CeO₂ nanoparticles with oxygen vacancies decorated N-doped carbon nanorods: A highly efficient catalyst for nitrate electroreduction to ammonia

Electrocatalytic nitrate reduction reaction (NO₃⁻RR) emerges as a highly efficient approach toward ammonia synthesis and degrading NO₃⁻ contaminant. In our study, CeO₂ nanoparticles with oxygen vacancies (V_O) decorated N-doped carbon nanorods on graphite paper (CeO_2−x@NC/GP) were demonstrated as a highly efficient NO₃⁻RR electrocatalyst. The CeO_2−x@NC/GP catalyst manifests a significant NH₃ yield up to 712.75 μmol·h⁻¹·cm⁻² at −0.8 V vs. reversible hydrogen electrode (RHE) and remarkable Faradaic efficiency of 92.93% at −0.5 V vs. RHE under alkaline conditions, with excellent durability. Additionally, an assembled Zn-NO₃⁻ battery with CeO_2−x@NC/GP as cathode accomplishes a high-power density of 3.44 mW·cm⁻² and a large NH₃ yield of 145.08 μmol·h⁻¹·cm⁻². Density functional theory results further expose the NO₃⁻ reduction mechanism on CeO₂ (111) surface with V_O.