Electrochemical conversion of NO3- to NH3 production is of great
environmental significance for water pollution treatment and can
artificially close the nitrogen cycle. However, direct nine proton and
eight electron transfer leads to low Faraday efficiency (FE) and yield.
Herein, the single copper site immobilized on N, P co-doped carbon
substrates (Cu-N4/P) was prepared for efficient NO3–to-NH3 conversion.
Benefiting from electronic redistribution of Cu site induced by the
introduction of the less electronegative element P, Cu-N4/P catalyst has
superior catalytic properties to the comparison sample, including 100%
NO3- conversion, high FE (96.12%) and NH3 yield (124.22 mmol/(h·gcat)).
Density functional theory (DFT) explains the effective operation
mechanism that P doping can promote the spontaneous hydrogenation of *NO
to form *NOH, thus promoting the formation of NH3 from NO3- reduction
reaction. The heteroatom doping strategy mentioned proposes a new
approach for promoting NO3–to-NH3 conversion at atomic level catalytic
sites.