Synthesis-to-Catalysis Full-Process Cu Assistance in Cu/Fe5C2@C Catalysts for Photothermocatalytic Fischer–Tropsch Synthesis to Light Olefins

Fischer–Tropsch synthesis (FTS) offers a route for converting syngas from nonpetroleum resources into valuable chemicals, such as light olefins. χ-iron carbide (χ-Fe5C2), the key active phase for olefin production, is plagued by poor stability under practical conditions. Here, we propose a synthesis-to-catalysis full-process Cu-assisted strategy that integrates synthesis, photothermal conversion and reaction regulation into a design framework, thereby enabling a Cu/Fe5C2@C catalyst with improved durability and catalytic performance. The optimized 0.20Cu/Fe5C2@C catalyst achieves 48.7% light olefins selectivity, a 3.1-fold increase in light olefin yield compared to Fe5C2@C, and markedly improved long-term stability under photothermocatalytic FTS. Mechanistic studies reveal that the full-process synergy of Cu enhances catalytic performance by promoting the formation of a highly graphitized carbon shell to stabilize χ-Fe5C2 during synthesis, enhancing photothermal conversion efficiency via localized surface plasmon resonance, and optimizing reactant activation and the CH2* intermediate transformation toward light olefins. This work establishes a full-process regulation paradigm that integrates multistage functions, offering a transformative approach toward high-performance, durable solar-driven FTS for nonpetroleum resource utilization.