Increasing electrocatalytic nitrate reduction activity by controlling adsorption through PtRu alloying.

[Display omitted] • Pt 78 Ru 22 /C is six times more active than Pt/C at 0.1 V vs. RHE. • Pt x Ru y have 93–98% faradaic efficiencies towards NH 3 production at 0.1 V vs. RHE. • DFT calculations predict maximum activity at 25 at% Ru, consistent with experiments. • Maximum activity is due to a change in the rate determining step. Nitrate produced from industrial and agricultural processes has imbalanced the global nitrogen cycle. Electrocatalytic reduction is a sustainable route to remediate nitrate while generating products such as ammonia or N 2. Here we report the surface-area normalized activity of platinum-ruthenium (Pt x Ru y /C) catalysts of different compositions (x = 48–100%) for electrocatalytic nitrate reduction, chosen based on screening using a computational activity volcano plot. The Pt x Ru y /C alloys are more active than Pt/C, with Pt 78 Ru 22 /C six times more active than Pt/C at 0.1 V vs. RHE, and ammonia faradaic efficiencies of 93–98%. Density functional theory calculations predict maximum activity at 25 at% Ru, consistent with experiments. This maximum is due to a transition from nitrate dissociation as the rate determining step to a new rate-determining step at higher Ru content. This study demonstrates how electrocatalyst performance is tunable by changing the adsorption strength of reacting species through alloying. [ABSTRACT FROM AUTHOR]