Cu/CuxO/Graphdiyne Tandem Catalyst for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Abstract

AbstractThe electrocatalytic reduction reaction of nitrate (NO3−) to ammonia (NH3) is a feasible way to achieve artificial nitrogen cycle. However, the low yield rate and poor selectivity toward NH3 product is a technical challenge. Here a graphdiyne (GDY)‐based tandem catalyst featuring Cu/CuxO nanoparticles anchored to GDY support (termed Cu/CuxO/GDY) for efficient electrocatalytic NO3− reduction is presented. A high NH3 yield rate of 25.4 mg h−1 mgcat.−1 (25.4 mg h−1 cm−2) with a Faradaic efficiency of 99.8% at an applied potential of −0.8 V versus RHE using the designed catalyst is achieved. These performance metrics outperform most reported NO3− to NH3 catalysts in the alkaline media. Electrochemical measurements and density functional theory reveal that the NO3− preferentially attacks Cu/CuxO, and the GDY can effectively catalyze the reduction of NO2− to NH3. This work highlights the efficacy of GDY as a new class of tandem catalysts for the artificial nitrogen cycle and provides powerful guidelines for the design of tandem electrocatalysts.