The Ammonia Adsorption and Desorption Behavior of Nafion.

The electrochemical nitrogen reduction reaction (eNRR) for electrochemical ammonia (NH) synthesis is considered a promising alternative to the energy-intensive and highly CO-emitting Haber-Bosch process. In numerous experiments, the Nafion membrane has been used as an electrolyte or separator. However, Nafion adsorbs and desorbs NH, leading to erroneous measurements and making reproducibility extremely difficult. This study systematically investigates the interaction between NH and Nafion, underscoring the strength of the interaction between ammonium-ions (NH) and protons (H). We found that minute quantities of synthesized NH are prone to persist within the membrane, albeit without affecting the ion conductivity and resistivity of Nafion. Consequently, the removal of NH from the membrane can occur under conditions where synthesis is not viable. The objective of this work is to heighten awareness regarding the interaction between NH and Nafion and contribute to the attainment of reliable and reproducible outcomes in eNRRs.