This study highlights the importance of following a strict protocol for Nafion membrane pretreatment for electrochemical nitrogen reduction reaction experiments. Atmospheric ammonia pollution can be introduced to the experimental setup through membranes and interpreted falsely as catalysis product from N2. The sources of ammonia contamination vary drastically between locations worldwide and even within the same location between days depending on temperature, wind direction, fertilizer use, and manure accumulation in its vicinity. The study shows that significant amounts of ammonium is accumulated in the membranes after commonly practiced pretreatment methods, where the amount depends on the ammonia concentration in the surrounding of the experiment. Therefore, we introduce a new pretreatment method which removes all the ammonium in the membrane. The membranes can be stored for several days but a short final step in the method needs to be carried out right before NRR experiments.

No abstract

This study highlights the importance of following a strict protocol for Nafion membrane pretreatment for electrochemical nitrogen reduction reaction experiments. Atmospheric ammonia pollution can be introduced to the experimental setup through membranes and interpreted falsely as catalysis product from N2. The sources of ammonia contamination vary drastically between locations worldwide and even within the same location between days depending on temperature, wind direction, fertilizer use, and manure accumulation in its vicinity. The study shows that significant amounts of ammonium is accumulated in the membranes after commonly practiced pretreatment methods, where the amount depends on the ammonia concentration in the surrounding of the experiment. Therefore, we introduce a new pretreatment method which removes all the ammonium in the membrane. The membranes can be stored for several days but a short final step in the method needs to be carried out right before NRR experiments.

Ammonia (NH3) production via the electrochemical nitrogen reduction reaction (NRR) is a promising method for sustainable generation of this important chemical. Efforts are ongoing in finding an efficient, stable, and selective catalyst that will enable the reaction. However, progress is hindered in the field due to lack of reproducibility, most likely a consequence of reports of false‐positive results due to improper measurement control and methods. In this study, we explore the NRR activity of a promising class of single atom catalysts, transition metal‐nitrogen‐carbon (M‐N‐C) electrocatalysts. Using a state‐of‐the‐art in‐line ammonia quantification methodology, with detection limit as low as 1 ppb for ammonia, we show that single atom Nb and Fe embedded in a stable carbon and nitrogen framework do not electrochemically reduce N2 to NH3. Critically, this demonstrates that our experimental setup with in‐line sequential injection analysis successfully excludes ammonia contamination from the gas supply and atmospheric sources, allowing for thorough and high‐throughput examination of potential NRR catalysts.

No abstract