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

Abstract

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 (VO) decorated N-doped carbon nanorods on graphite paper (CeO2−x@NC/GP) were demonstrated as a highly efficient NO3−RR electrocatalyst. The CeO2−x@NC/GP catalyst manifests a significant NH3 yield up to 712.75 µmol·h−1cm−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 CeO2−x@NC/GP as cathode accomplishes a high-power density of 3.44 mWcm−2 and a large NH3 yield of 145.08 µmol·h−1cm−2. Density functional theory results further expose the NO3− reduction mechanism on CeO2 (111) surface with VO.