Effect of Ce introduced Rh-UiO-66-Zr catalyst in syngas converting to ethanol

In the process of direct synthesis of ethanol from syngas, rhodium-based catalysts continue becoming a hot topic because of their high selectivity for C2 oxygen-containing compounds such as ethanol. In this work, UiO-66 was used as a support to introduce the metal Ce^{4 +} species into the Zr₆O₄(OH)₄ metal node of UiO-66-Zr to replace some of the metal Zr^{4 +} species formation Zr_6−xCe_xO₄(OH)₄ metal nodes, so as to accurately study the problem of ethanol activity sites for the preparation of syngas. The characterization results of XRD, TG, Raman, BET, H₂-TPR, XPS, and in-situ DRIFTS showed that with the introduction of metal Ce^{4 +} species at the UiO-66 Zr₆O₄(OH)₄ node, -(Zr-O)-Rh-(O-Ce)-sites were formed on the catalyst, and -(Zr-O)-Rh-(O-Zr)-sites were formed on the Rh/UiO-66-Zr catalyst. Combined with the evaluation results of the catalytic reaction, the number of ethanol active sites was significantly increased. Because of the interaction between Rh species and -(O-Zr)-species is stronger than Rh species with -(O-Ce)- sites, the potential difference of this interaction favors the efficient transport of electrons. On the other hand, -(Zr-O)-Rh-(O-Ce)- can stabilize the key intermediates for the preparation of ethanol from syngas, which can promote the formation of ethanol.