Electrifying aldehydes into high-value chemicals presents a sustainable solution for environmental remediation, resource recovery and upgrade, yet its practical implementation has been limited by inefficient electrodes. Here, we develop a computation-guided strategy—localized hydrogen-affinity engineering—to synthesize heteroatom-decorated Cu hydrogenase for aldehydes electrification. Remarkably, the as-prepared Rh-decorated Cu hydrogenase (Rh1Cu-Hase) achieves a remarkable Faraday efficiency of >99.3% for formaldehyde conversion at an ultrahigh current density of 500 mA cm−2 with a minimal overpotential of 283 mV. A membrane-free electrolyzer equipped with the Rh1Cu-Hase operates stably for over 1200 h at 1000 mA cm−2, continuously producing high-purity potassium diformate (KDF) and hydrogen. Techno-economic analysis reveals a significant $166.1/ton KDF revenue advantage over conventional methods. The paired dehydrogenation mechanism is proposed by a series of operando studies and theoretical calculations, unveiling that the Cu matrix facilitates aldehyde adsorption, while atomic Rh sites activate hydrogen, collectively reducing energy barriers for both C─H cleavage and H─H coupling. Furthermore, the universality of this strategy is demonstrated by its successful application in electrifying a broad range of industrially relevant aldehydes.

Angew. Chem. Int. Ed. 2026, 65, e15456 https://doi.org/10.1002/anie.202515456