Heteronuclear Rh-La Dual-Atom Sites Enable Pathway-Controlled Hydrogen Production in Ethanol Steam Reforming.

Achieving kinetic matching among elementary steps is critical for optimizing catalytic performance in complex reactions, yet rationally designing active sites to regulate distinct step kinetics remains a challenge. In ethanol steam reforming (ESR), an important route for sustainable hydrogen production, intrinsic ineffective kinetic coupling of C-C cleavage and water activation often leads to side reactions and deactivation. Here, we designed heteronuclear Rh-La dual-atom sites with complementary functions, where Rh governs C-C bond activation and carbon-intermediate transformation, while La promotes water activation. These sites are constructed via electronic metal-support interactions (EMSIs), where isolated La atoms anchored on Al2O3 electronically stabilize adjacent Rh atoms to form well-defined Rh-La pairs. This electronic cooperation enhances water activation and redirects the water-gas shift reaction from a redox route to a lower-barrier carboxylate-mediated route. Consequently, downstream CO conversion is accelerated to match upstream CO generation from C-C cleavage, enabling kinetic synchronization of key sequential steps. This leads to pathway-controlled hydrogen production with the highest reported H2 production rate (80.5 L g-1 h-1) to date and exceptional long-term stability. Furthermore, this strategy can be extended to other metal combinations, including Pd-La, Pt-La, and Ir-La, suggesting a general approach for designing cooperative catalytic sites for complex multistep reactions.