ideas from the chiral induced spin selectivity effect, the proposed research will develop new electrode materials and electrode designs for generating spin polarized electrons and evaluate their performance as electrocatalysts.

The idea that chiral catalysts and chiral electrodes can be used to generate spin-polarized electron currents which can then be used to promote particular chemical reaction pathways represents a fundamentally new approach for electrocatalysis and electrosynthesis. Because the oxygen evolution reaction has been widely studied with achiral electrocatalysts, is critically important for energy technologies, and involves the production of diatomic oxygen (which has two unpaired electron spins), it will be used as a model system to examine the importance of spin polarized electron currents in electrocatalysis.

Students involved in this research will have the opportunity to engage in exchange between the US and German institutions. The team will conduct outreach activities involving K-12 students in the Pittsburgh area that promote interest in STEM fields.

This collaborative research project of Professor David Waldeck of the University of Pittsburgh and collaborators at the University of Münster (Germany) has three major thrusts. In each case, the extent of spin-polarized electron currents will be correlated with the selectivity and/or efficiency of electrocatalysis. Thrust 1 will investigate a range of chiral metal oxides, whose achiral analogues are known to be good catalysts for the oxygen evolution reaction.

Starting with simple chiral metal oxides and continuing with bilayer and doped composites the electrocatalysts spin-filtering properties and electrocatalytic performance will be evaluated and contrasted with their achiral analogues. Thrust 2 will develop composite materials in which achiral electrocatalysts are imbedded in a chiral support matrix to impart spin polarization and hence selectivity for triplet oxygen production on oxygen evolution catalysts.

Thrust 3 will create and develop chiral metamaterials for use as electrocatalysts. Using nanolithography methods, the team will fabricate electrocatalytic films comprising nanoscale metal (or metal oxide) helices that couple light energy into the catalyst and generate spin polarized electrons to drive the electrocatalysis. The research promises new insights into how chiral inorganic films can be designed to improve the generation of spin-polarized electron currents and how they can be employed as a new class of electrocatalysts.

Although the major effort will be applied to the oxygen evolution reaction, the insights gained for the production of spin-polarized electron currents are expected to be directly applicable to the design of electrocatalysts for other electrosynthesis reactions.

This research was funded under the NSF-DFG Lead Agency Activity in Electrosynthesis and Electrocatalysis (NSF-DFG EChem) opportunity NSF 20-578.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.