(Invited) Electrocatalytic Reduction of Nitrate: Insight from Manipulating Adsorbate Affinity

Abstract

Fertilizer use and fossil-fuel combustion has increased nitrate concentrations in many wastewaters and watersheds to levels that threaten environmental and human health. Consequently, treatment of nitrate-contaminated water is a growing area of energy consumption. Electrocatalytic nitrate reduction offers a distributable treatment solution also capable of producing value-added products (e.g. ammonium), using electrons as a reducing agent at ambient temperatures and pressures. However, nitrate reduction occurs at similar electrochemical potentials to water reduction, reducing the Faradaic efficiency particularly in dilute nitrate concentrations characteristic of wastewater. Here we consider how changing a catalysts’ affinity for nitrate (via oxide supports) or its relative affinity for protons (via electronic structure) impact activity and selectivity of the electrocatalytic nitrate reduction reaction in neutral media.