Improved olefin selectivity on surface modified Fe/g-C3N4 in CO hydrogenation

Fe/graphitic carbon nitride (g-C3N4) catalysts exhibit good activity and olefin selectivity in CO hydrogenation, however, the strong interaction between Fe and carrier leads to difficulties in Fe reduction and activation, and further modification is needed to enhance their catalytic performance. In this study, unmodified Fe/g-C3N4, and surface-modified Fe/CNO, Fe/RCN, Fe/RCNO, and Fe/CN-HNO3 samples were prepared. The influence of surface modification on the textural properties of Fe/g-C3N4 and the product distribution of CO hydrogenation were investigated using series of characterization methods. The results show that the surface modification exhibits significant influence on the texture characteristics and catalytic properties of the catalysts. After modification, N defects exist on the surface of Fe/RCN, Fe/RCNO, and Fe/CN-HNO3. H2 pretreatment on Fe/RCN provides more active sites, promotes active phase formation, and improves CO adsorption and activation. In CO hydrogenation, the formation of CH4 is inhibited, and the olefin selectivity is greatly improved on Fe/RCN. The proposed method provides a new approach to optimizing the catalytic performance for better FTS.