Metal-metal interactions in catalysis from spatial separation to physical mixtures.

Physical mixtures of segregated metals recently demonstrated enhanced activity in redox reactions by assigning specific elementary steps to distinct sites to close the catalytic cycle through efficient transfer of reaction intermediates across conductive or reductive supports. Here, we delineate the fundamental shift from single static alloy sites to dual static separated structures, and ultimately to a dual dynamic mode. We term this mechanism dynamic interfacial cooperative catalysis. While collisions between identical single-sites provide no catalytic enhancement, collisions between distinct metal phases actively drive the reaction by facilitating cross-site electron and intermediate transfers. This dynamic synergy offers a blueprint for non-alloyed designs in high-concentration environments and energy-storage systems, including redox flow batteries.