A High-Throughput Cell Design to Screen Bimetallic Catalysts for Electrochemical Nitrogen Reduction to Ammonia

Abstract

Ammonia is an important chemical used in the production of fertilizers and has the potential to become a green energy carrier. It is synthesized through the Haber-Bosch (HB) process, which involves nitrogen and hydrogen reacting at high temperature and pressure and consumes approximately 2% of the global energy supply. An alternative to this energy intensive process is the electrocatalytic nitrogen reduction reaction (NRR). The main challenge of this approach is the competing hydrogen evolution reaction (HER) that consumes most of the applied electricity, making the ammonia production inefficient. Based on the Sabatier principle, an ideal catalyst for the NRR would bind nitrogen and ammonia optimally, while hydrogen would be bound too strongly or too weakly, suppressing the HER. So far, no such catalyst has been found. A strategy that could lead to the discovery of a suitable catalyst is alloying, since materials with new adsorption properties can be created this way. The main goal of this project is to design an electrochemical cell that can be used for the screening of large numbers of bimetallic catalysts, increasing the chance of finding a suitable NRR catalyst. For this so-called high-throughput approach an electrochemical cell was designed that allows the screening of up to 16 catalysts in parallel. Furthermore, methods for sample preparation, characterisation and detection were developed that are compatible with a high-throughput technique