Au Nanowires Decorated Ultrathin Co3O4 Nanosheets toward Light-Enhanced Nitrate Electroreduction

Nitrate is a reasonable alternative instead of nitrogen for ammonia production due to the low bond energy, large water-solubility, and high chemical polarity for good absorption. Nitrate electroreduction reaction (NO3RR) is an effective and green strategy for both nitrate treatment and ammonia production. As an electrochemical reaction, the NO3RR requires an efficient electrocatalyst for achieving high activity and selectivity. Inspired by the enhancement effect of heterostructure on electrocatalysis, Au nanowires decorated ultrathin Co3O4 nanosheets (Co3O4-NS/Au-NWs) nanohybrids are proposed for improving the efficiency of nitrate-to-ammonia electroreduction. Theoretical calculation reveals that Au heteroatoms can effectively adjust the electron structure of Co active centers and reduce the energy barrier of the determining step (*NO -> *NOH) during NO3RR. As the result, the Co3O4-NS/Au-NWs nanohybrids achieve an outstanding catalytic performance with high yield rate (2.661 mg h(-1) mg(cat)(-1)) toward nitrate-to-ammonia. Importantly, the Co3O4-NS/Au-NWs nanohybrids show an obviously plasmon-promoted activity for NO3RR due to the localized surface plasmon resonance (LSPR) property of Au-NWs, which can achieve an enhanced NH3 yield rate of 4.045 mg h(-1) mg(cat)(-1). This study reveals the structure-activity relationship of heterostructure and LSPR-promotion effect toward NO3RR, which provide an efficient nitrate-to-ammonia reduction with high efficiency.

Automated summary

Nitrate is a viable alternative to nitrogen for ammonia production due to its properties of low bond energy, large water-solubility, and high chemical polarity. The electroreduction reaction of nitrate (NO3RR) is an effective and environmentally friendly strategy for nitrate treatment and ammonia production. In this study, Au nanowires decorated ultrathin Co3O4 nanosheets are proposed as an efficient electrocatalyst for nitrate-to-ammonia electroreduction. The nanohybrids achieve a high catalytic performance and an enhanced NH3 yield rate due to the effect of heterostructure and localized surface plasmon resonance (LSPR) property of Au-NWs.