Selective conversion of syngas to light olefins

Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C-2(=)-C-4(=)) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theoretical limit of only 58% for C-2-C-4 hydrocarbons. We present a process that reaches C-2(=)-C-4(=) selectivity as high as 80% and C-2-C-4 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H-2, and C-C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is observed within 110 hours. Furthermore, this composite catalyst and the process may allow use of coal-and biomass-derived syngas with a low H-2/CO ratio.