Scalable and sustainable manufacturing of intermetallic nanocrystals for economical water splitting

Intermetallic nanocatalysts are pivotal for advancing energy conversion and storage technologies. However, their industrial-scale synthesis is fundamentally hindered by the difficulty of maintaining precise compositional and structural control. Here, we introduce a universal phase-engineering strategy, actualized through a continuous roll-flow radiative heating platform that enables the one-step, scalable, and controllable synthesis of highly ordered intermetallic nanocatalysts. This innovative technique demonstrates remarkable versatility, rendering precise fabrication of intermetallic nanocrystals across a vast compositional landscape. Crucially, by modulating key kinetic parameters during synthesis, we achieve precise control over ordering arrangement with fine-tuning of catalytic performance. As a proof of concept, we demonstrate the scalable and sustainable synthesis of nickel-iron intermetallic (Ni₃Fe) nanocatalysts with a predominant L1₂-ordered crystal structure for efficient alkaline water splitting. The resulting catalyst exhibits exceptional electrocatalytic activity, reaching a current density of 10 mA cm^-2 at a low overpotential of 200.2 mV, a performance that rivals the commercial iridium dioxide (IrO₂) benchmark (199.2 mV). Moreover, it shows outstanding long-term durability, with 99.9% current retention over 140 hours and negligible metal leaching. A comprehensive techno-economic evaluation reveals that the hydrogen production cost is strongly dependent on current density, projecting a highly competitive H₂ price as low as $2.33 kg^-1 at 1.0 A cm^-2. This work is expected to provide advanced technology for scalable, sustainable, and continuous manufacturing of intermetallic nanocrystals for economical water splitting.