A vacancy engineered MnO2-x electrocatalyst promotes nitrate electroreduction to ammonia

The NO3- reduction reaction (NO3RR) has recently emerged as a potential approach for sustainable and efficient NH3 production, whereas exploring high-performance NO3RR electrocatalysts is highly desirable yet challenging. Herein, we attempted to construct O-vacancies (OVs) on MnO2 nanosheets and the resulting OV-rich MnO2-x showed a high NH3 yield of 3.34 mg h(-1) cm(-2) (at -1.0 V vs. RHE) and an excellent FE of 92.4% (at -0.9 V vs. RHE), together with the outstanding stability. DFT calculations reveal that OVs on MnO2 serve as catalytic centers to enhance NO3- adsorption and dissociation, reduce the energy barriers of hydrogenation steps and thus promote NO3--to-NH3 conversion.

Automated summary

This study attempted to construct O-vacancies on MnO2 nanosheets, resulting in OV-rich MnO2-x catalysts that exhibited high NH3 yield, excellent FE, and outstanding stability in the NO3RR reaction.