Tuning Interactions of Surface‐adsorbed Species over Fe−Co/K−Al<sub>2</sub>O<sub>3</sub> Catalyst by Different K Contents: Selective CO<sub>2</sub> Hydrogenation to Light Olefins
Thanapha Numpilai, Narong Chanlek, Yingyot Poo‐arporn, Chin Kui Cheng, Nuchanart Siri‐Nguan, Thana Sornchamni, Metta Chareonpanich, Paisan Kongkachuichay, Nevzat Yigit, Günther Rupprechter, Jumras Limtrakul, Thongthai Witoon
Abstract
Abstract Selective CO 2 hydrogenation to light olefins over Fe−Co/K−Al 2 O 3 catalysts was enhanced by tuning bonding strengths of adsorbed species by varying the content of the K promotor. Increasing the K/Fe atomic ratio from 0 to 0.5 increased the olefins/paraffins (O/P) ratio by 25.4 times, but then slightly raised upon ascending K/Fe to 2.5. The positive effect of K addition is attributed to the strong interaction of H adsorbed with the catalyst surface caused by the electron donor from K to Fe species. Although the Fe−Co/K−Al 2 O 3 catalyst with K/Fe=2.5 reached the highest O/P ratio of 7.6, the maximum yield of light olefins of 16.4 % was achieved by the catalyst promoted with K/Fe of 0.5. This is explained by the considerable reduction of amount of H 2 adsorbed on the catalyst surface with K/Fe=2.5.