Nanoporous ternary intermetallic alloy for high-efficiency electrocatalytic nitroarene hydrogenation

Aromatic anilines are indispensable building blocks in the chemical industry, serving as key intermediates for agrochemicals, dyes, pharmaceuticals, etc. Electrocatalytic hydrogenation of nitrobenzene offers a mild, sustainable, highly controllable route for aniline synthesis. However, the high current density and remarkable faradaic efficiency of aniline are not simultaneously achieved. Herein, we develop a self-supported alloy electrode featuring an intermetallic Al₃Cu₂(Pd) phase anchored on a nanoporous Cu skeleton (np-8CuPd). Benefiting from its unique bimodal nanoporous architecture and ternary intermetallic composition, the np-8CuPd electrode delivers a remarkable nitrobenzene conversion of ∼93.6%, aniline selectivity of ∼99%, and an outstanding faradaic efficiency (FE_aniline) of ∼92.7%. These excellent metrics are achieved at an ultralow applied potential of -0.03 V (versus RHE) in a 1 M KOH aqueous solution containing 8 mM nitrobenzene, where a high current density of 154.6 mA cm^-2 is attained. Its exceptional electrocatalytic performance is attributed not only to its nanoporous architecture, which provides a high specific surface area and enables rapid mass/electron transport, but also, and more critically, to the bifunctional active sites within the ternary intermetallic phase. In this unique configuration, Pd sites facilitate H₂O dissociation to generate H* species, while the adjacent electron-deficient Cu sites ensure moderate adsorption of the substrate and reaction intermediates, thus significantly enhancing the selectivity toward aniline. This work establishes a promising strategy for the rational design of advanced electrocatalysts through controlled alloy composition and morphology engineering.