Outlining Key Perspectives for the Advancement of Electrocatalytic Remediation of Nitrate from Polluted Waters

As nitrate pollution in groundwater continues to escalate, more is being discovered about the detrimental health implications associated with concentrated nitrate ingestion. Thus, there is a great necessity for the effective and sustainable remediation of nitrate from water. The electrocatalytic reduction of nitrate (ERN) has been identified as a promising technology with respect to selective product formation (N-2(g) and NH3/NH4+), adaptable instrument configurations, and compatibility with renewable energy sources. Electrocatalysts with appreciable selectivity for nitrate reduction to nitrogen gas are of great importance for drinking water applications. On the other hand, ammonia-selective catalysts are desirable for resource recovery. Traditional catalysts for ERN applications include expensive platinum group metals, which makes the widespread utilization of this technology economically unfavorable. Alternatively, research within the last five years has shown cost-effective catalytic materials such as bimetallic systems, graphitic composites, metal oxides, and metal sulfides exhibiting substantial activity/selectivity for ERN applications. Future ERN catalysts must not only express significant activity/selectivity but also be capable of stable and consistent performance under varying water chemistries. Combating electrocatalyst aging and fouling processes will be key in material design for catalysts capable of efficient remediation of nitrate from water under continuous long-term operation.