(437g) Enabling Nitrate Valorization to Ammonia through Electrocatalyst Design

Nitrate (NO₃^-) is a widespread surface and groundwater contaminant which if not treated cause adverse affects on human health such as methemoglobinemia (“blue baby syndrome”) and cancer. Electrocatalytic routes toward nitrate transformation have centered on remediation strategies. Electrocatalytic remediation occurs through a two-step process. First, nitrate reduction (NO₃RR) transforms nitrate to nitrite, and then nitrite reduction (NO₂RR) transforms nitrite to nitrogen gas. This approach produce no waste as nitrogen can be released into the atmosphere. Others routes toward nitrate transformation have centered on valorization strategies [2,3]. In this approach, electrocatalytic NO₃RR and NO2RR are performed on a catalyst, however, ammonia is the product of NO₂RR instead of nitrogen. Independent of the transformation path, choice of catalytic material to perform NO₃RR and NO₂RR reduction is imperative to achieve desirable activity and selectivity. NO₃RR electrocatalytic activity has been previously shown to be high on Cu, Sn, and In, which precious metals such as Pd and Pt show poor activity. Conversely, most electrocatalytic NO₂RR reaction investigations have found Pd and Pt to demonstrate ideal activity. Thus, there is a strong need to design multi-functional catalytic materials which aim to accelerate both NO₃RR and NO₂RR. Here, we aim to begin to the elucidate the impact of catalyst structure has on NO3RR and NO2RR for valorization (Nitrate to Ammonia). To accomplish this we develop Pd shape-controlled nanoparticles (e.g. nanocubes, cuboctahedrons, octahedrons, and concave nanocubes).