Investigating the Electrochemical Reduction of Nitrate to Ammonia on Single- Atom Catalysts via Operando X-ray Absorption Spectroscopy

Here we aim to provide a fundamental understanding of the complex changes occurring in the local electronic and geometric structures of electrocatalysts active for the nitrate reduction reaction (NO3RR) under real working conditions via operando X-ray absorption spectroscopy (XAS). The electrocatalyst materials under investigation are transition metal single-atom catalysts (SACs) embedded in a nitrogen-doped carbon support (Cu-NC and Fe-NC) that are able to efficiently reduce nitrate to ammonia, a valuable chemical product that is used heavily in the agricultural industry. By investigating these materials in several different pH-environments, we can gain much-needed insight into the electronic and structural changes that dictate the electrocatalytic behavior, which will ultimately help guide the rational design of NO3RR electrocatalysts.