Paradigm Shift in Mechanistic Understanding and Catalyst Design for Heterogeneous Ethylene Methoxycarbonylation

Mechanistic principles from homogeneous catalysis are often applied to heterogeneous systems, but differences in coordination and electronic environments can lead to divergent reactivity. Uncritically transferring homogeneous paradigms─based on electron-state-tunable organometallic complexes─to electron-deficient, supported metal centers may cause counterproductive designs. Here, we report a reversed strategy: an oxide-supported, electron-deficient Ru center is used for ethylene methoxycarbonylation, replacing conventional organometallic complexes. A built-in moderately basic site facilitates a distinct proton transfer pathway, eliminating the need for strong external Brønsted acids. The RuO_x/TiO₂ catalyst shows over 80 times higher activity than Ru nanocatalysts and 6 times that of Pt single-atom catalysts. It also demonstrates exceptional stability over 180 h, with a turnover number exceeding 200,000, surpassing all known heterogeneous ethylene methoxycarbonylation catalysts and rivaling Pd catalysts.