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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Selective oxidation of methane to methanol by dioxygen (O 2 ) is an appealing route for upgrading abundant methane resource and represents one of the most challenging reactions in chemistry due to the overwhelmingly higher reactivity of the product (methanol) versus the reactant (methane). Here, we report that gold nanoparticles dispersed on mordenite efficiently catalyze the selective oxidation of methane to methanol by molecular oxygen in aqueous medium in the presence of carbon monoxide. The methanol productivity reaches 1300 μmol g cat −1 h −1 or 280 mmol g Au −1 h −1 with 75% selectivity at 150 °C, outperforming most catalysts reported under comparable conditions. Both hydroxyl radicals and hydroperoxide species participate in the activation and conversion of methane, while it is shown that the lower affinity of methanol on gold mainly accounts for higher methanol selectivity.