Aluminum ion (Al3+) remodels heterophase CuFe alloy to overcome the activity-stability trade-off in electrocatalytic nitrite electroreduction into ammonia

CuFeAl solid-solution alloy catalysts were constructed via Al 3+ -mediated electrodeposition. • The homogeneous alloy optimizes *NO 2 conversion, while Fe/Al-containing sites promote H 2 O activation and *H supply. • An in-situ generated oxygen-rich amorphous layer suppresses metal leaching and enhances long-term alkaline stability. • The catalyst achieves high NH 3 yield rates (>1.8 mmol h −1  cm −2 ) and FE (> 95%) with 800 h stability in MEA. The electrocatalytic nitrite reduction reaction (eNO 2 RR) to ammonia represents a sustainable alternative to the Haber-Bosch process, yet CuFe alloy catalysts for eNO 2 RR are constrained by insufficient active hydrogen (*H) supply and inevitable leaching of active centers in alkaline electrolytes, particularly under high current densities. Herein, we introduce non-electroactive aluminum ions (Al 3+ ) during electrodeposition to regulate the interfacial deposition environment and enable the formation of a homogeneous CuFeAl solid-solution alloy (CuFeAl−SSAC) from a phase-segregated CuFe system. Experimental and theoretical analyses reveal that the homogeneous Cu − Fe atomic arrangement regulates the adsorption and conversion of *NO 2 intermediates and lowers the energetic requirement of the initial hydrogenation step, while the Al-regulated interfacial environment promotes H 2 O activation and enhances reactive *H generation and utilization. During prolonged electrolysis, an oxygen-rich amorphous reconstructed surface layer forms, with Al-mediated O 2− /OH − interactions contributing to suppressing active sites dissolution. Consequently, CuFeAl−SSAC achieves an NH 3 yield rate of 7.1 mmol h −1  cm −2 with a faradaic efficiency (FE) of 96.2% in H-cell and sustains NH 3 yield rate of 1.8 mmol h −1  cm −2 with 95.0% FE for 800 h in membrane electrode assembly (MEA). This work highlights a strategy of aluminum incorporation for simultaneously enhancing catalytic activity and stability of electrocatalysts. Heterophase CuFe alloy (CuFe−TPAC) was remodeled into a homogeneous CuFeAl solid-solution catalyst (CuFeAl−SSAC) by introducing Al 3+ , which accelerates hydrogenation kinetics and forms a protective oxygen-rich amorphous layer to overcome the activity-stability trade-off in eNO 2 RR. This design achieves an exceptional NH 3 yield rate of 7.1 mmol h −1  cm −2 with 96.2% FE and over 800-h stability in membrane electrode assembly (MEA). Download: Download high-res image (152KB) Download: Download full-size image