Alloying of Cu with Ru Enabling the Relay Catalysis for Reduction of Nitrate to Ammonia.

Involving eight electron transfer process and multiple intermediates of nitrate reduction reaction (NO 3 RR) leads to a sluggish kinetic and low Faradic efficiency, therefore, it's essential to get an insight into the reaction mechanism to develop highly efficient electrocatalyst. Herein, a series of reduced graphene oxide supported RuCu alloy catalysts (Ru x Cu y /rGO) were fabricated and used for the direct reduction of NO 3 - to NH 3 . It is found that the Ru 1 Cu 10 /rGO shows the ammonia formation rate of 0.38 mmol cm -2 h -1 (loading 1 mg/cm 2 ) and the ammonia Faradic efficiency (FE) of 98% under an ultralow potential of -0.05 V versus RHE, which is comparable to Ru catalyst. The highly efficient activity of Ru 1 Cu 10 /rGO can be attributed to the synergetic effect between Ru and Cu sites via a relay catalysis, in which the Cu shows the exclusively efficient activity for the reduction of NO 3 - to NO 2 - and Ru exhibits the superior activity for NO 2 - to NH 3 . In addition, the doping of Ru into Cu tunes the d-band center of alloy and effectively modulates the adsorption energy of the NO 3 - and NO 2 - , which promotes the direct reduction of NO 3 - to NH 3 . This synergetic electrocatalysis strategy opens a new avenue for developing highly efficient multifunctional catalysts. This article is protected by copyright. All rights reserved.