Programming Cascade Catalysis in Multielement Dual-Heterostructured Catalysts Through Gradient Adsorption Potentials

Catalytic reactions involving multiple intermediates are fundamentally constrained by the limited functionality of single active sites. While multi-site catalysts provide a promising route to decouple complex reaction steps, the rational design and realization of architectures that enable rapid and directional inter-site intermediate spillover remains largely unexplored and highly challenging. Here, we report a strategy to program intermediate spillover and cascade catalysis in multielement dual-heterostructured catalysts through gradient adsorption potentials. Using the acidic oxygen evolution reaction as a model, a dual-heterostructured RuIr-Mo/WVOx catalyst is precisely engineered to integrate an oxyphilic WVOx matrix for rapid water dissociation, a Mo bridge for efficient ^*OHspillover, and a RuIr alloy for accelerated oxidation. Guided by first-principles screening and differences in elemental reducibility, a continuous gradient adsorption sequence (WVOx → Mo → RuIr) is constructed from a multielement architecture, enabling directional ^*OH transport across cooperatively coupled active centers with balanced energetics for cascade catalysis. As a result, the optimized catalyst delivers an overpotential of 183 mV at 10 mA cm^{- 2} and sustains stable operation for 450 h at 100 mA cm^{- 2}, outperforming single-interface and commercial benchmarks. This work establishes gradient adsorption engineering as a general design framework for programming cascade catalysis in multistep reactions.