ZrZnO x is active in catalyzing carbon dioxide (CO 2 ) hydrogenation to methanol (MeOH) via a synergy between ZnO x and ZrO x . Here we report the construction of Zn 2+ −O−Zr 4+ sites in a metal−organic framework (MOF) to reveal insights into the structural requirement for MeOH production. The Zn 2+ −O−Zr 4+ sites are obtained by postsynthetic treatment of Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 nodes of MOF-808 by ZnEt 2 and a mild thermal treatment to remove capping ligands and afford exposed metal sites for catalysis. The resultant MOF-808-Zn catalyst exhibits >99% MeOH selectivity in CO 2 hydrogenation at 250 °C and a high space-time yield of up to 190.7 mg MeOH g Zn −1 h −1 . The catalytic activity is stable for at least 100 h. X-ray absorption spectroscopy (XAS) analyses indicate the presence of Zn 2+ −O−Zr 4+ centers instead of Zn m O n clusters. Temperature-programmed desorption (TPD) of hydrogen and H/D exchange tests show the activation of H 2 by Zn 2+ centers. Open Zr 4+ sites are also critical, as Zn 2+ centers supported on Zr-based nodes of other MOFs without open Zr 4+ sites fail to produce MeOH. TPD of CO 2 reveals the importance of bicarbonate decomposition under reaction conditions in generating open Zr 4+ sites for CO 2 activation. The welldefined local structures of metal-oxo nodes in MOFs provide a unique opportunity to elucidate structural details of bifunctional catalytic centers.
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