Interfacial engineering of in situ grown porous aromatic framework integrated electrodes for electrochemical nitric oxide reduction.

The electrocatalytic reduction of nitric oxide (NORR) offers an attractive route for simultaneously mitigating NO pollution and producing value-added ammonia under ambient conditions. However, conventional powder electrodes typically rely on polymer binders, which introduce additional interfacial resistance and limit efficient catalyst utilization.Herein, a binder-free integrated porous aromatic framework electrode (PAF-TPP-Co@CP) is fabricated through a three-step in situ growth strategy, directly integrating a cobalt-coordinated porous aromatic framework with a conductive carbon paper substrate. The resulting integrated architecture establishes intimate catalyst-substrate contact and interconnected porous transport pathways, facilitating interfacial charge transfer and molecular transport during NORR. Benefiting from this interface design, the PAF-TPP-Co@CP electrode achieves an ammonia yield rate of 956 ± 25 μg h-1 cm-2 and a Faradaic efficiency of 92.3 ± 1.8% at -0.6 V vs. RHE, corresponding to a 5.2-fold enhancement in ammonia yield compared with the powder electrode. Combined NO temperature-programmed desorption, in situ Raman spectroscopy, and density functional theory calculations reveal that CoN coordination sites promote NO adsorption and activation, while the integrated porous interface optimizes the electrochemical reaction microenvironment. This work demonstrates an effective strategy for constructing binder-free integrated porous electrodes and provides new insights into the role of interfacial architecture in electrocatalytic nitric oxide reduction.