Recently, the research team led by Prof. Chade Lv at the School of Chemistry and Chemical Engineering has achieved significant progress in the electrochemical nitrate reduction to ammonia. The team proposed and experimentally validated a novel strategy based on ohmic contact interface engineering, through which stable Cu0-Cuδ⁺ active sites were constructed. These active sites enable the efficient electroreduction of nitrate to ammonia at ampere-level current densities.. The related work, entitled “Stabilizing Cu0-Cuδ⁺ sites via ohmic contact interface engineering for ampere-level nitrate electroreduction to ammonia”, was published in Nature Communications. This achievement provides new insights into the future design of metal-semiconductor catalytic systems with tunable polarization, as well as their applications in multi-electron reduction reactions.
Schematic illustration of the design principle and construction of ohmic-contact interface engineering
The long-standing challenge of self-reduction-induced instability of active sites in copper-based catalysts during electrochemical nitrate reduction has been a significant issue.To tackle this problem, the team put forward an interface - regulation strategy based on work - function - difference - driven directional electron transfer. In the constructed Cu@indium hydroxide heterostructure, electrons spontaneously migrate from metallic copper to semiconducting indium hydroxide, resulting in the formation of stably polarized Cu⁰-Cuδ⁺ active sites. This polarization effectively suppresses the self-reduction of Cuδ⁺ species and maintains the long-term stability of the catalytic centers. This rational design not only enables efficient charge transport and enhanced reaction kinetics, but also provides a new structural stabilization pathway for metal–semiconductor interfacial electrocatalytic systems. Experimental results demonstrate that the Cu@indium hydroxide catalyst achieves a Faradaic efficiency of 97.35% and an ammonia yield rate of 4.28 mmol h-1 mg cat-1 at -0.6 V versus the reversible hydrogen electrode (RHE). Moreover, it exhibits stable operation for over 120 hours at an ampere-level current density of 800 mA cm-2, significantly outperforming conventional copper-based catalysts.
To gain a deeper understanding, in situ spectroscopic measurements and theoretical calculations elucidate the reaction mechanism of the Cu0-Cuδ⁺ active sites: highly polarized Cu0-Cuδ⁺ centers facilitate *NO2 adsorption and hydrogenation, whereas less polarized Cu0-Cuδ⁺ sites provide active hydrogen species, together enabling efficient conversion in key reaction steps.
The catalytic system also demonstrates excellent industrial application potential in a two-electrode flow electrolyzer. When coupled with the oxygen evolution reaction, the device delivers a current density of 1 A cm-2 at an applied voltage of only 2.0 V, while maintaining structural and performance stability during prolonged operation. This achievement marks a critical step forward for copper-based electrocatalysts toward high-current-density and industrial-scale ammonia synthesis.
Harbin Institute of Technology is the first corresponding affiliation of the paper. Researcher Chunshuang Yan, Prof. Xin Zhou, Prof. Chade Lv from the School of Chemistry and Chemical Engineering, Harbin Institute of Technology, and Prof. Guihua Yu from The University of Texas at Austin are the co-corresponding authors. Zeyu Li, a PhD candidate, is the first author, while Ming Zheng, Chu Zhang, and others participated in the research.
This work was supported by the National Natural Science Foundation of China, the Key Research and Development Program of Heilongjiang Province, the Natural Science Foundation of Heilongjiang Province, and related funding programs.
Paper link:https://doi.org/10.1038/s41467-025-63996-w
