Collaborative Research: CAS: Graphite-Conjugated Macrocycle Electrocatalysts for Nitrate Reduction

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Yulia Pushkar of Purdue University, Professor Jeremy Smith of Indiana University and Associate Professor Elena Jakubikova of North Carolina State University are studying catalysts that will use electrical energy for the conversion of aqueous nitrate to useful or benign products such as ammonia. Nitrate is a water pollutant that occurs largely as a result of agricultural fertilizer use.

The proposed research takes a first step to addressing this problem through the development of robust and efficient electrocatalysts that to convert nitrate to desirable compounds via reductive chemistry. Scientific insights gained through these studies will likely impact the development of other electrocatalysts for other useful electrochemical conversions.

Outreach activities include a partnership with the public radio program “A Moment of Science” and the development of YouTube videos on the nitrogen cycle.

This project combines the expertise of three research groups in synthetic, electrochemical, spectroscopic, and computational studies on the development of environmentally relevant electrocatalysts. A modular class of graphite-conjugated macrocyclic complexes will be characterized by a range of physical methods, including synchrotron-based X-ray spectroscopy.

Together with experimentally calibrated electronic structure calculations, these data will provide information on the coordination environment, structure, and electron configuration of the metal ion. Redox properties will be characterized by electrochemical measurements, with computational methods providing detailed insights into the electronic structures of different oxidation states.

In addition to standard electrochemical and computational methods for mechanistic interrogation, in situ spectroscopic characterization is expected to provide detailed information on the nature of intermediates in the catalytic cycle. Mechanistic investigations into materials that are selective for nitrate reduction will provide insight that is expected to aid in the rational design of catalysts having improved activity.

Outreach activities are to including a partnership with a public radio broadcast and the development of publicly accessible educational videos are expected to reach a wide audience and inform the public broadly about electrocatalysis and its utility in developing environmentally beneficial reductive nitrogen chemistry.

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.