(245b) Use of an Innovative Flow Reactor Configuration to Enhance Experimental Efficiency for Electrocatalytic Nitrate Reduction.

In the early 20^th century, the mass production of nitrate fertilizers enabled a population boom, however side effects of excess anthropogenic nitrate pollution include environmental damage and negative health effects in humans.

The three primary methods of nitrate remediation are physical separation, biological denitrification, and catalytic denitrification. Physical separation methods efficiently remove nitrate from water sources, but do not convert nitrate to other products. Biological denitrification converts nitrate to other products but suffer from sluggish rates and genetic drift of microbes alters their behavior over time. Catalytic denitrification allows for efficient and selective conversion of nitrate to desired products. A subtype of catalytic denitrification, the electrochemical nitrate reduction reaction (ENO₃RR) is especially promising as it can use renewably sourced electricity to drive the reaction and, unlike conventional thermal catalysis, can operate at standard temperature and pressure.

While ENO₃RR is promising, it has much room for improvement. An ideal ENO₃RR catalyst would be efficient and tolerant of conditions that could be encountered in nitrate pollution sources. ENO₃RR activity and selectivity can be tuned by modifying electrocatalyst composition, electrolyte composition, applied potential, and mass transport conditions. With so many variables, one quickly becomes limited by the rate of experimentation. In this talk we will present on the design and operation of a flow reactor system that allows rapid switching of reaction conditions and how this impacts experimental throughput.

As a case study, we use this system to study the effect of alkali cations on ENO₃RR. Research has shown that alkali cations can modify the activity and selectivity of ENO₃RR on tin electrodes, however, it is unclear whether these trends extend to other electrocatalysts. We will discuss the effects of alkali cations on various electrode materials for nitrate reduction to determine if cation effects are dependent or independent of electrode material.