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

Abstract The electrocatalytic reduction reaction of nitrate (NO 3 − ) to ammonia (NH 3 ) is a feasible way to achieve artificial nitrogen cycle. However, the low yield rate and poor selectivity toward NH 3 product is a technical challenge. Here a graphdiyne (GDY)‐based tandem catalyst featuring Cu/Cu x O nanoparticles anchored to GDY support (termed Cu/Cu x O/GDY) for efficient electrocatalytic NO 3 − reduction is presented. A high NH 3 yield rate of 25.4 mg h −1 mg cat. −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 NO 3 − to NH 3 catalysts in the alkaline media. Electrochemical measurements and density functional theory reveal that the NO 3 − preferentially attacks Cu/Cu x O, and the GDY can effectively catalyze the reduction of NO 2 − to NH 3 . 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.