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Intermittent pulsed electrocatalysis adjusting Cu valence states for effective nitrite reduction to ammonia
Nano Research 2025, 18(11): 94907810
Published: 22 September 2025
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Electrochemical nitrite (NO2) reduction offers a sustainable route for ammonia (NH3) synthesis while simultaneously removing contaminants in wastewater. However, its efficiency is often limited by low catalytic efficiency and the competitive hydrogen evolution reaction at low NO2 concentrations. Herein, we report an intermittent pulsed electrolysis (IPE) strategy using copper oxide (CuxO) nanowires, which significantly enhances the NH3 yield rate and Faradaic efficiency (FE) at lower reactant concentrations. In situ experiments and theoretical calculations reveal that alternating between open-circuit and cathodic potentials modulates the copper oxidation states, stabilizing the catalytically active cuprous oxide (Cu2O). Consequently, the IPE approach provides an outstanding NH3 yield rate of 115.10 mg·h−1·cm−2 and FE of 91.14% in the presence of 25 mM NO2, markedly outperforming conventional constant potential electrolysis.

Open Access Research Article Issue
Optimizing Electrocatalytic Hydrogen Evolution Stability via Minimal Bubble Adhesion at Electrodeposited Crack-Structured NiPx Catalysts
Energy & Environmental Materials 2024, 7(5): e12726
Published: 04 January 2024
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In response to the ongoing energy crisis, advancing the field of electrocatalytic water splitting is of utmost significance, necessitating the urgent development of high-performance, cost-effective, and durable hydrogen evolution reaction catalysts. But the generated gas bubble adherence to the electrode surface and sluggish separation contribute to significant energy loss, primarily due to the insufficient exposure of active sites, thus substantially hindering electrochemical performance. Here, we successfully developed a superaerophobic catalytic electrode by loading phosphorus-doped nickel metal (NiPx) onto various conductive substrates via an electrodeposition method. The electrode exhibits a unique surface structure, characterized by prominent surface fissures, which not only exposes additional active sites but also endows the electrode with superaerophobic properties. The NiPx/Ti electrode demonstrates superior electrocatalytic activity for hydrogen evolution reaction, significantly outperforming a platinum plate, displaying an overpotential of mere 216 mV to achieve a current density of −500 mA cm−2 in 1 M KOH. Furthermore, the NiPx/Ti electrode manifests outstanding durability and robustness during continuous electrolysis, maintaining stability at a current density of −10 mA cm−2 over a duration of 2000 h. Owing to the straightforward and scalable preparation methods, this highly efficient and stable NiPx/Ti electrocatalyst offers a novel strategy for the development of industrial water electrolysis.

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