Au Nanowires Decorated Ultrathin Co 3 O 4 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 (NO 3 RR) is an effective and green strategy for both nitrate treatment and ammonia production. As an electrochemical reaction, the NO 3 RR requires an efficient electrocatalyst for achieving high activity and selectivity. Inspired by the enhancement effect of heterostructure on electrocatalysis, Au nanowires decorated ultrathin Co 3 O 4 nanosheets (Co 3 O 4 -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 NO 3 RR. As the result, the Co 3 O 4 -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 Co 3 O 4 -NS/Au-NWs nanohybrids show an obviously plasmon-promoted activity for NO 3 RR due to the localized surface plasmon resonance (LSPR) property of Au-NWs, which can achieve an enhanced NH 3 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 NO 3 RR, which provide an efficient nitrate-to-ammonia reduction with high efficiency.