Robust catalyst assessment for the electrocatalytic nitrate reduction reaction

The electrocatalytic nitrate reduction reaction (NO3RR) can enable distributed conversion of waste to ammonia. Unlike the electrocatalytic dinitrogen reduction reaction, measurements of NO3RR often consider a fixed quantity of the nitrate anion in a batch system, presenting unique concerns for measurements of catalytic activity and selectivity. In addition, the sensitivity of kinetics and transport to electrolyte composition—where a diverse range of waste feedstocks are of interest—can have a notable impact on catalyst performance, hindering catalyst comparison. We highlight reaction complexities and advocate best practices for robust measurement of catalyst activity, selectivity, and Faradaic efficiency in this burgeoning field. Electrocatalytic nitrate reduction is widely studied, but under a range of conditions, with implications on catalyst performance. Here, the authors highlight potential pitfalls in comparing across (and within) existing literature and suggest approaches to assess electrocatalysts under common conditions.