Ammonia (NH 3 ) is essential for agriculture and plays an important role in next-generation carbon-free energy systems. Renewable NH 3 synthesis is a supplementary or alternative to the traditional Haber-Bosch process. The electrochemical nitrate reduction reaction (NO 3 − RR) to NH 3 offers a promising route for sustainable NH 3 production and effective nitrogen recovery. However, slow reaction kinetics and the competing hydrogen evolution reaction (HER) hinder the efficiency.
In a study published in Nature Synthesis , a team led by Prof. BAO Xinhe from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences developed a copper-palladium (CuPd) bimetallic catalyst, which dynamically formed abundant Cu-PdH x interfacial sites with high intrinsic catalytic activity in situ under NO 3 − RR conditions.
Under NO 3 − RR operating conditions, the CuPd bimetallic catalyst exhibited high intrinsic catalytic activity, achieving an NH 3 production rate of 19.9 mmol h −1 cm −2 with a current density of 5 A cm –2 at a full-cell voltage of 2.56 V in a membrane electrode assembly (MEA) electrolyzer. It demonstrated good durability, maintaining a Faradaic efficiency of about 86.8% at 2 A cm −2 for over 1,000 hours.
Researchers revealed that the enhanced performance was attributed to the superior intrinsic activity of the Cu-PdH x interfaces. The hydrogen redistribution induced by the overflow at the Cu-PdH x interface modified the local electronic structure of the active sites, which optimized the NO 3 − adsorption, promoted the NH 3 desorption, and provided a more energetically favorable reaction pathway for NH 3 synthesis.
A scale-up demonstration using an electrolyzer stack with five 100 cm 2 MEAs achieved an NH 3 production rate of 8.7 mol h –1 at 500 A, and continuously produced 1.6 mol h –1 of NH 3 at 100 A for 100 hours, underscoring the industrial applicability.
This study provides new insight into the structure-activity relationship of CuPd bimetallic sites. And it provides an effective strategy for enhancing intrinsic catalytic activity through the in situ construction of beneficial interfaces, enabling efficient conversion of nitrate pollutants into value-added NH 3 .
Nature Synthesis
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Copper–palladium hydride interfaces promote electrochemical ammonia synthesis
19-Nov-2025