Highly Efficient Assembly-Line Production of Long-Chain Hydrocarbons via Fischer–Tropsch Synthesis over Ru/TiO2 Catalysts

The assembly-line strategy serves as an effective way for optimizing tandem steps in the fields of enzyme catalysis and homogeneous catalysis. Herein, we rationally construct efficient Ru/TiO2 catalysts for an important industrial heterogeneous reaction of Fischer-Tropsch synthesis (FTS), involving CO dissociation, hydrogenation, and C-C coupling complex processes. These catalysts feature an "assembly-line" structure composed of oxygen vacancies (Ov), interfacial Ru (RuIδ+ at RuIδ+-Ov-Ti3+), and exposed Ru (RuE0) sites. Both experimental and theoretical results demonstrate that RuIδ+ sites with the assistance of Ov primarily contribute to CO dissociation and hydrogenation to C1 monomers (workshop 1), while RuE0 sites predominantly drive the above intermediates to C-C coupling for carbon chain growth (workshop 2). We interestingly discover that besides the performance of the two workshops themselves, their efficient coordination is key to improve the activity and long-chain hydrocarbon selectivity in FTS. Optimizing this trisite catalytic system via tuning the prereduction time of the TiO2 support robustly achieves an ultrahigh FTS activity (180.8 molCO molRu-1 h-1) while maintaining an impressive C5+ selectivity (90.1%), outperforming the vast majority of state-of-the-art Ru-based FTS catalysts. This work not only clearly clarifies the synergistic mechanisms of multiple active sites but also offers valuable guidance for the application of the assembly-line strategy in complex heterogeneous catalysis reactions.